appendix c - bloomcoll.com.au complex...figure 10 glennies creek alluvium cross sections and...

Groundwater Assessment

A P P E N D I X C

GeoTerra Pty Ltd ABN 82 117 674 941

77 Abergeldie Street Dulwich Hill NSW 2203

Phone: 02 9560 6583 Fax: 02 9560 6584 Mobile 0417 003 502 Email: [email protected]

GC13-R1E

12 June, 2009

GEOTERRA PTY LTD INTEGRA COAL OPERATIONS PTY LTD

INTEGRA OPEN CUT PROJECT AND

OPEN CUT EXTENSION GROUNDWATER ASSESSMENT

Singleton, NSW

GeoTerra

GC13-R1E (12 JUNE, 2009) GeoTerra

Integra Coal Operations Pty Ltd PO Box 3060 SINGLETON NSW 2330 Attention: Bob Corbett Bob, RE: BARRET HEBDEN AND MIDDLE LIDDELL SEAM MINING

GROUNDWATER ASSESSMENT Please find enclosed a copy of the above mentioned report.

Yours Faithfully

GeoTerra Pty Ltd

Andrew Dawkins Managing Geoscientist (MAusIMM CP-Enviro)

Distribution: Original Geoterra Pty Ltd

1 electronic copy Integra Coal Operations Pty Ltd

1 electronic copy URS Pty Ltd


Authorised on behalf of Geoterra Pty Ltd:

Name: Andrew Dawkins

Signature:

Position: Managing Geoscientist

Date Rev Comments Initial Draft 27.10.2008 A Incorporate review comments 18.11.2008 B Incorporate review comments 17.12.2008 C Incorporate review comments 04.06.2009 D Incorporate adequacy review comments 12.06.2009 E Remove text highlighting


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TABLE OF CONTENTS

EXECUTIVE SUMMARY VI

1. INTRODUCTION 1

1.1 Open Cut Project 2

1.2 Open Cut Extension 2

1.3 Study Objectives 3

1.4 Local Mining 4

1.4.1 Waste Management 6 1.4.2 Previous Groundwater Studies 7

2. STUDY AREA FEATURES 8

2.1 Geomorphology 8

2.2 Soils 8

2.3 Climate 8

2.4 Surface Hydrology 9

2.4.1 Glennies Creek 9 2.4.2 Station Creek 10

2.5 Geology 11

2.5.1 Seams to be Mined 11 2.6 Mine Area Hydrogeology 13

2.6.1 DWE Registered Bores and Wells 14 2.6.2 Alluvium 14 2.6.3 Foybrook Formation 15

2.7 Groundwater Chemistry 15

3. HYDROGEOLOGICAL INVESTIGATION PROGRAM 16

3.1 Groundwater Investigations 16

3.2 Hydraulic Properties 16

3.3 Standing Water levels 17

3.4 Water Chemistry 18

4. LABORATORY INVESTIGATIONS 22

4.1 Bore Water Chemistry 22


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5. DATA INTERPRETATION 23

5.1 Hydrogeology 23

5.1.1 Glennies Creek and Station Creek Alluvium 23 5.1.2 Foybrook Formation Interburden and Coal Seams 23

5.2 Groundwater Flow 26

5.3 Alluvial and Foybrook Formation Test Pumping and Recovery Water Levels 27

5.3.1 Glennies / Station Creek Alluvium 27 5.3.2 Foybrook Formation 27

5.4 Water Chemistry 27

5.4.1 Groundwater 27 5.4.2 Stream Water 28

5.5 Potential Pit Void Water Quality 28

5.6 Hydraulic Connection Between the Foybrook Formation and Quaternary Alluvium 29

5.7 Connected and Disconnected Alluvium Zones To Glennies Creek 30

6. GROUNDWATER MODELLING 34

6.1 Conceptual Hydrogeological Model 34

6.1.1 Integra Mining Schedule 35 6.1.2 Recharge 35

6.2 Modelling Code 36

6.2.1 Model Structure 36 6.3 Sensitivity Analysis 40

6.4 Model Calibration 40

6.5 Potential Impact on Local Groundwater Systems and Groundwater Users of the “Full Pit” 41

6.5.1 Foybrook Formation 41 6.5.2 Quaternary Aquifers 46

6.6 Potential “Full” Pit Inflows 53

6.7 Post Mining “Full” Pit Void Water Levels 53

7. POTENTIAL “FULL PIT” WATER QUALITY IMPACTS 54

7.1 Potential Salt / Contaminant Migration Pathways 54

7.2 Potential Impacts on Regional Groundwater Quality 54

7.3 Potential Impacts on Regional Surface Water Quality 54

7.4 Potential Final Void Water Quality 55


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8. POTENTIAL “FULL PIT” IMPACT ON STREAM FLOWS AND GROUNDWATER DEPENDENT ECOSYSTEMS 55

8.1 Local Creeks 55

8.2 Potential Impacts on Groundwater Dependent Ecosystems 55

9. POTENTIAL GROUNDWATER IMPACTS OF THE PART PIT 56

10. MONITORING, REHABILITATION, CONTINGENCY MEASURES AND REPORTING56

10.1 Monitoring 56

10.1.1 Standing Water Level 56 10.1.2 Groundwater Quality 57 10.1.3 Monitoring Procedures 58 10.1.4 Private Bore and Well Groundwater Levels, Yield and Groundwater Quality 58 10.1.5 Mine Water Pumping 58 10.1.6 Rainfall 58 10.1.7 Ongoing Monitoring 58 10.1.8 Quality Assurance and Control 59

10.2 Contingency Measures 59

10.3 Impact Assessment Criteria 59

10.3.1 Groundwater Levels and Yield 59 10.3.2 Groundwater Quality 60

10.4 Piezometer Licensing, Maintenance and Installation 61

10.5 Rehabilitation 61

10.6 Reporting 61

11. SUMMARY AND CONCLUSIONS 62

12. COVERAGE OF DIRECTOR-GENERAL’S REQUIREMENTS 65

13. REFERENCES 65


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FIGURES Figure 1 Study Area......................................................................................................... 5 Figure 2 Mine Area Upper and Lower Seams Depth of Cover ...................................... 12 Figure 3 South Pit Extension Groundwater Levels........................................................ 19 Figure 4 South Pit Extension Groundwater Pressures .................................................. 20 Figure 5 Foybrook Formation Groundwater Salinity and pH ......................................... 21 Figure 6 Glennies & Station Creek Groundwater Salinity and pH ................................. 22 Figure 7 Hydraulic Conductivity Vs Depth ..................................................................... 24 Figure 8 Open Cut Project Area Groundwater Chemistry ............................................. 28 Figure 9 Glennies Creek Alluvium Salinity, Hydraulic Conductivity and pH Vs Distance

From Glennies Creek ...................................................................................... 32 Figure 10 Glennies Creek Alluvium Cross Sections and Groundwater Profiles .......... 33 Figure 11 Anticipated Integra Mining Operations......................................................... 35 Figure 12 Model Extent................................................................................................ 37 Figure 13 Model Cross Sections.................................................................................. 39 Figure 14 Hebden Seam Drawdown, Year 2014 ......................................................... 42 Figure 15 Hebden Seam Drawdown, Year 2018 ......................................................... 43 Figure 16 Hebden Seam Drawdown, Year 2024 ......................................................... 44 Figure 17 Hebden Seam Drawdown, Year 2031 ......................................................... 45 Figure 18 Modelled Alluvium Drawdown Near The Proposed Pit ................................ 47 Figure 19 Modelled Flow Loss from Glennies Creek .............................................. 48 Figure 20 Modelled (Layer 1 ) Alluvium Drawdown, Year 2014................................... 49 Figure 21 Modelled (Layer 1 ) Alluvium Drawdown, Year 2018................................... 50 Figure 22 Modelled (Layer 1 ) Alluvium Drawdown, Year 2024................................... 51 Figure 23 Modelled (Layer 1 ) Alluvium Drawdown, Year 2031................................... 52

DRAWINGS

Drawing 1 Site Layout

Drawing 2 Stream Monitoring Sites DWE Registered Bores and Wells

Drawing 3 Foybrook Formation Piezometric Surface

Drawing 4 Glennies Creek Alluvium Piezometric Surface


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TABLES

Table 1 Local Mining Operations

Table 2 Glennies Creek Water Extraction

Table 3 Department of Water and Energy Registered Bore Data

Table 4 Piezometer Licence Details

Table 5 Laboratory Water Chemistry

Table 6 Glennies Creek Alluvium Features

Table 7 Parameters Used in the Proposed Pit Model

Table 8 Glennies Creek Alluvium Groundwater Gradient

Table 9 Potential Proposed Pit Groundwater Inflows (Without Evaporation)

Table 10 Standing Water Level Monitoring Method and Frequency

Table 11 Groundwater Quality Monitoring Parameters

Table 12 Groundwater Quality Monitoring Method and Frequency

Table 13 Groundwater Quality Impact Assessment Criteria

APPENDICES

Appendix A Piezometer Details

Appendix B Hydraulic Tests

Appendix C Groundwater Laboratory Analyses

Appendix D Groundwater Modelling


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EXECUTIVE SUMMARY

Integra Coal Operations Pty Ltd (Integra) propose to extend their existing South Pit in a north-westerly direction. The extension to the South Pit is planned to be excavated to an approximate maximum depth of 250m below surface over a period of up to approximately nine years. Mining operations will include the extraction of a sequence of coal seams between the Lemington Seam and the Upper Hebden Seam.

Geographical area subdivisions referred to in this report are outlined below;

• proposed Pit the proposed extension of the existing South Pit, which is subdivided into the Full Pit Extent or the Part Pit Extent (see below).

• Full Pit Extent 160ha Pit area which includes mining within the Dulwich property area

• Part Pit Extent 113ha area which excludes mining within the Dulwich property area

• Open Cut Project Area 1,876ha area shown in Drawing 1

• Open Cut Extension Area 801 ha area including the coal handling and preparation plant, the existing South Pit, open cut area (including the Mine Area) and 200ha of grazing and pasture land

• Open Cut Area 284ha area within which open cut activities will take place including additional activities such as topsoil and subsoil storage, the haul route along the western boundary of the Mine Area and surface water drainage management devices

• Mine Area area proposed to be mined, i.e. Full Pit Extent or Part Pit Extent

• Study Area The study area encompasses the area shown in Figure 1

• North Open Cut Project Area 376ha area which includes the North Open Cut as shown in Drawing 1 (formerly known as the Glennies Creek Open Cut)

• Existing South Pit existing operational South Pit

• Extended South Pit 407 ha area comprising the proposed Pit and the existing South Pit.

The coal sequence is currently being mined by open cut methods by Integra in the adjoining South Pit, and was previously mined in the now backfilled former North Pit. The backfilled North Pit is situated northeast of the proposed Mine Area, and is north of the South Pit.

Drilling, monitoring and field testing of 39 piezometers within the Integra mine leases indicate very low groundwater yields (<0.04L/sec) in the Foybrook Formation coal measures and low permeabilities (<0.2L/sec) in alluvium. Six open standpipe piezometers were installed up to


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14m below surface in the Station Creek / Glennies Creek alluvium; six were installed up to 56.3m below surface in the coal measures and two multi-intake vibrating wire piezometers were installed down to the Hebden Seam at a maximum depth of 197m.

Field, laboratory and office assessments indicate that:

• the Foybrook Formation groundwater pH ranges from 6.5 to 8.5, with salinity between 1185µS/cm and 14,490µS/cm;

• the Station Creek / Glennies Creek alluvium groundwater pH ranges from 6.9 to 8.9, with salinity between 743µS/cm and 20,300µS/cm; and

• water accumulating in the final void is likely to exhibit a pH of approximately pH 8.5 and a salinity of 11,350µS/cm.

The proposed Pit will be excavated through the Permian Foybrook Formation overburden and interburden which contains a sequence of coal measures between the Lemington Seam and the Hebden Seam.

There will be no excavation through Quaternary alluvium or alluvial aquifers associated with Station Creek or Glennies Creek, as the edge of the proposed Pit will be located at least 150m east of the Station Creek valley fill alluvium, and will be approximately 350m east of Glennies Creek. The Station Creek and Glennies Creek alluvium consists of interbedded clay, sandy clay and gravelly units that range up to 14m below surface.

The seams and their associated overburden / interburden lie within a 6O west-north-westerly dipping sequence which is located to the east of the northerly trending Camberwell Anticline. Based on limited data, it is interpreted that one north-easterly trending fault zone with up to 5m displacement may be present to the west of the proposed Pit, whilst a second fault zone may intersect the western most edge of the proposed Pit.

The Mine Area is located within an essentially dry, ephemeral first and second order stream catchment which drains to the ephemeral channel of Station Creek, which in turn, flows into the perennial Glennies Creek. Glennies Creek then drains into the Hunter River approximately 5km south-west of the junction with Glennies Creek. The Mine Area is located within a low rainfall, high evaporation climatic regime.

The major creeks within and adjacent to the Open Cut Project Area were generally flowing during the study period, with Station Creek exhibiting a pH range of 6.0 to 9.5 and an electrical conductivity of 100 to 1900µS/cm, while Glennies Creek exhibited a range of pH 6.2 to 9.7 and average salinities between 335 to 500µS/cm. The salinity in Glennies Creek has reached a maximum since 2002 of 950µS/cm.

All four of the Department of Water and Energy (DWE) registered wells within or near the Open Cut Project Area were installed in the alluvium of Glennies Creek, however only one is present and active (GW67291). Two registered bores are registered to be within or near the Open Cut Project Area, however only Richards Bore (GW80968) is active and is being used as a monitoring piezometer by the DWE.

Short duration pump out tests and falling head tests assessed the Quaternary alluvium to have hydraulic conductivities ranging from 0.015m/day to approximately 0.61m/day, whilst the conductivities of the coal seams and interburden ranged from 8.64x10-7 to 4.8m/day.

Groundwater within the various seams to be extracted are generally confined, except where they are depressurised through extraction of the existing South Pit or they extend underneath the Station Creek and Glennies Creek alluvium.


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Groundwater quality of the tested overburden, interburden and selected seams exceeds the ANZECC 2000 upland stream freshwater and 95% trigger level for freshwater species for pH, electrolytical conductivity, total nitrogen, total phosphorus, copper, and to a lesser degree, zinc and aluminium.

An assessment of acid rock drainage indicates that the waste rock is not potentially acid producing (WRM Water & Environment, 2008A).

A FEFLOW groundwater model was sequentially developed as the understanding of the regional hydrogeological system developed. The model represented the Open Cut Project Area with 11 layers which incorporated the proposed coal extraction in the proposed Pit as well as the effect of adjacent open cut and underground mine workings.

Modelling indicates a regionally limited area of groundwater depressurisation due directly to development of the proposed Pit, however the drawdown in the Mine Area is combined with depressurisation from adjacent open cut and underground mines in the local area on both sides of Glennies Creek.

Modelling predicts that up to the Year 2018, when the proposed Pit is due to be completed, the regional drawdown within the Hebden Seam will extend underneath Glennies Creek. However drawdown in the alluvium is not modelled to extend into the creek channel. Depressurisation of the Quaternary alluvium of Glennies Creek within the vicinity of the proposed Pit is predicted to occur. However, no observable change in stream flow is predicted within Glennies Creek as a result of development of the proposed Pit due to the minor change in alluvial groundwater outflow from the current 3.1ML/day to 4.2ML/day in 2018.

Current depressurisation around the existing South and Rix’s Creek Pits will substantially limit the rate of inflow to the proposed Pit and will partly mask the regional groundwater drawdown effects. Pit inflows of between the current 35ML/year to 117ML/year in 2018 are postulated by the modelling. However, the high evaporation rate would significantly reduce the volume of any water required to be pumped out of the Pit.

The model indicates that the nearest operating DWE registered bore (Richards Bore) may be affected by less than 1m of groundwater depressurisation due to mining the proposed Pit, however the bore could also currently be affected by mining within an adjacent operating mine. Similarly, the active well (GW67291) is modelled to be affected by less than 1m of drawdown.

No adverse effects on stream flow or stream water quality are anticipated for Station Creek, or its associated alluvial groundwater system.

Less than 2m of drawdown is anticipated within the connected alluvium of Glennies Creek due to the proposed open cut mining. The modelled drawdown is similar to the current variability in alluvial groundwater levels of up to 0.76m. As a result, the change in groundwater levels within the connected alluvium of Glennies Creek is not anticipated to adversely or observably affect stream flow or stream water quality in Glennies Creek.

Up to 7m of indirect drawdown is modelled in the disconnected, distant, very low permeability, clay dominated alluvial sediments in GCP26 which is approximately 760m to the south / east of Glennies Creek. The maximum drawdown will not occur until after 2024 when the Hebden Seam underground workings will be completed, and could occur up to 2031 when the Barrett Seam underground workings are proposed to be completed. The drawdown will not be due to the proposed open cut workings, as they are proposed to be completed in 2018.


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No adverse effect on alluvial or coal measures groundwater quality is anticipated in the Open Cut Project Area from development of the “Full” or “Part” Pit.

No adverse effects are anticipated on Groundwater Dependent Ecosystems in the Open Cut Project Area.

Water within the final void could range up to a salinity of approximately 11,350µS/cm, depending on the relative proportions of groundwater inflow, dirty water pumped into the void, surface water runoff and evaporation, with a pH of approximately 8.5 (WRM Water & Environment, 2008A).

Post-mining groundwater levels are modelled to partially recover following the cessation of mining, with the final relative level being dependent on the hydrogeological conditions prevalent at the time as well as the quantity of water pumped into the void from other storages across the Open Cut Project Area, as the final void is potentially to be used as an on-site dirty water storage and evaporation facility for the Integra Underground. However, the water management volumes are not detailed at this stage.


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1. INTRODUCTION Integra Coal Operations Pty Ltd (Integra) is the management company responsible for operations at the existing approved Integra Open Cut (formerly known as the Camberwell Coal Mine) and the Integra Underground (formerly known as the Glennies Creek Colliery) which are located approximately 10km north-west of Singleton in NSW.

Integra is proposing to extend the existing South Pit, which has operated continuously since 11 March 1991, in a north-westerly direction. The objective of the proposed development is to maximise resource utilisation within and above CL357, thereby extending the Integra Open Cut's economic life by up to approximately nine years.

Geographical area subdivisions referred to in this report are outlined below;

• proposed Pit the proposed extension of the existing South Pit, which is subdivided into the Full Pit Extent or the Part Pit Extent (see below). Also called the proposed Pit

• Full Pit Extent 160ha area which includes mining within the Dulwich property area

• Part Pit Extent 113ha area which excludes mining within the Dulwich property area

• Open Cut Project Area 1,876ha area shown in Drawing 1

• Open Cut Extension Area 801ha area including the coal handling and preparation plant, the existing South Pit, open cut area (including the Mine Area) and 200ha of grazing and pasture land

• Open Cut Area 284ha area within which open cut activities will take place including additional activities such as topsoil and subsoil storage, the haul route along the western boundary of the Mine Area and surface water drainage management devices

• Mine Area area proposed to be mined, i.e. Full Pit Extent or Part Pit Extent

• Study Area The study area encompasses the area shown in Figure 1

• North Open Cut Project Area 376ha area which includes the North Open Cut as shown in Drawing 1 (formerly known as the Glennies Creek Open Cut)

• Existing South Pit existing operational South Pit

• Extended South Pit 407 ha area comprising the proposed Pit and the existing South Pit.


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Should the annual production rate be less than the maximum sought and/or projected for any year, the duration of the proposed mining activities would be extended. Additionally, any coal mined through highwall mining methods may increase the mine life.

Notwithstanding, it is anticipated that the maximum operational life of the Full Pit Extent would be up to approximately 9 years for excavation of the Pit and up to 12 years, in total, should coal also be mined through highwall mining methods. Rehabilitation activities will extend the overall life of the Open Cut Extension by up to a total of approximately 14 years.

1.1 Open Cut Project In addition to the proposed Pit, and as part of the Integra Open Cut Project, this application also seeks approval for the long-term use of the Coal Handling and Preparation Plant (CHPP), train loader, infrastructure and facilities required for or to support mining and processing and despatch of coal from the Integra Open Cut Project, and to replace DA 86/2889 (the existing Integra Open Cut Development approval) and PA 06_0073 (the Glennies Creek Open Cut (approved) through the provision of a consolidated project approval.

The proposed development area (the "Open Cut Project Area") is shown in Figure 1 and encompasses:

• all areas of disturbance and activities associated with the extension to the existing South Pit (the "Open Cut Extension Area") including clearance of land; open cut mining and related activities such as overburden and soil placement; installation of water management structures and rehabilitation; coal haulage to and processing within the existing approved CHPP;

• the Glennies Creek Open Cut Project Site (now known as the North Open Cut) identified in PA 06_0073; and

• the Development Application Area identified in DA86/2889

Additionally, for administrative or practical purposes, the Open Cut Project Area also incorporates the access road corridor between the Development Application Area boundary and Bridgman Road and the area to the north of the PA 06_0073 Project Site boundary and south of Middle Falbrook and Stony Creek Roads.

The Open Cut Project Area, Open Cut Extension Area, Open Cut Area and the Mine Area are shown in Drawing 1.

1.2 Open Cut Extension The 801ha Open Cut Extension Area comprises four principle sub-component areas, namely the:

• 284ha Open Cut Area, including the proposed 160ha Mine Area or proposed Pit which is to be subject to coal extraction. The remaining 124ha within the Open Cut Area will remain essentially undisturbed, with the only activities being soil storage and installation of surface water management structures and a haul road adjacent to the pit highwall;


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• South Pit (247ha);

• coal haulage corridor (13ha); and

• CHPP Area (57ha). The CHPP Area includes the coal preparation plant, ROM and product coal stockpiles, the trainloader, the workshop, stores, water fill point, fuel farm, bath house, administration buildings and associated facilities.

The remaining 200ha within the Open Cut Extension Area will remain essentially undisturbed by project related activities.

The Open Cut Area, South Pit, coal haulage corridor, CHPP area and the majority of the 200ha to remain essentially undisturbed lie within CL357, with the South Pit, coal haulage corridor and CHPP area comprising areas of current mining activity.

The area to the east and south of the Open Cut Extension Area has also been substantially modified by current and past coal mining activities at the Integra Open Cut North Pit and the Rix's Creek Coal Mine.

The majority of the land within the Open Cut Extension Area is owned by RHA Pastoral Company Pty Ltd, a subsidiary of Camberwell Coal Pty Ltd, with the remainder owned by two private landowners, IM Tisdell and R & D Hall.

The Hall property, "Dulwich", and a component of the Tisdell property lie within the footprint of the planned Full Pit Extent. Integra is currently discussing the purchase of the two properties with the respective landowners, with Mrs Tisdell having indicated a willingness to sell subject to negotiation of a satisfactory price.

In the event that the Dulwich property is not acquired or a suitable alternative arrangement cannot be reached with the landowner which permits mining the Full Pit Extent, and subject to the receipt of planning approval, coal extraction will be undertaken to the limits permissible under the Mining Act 1992. The Part Pit Extent is approximately 113ha in size as shown in Drawing 1.

This document addresses the relevant issues pertaining to development of the Full Pit Extent. However, in the cumulative impact assessment, the report also assesses the impact of other mining operations in the local area, including the North Open Cut.

The Open Cut Area is located on a west facing slope that has been extensively cleared and is currently used for cattle grazing.

1.3 Study Objectives This document provides an assessment of the current baseline and post mining impacts on the local and regional hydrogeology from development of the proposed “Full” Pit.

The objective of the study was to provide Integra Coal Operations Pty Ltd (Integra) with an understanding of the local and regional groundwater system and to assess the potential combined effects from mining the proposed Pit in terms of:

• potential groundwater inflows to the Pit,

• the potential effect on local and regional coal measures groundwater systems; and

• the potential effect on adjacent alluvial groundwater and stream systems.


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The study describes potential groundwater management and mine water supply issues that may arise, as well as outlining the potential effects on the local environment and regional bores that may occur due to operation of the proposed Pit.

The study is based on the “Full” Pit extraction scenario shown in Drawing 1. The “Full” Pit includes mining through the “Dulwich” property and will involve coal extraction activities over an area of approximately 160ha.

Where appropriate, the study also assesses the impacts to the Dulwich property of mining the “Part” Pit , should the Dulwich property not be acquired.

The field, office and laboratory analyses enabled a conceptual hydrogeological model to be derived, with subsequent development of a “FEFLOW” computer based model which sequentially modelled the development of the proposed “Full” Pit and adjacent mine workings, and assessed the potential local and regional effects from operation and decommissioning of the proposed Pit. Modelling enabled:

• the simulation of hydrogeological systems in the vicinity of the proposed Pit;

• an assessment of potential water supply and Pit dewatering requirements; and;

• an assessment of the regional groundwater and potential environmental impacts.

1.4 Local Mining Associated and independent coal mining activities in the local area which currently are, or may in the future, have an interference effect with the hydrogeological system in the vicinity of the proposed Pit are shown in Figure 1, and include the:

• Integra South Pit immediately to the east (Pikes Gully to Upper Hebden Seams);

• Backfilled Integra North Pit to the northeast (Arties to Upper Hebden Seams);

• Approved Integra North Open Cut to the northeast (Middle Liddell to Upper Hebden Seams);

• Integra Underground to the north, and on the northern side of Glennies Creek (Middle Liddell Seam to Hebden Seam)

• Rix’s Creek Open Cut immediately to the south (Lemington to Barrett Seams);

• Felix Resources Ashton Open Cut to the north-west, on the northern side of Glennies Creek (Pikes Gully to Lower Barrett Seams);

• Felix Resources Ashton Underground to the north-west, on the northern side of Glennies Creek (Pikes Gully Seam); and

• Xstrata Glendell Open Cut Mine to the north-west, on the northern side of Glennies Creek (Upper Bayswater to Lower Barrett Seams).


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Figure 1 Study Area

Other mines which are nearby, although not likely to generate interference with the proposed Pit’s hydrogeological system as they are located to the north of the Integra Underground, are the:

• Xstrata Eastern Rail Pit (Ravensworth U and V Seams);

• Xstrata Ravensworth East ( Ravensworth to Bayswater Seams); and the

• Xstrata Mt Owen Open Cut (Lemington to Hebden Seams).

Projected ROM coal production from the proposed “Full” Pit will range from approximately 2.3 to 4.2 Mtpa, while waste movement is estimated to range from approximately 12 to 26 Mbcm per annum. However, approval is to be sought for ROM coal production up to a maximum of 4.5 Mtpa.

The floor of the proposed “Full” Pit will range from approximately 100m to 250m below ground level.

Soil stripping would be undertaken prior to mining to conserve the topsoil and subsoil for use in subsequent rehabilitation activities. Where possible, soil will be placed directly onto

South Pit

North Pit (backfilled)

Glennies Creek

Ashton Pit

Ashton Underground

Rixs Creek

Pit

Station Creek

Proposed “Full” Pit

Hunter River

Integra Underground

Glendell Open Cut

North Open Cut

Open Cut Project Area


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previously shaped areas within the South Pit or the Mine Area awaiting rehabilitation in lieu of stockpiling. Where direct placement of soil materials is not possible, they will be stockpiled in designated stockpile areas.

Mining within the proposed “Full” Pit would either commence in the middle of the western side of the existing South Pit and then progress in a northerly then southerly direction, or advance the northern highwall within the South Pit operation further to the north and subsequently advance southwards, with the ultimate decision regarding the commencement location and ongoing mining direction to be based on the ownership of the Dulwich property at the start of mining.

During the course of the planned open cut mining operations there may be opportunities to undertake mining from the final highwall or economic limit of the Upper Hebden Seam using auger or highwall mining methods (where such mining would not encroach within 150m of the Station Creek or Glennies Creek alluvials), with the final extent determined by the type of mining undertaken.

Neither highwall nor auger mining would generate any subsidence within the Open Cut Project Area. Any coal extracted by these methods would be in addition to the coal to be extracted by open cut mining.

1.4.1 Waste Management

The principle wastes to be generated and managed as part of the proposed mining activities would remain unchanged from those currently produced and would comprise overburden and interburden removed to access the coal seams as well as coarse and fine rejects produced within the CHPP.

The coarse and fine rejects comprise a mixture of coal and non-coal materials which occur naturally within the coal seam or represent overburden or interburden materials which are incorporated with the coal during mining.

Overburden strata within both the current South Pit and the proposed Pit are variable in nature, comprising conglomerate, sandstones, mudstones and claystones, and range from moderate to high strength.

Overburden / interburden and coarse reject from the CHPP will be dumped by truck into active tipping areas within the current South Pit area or in the mined-out components of the proposed Pit such that final landform within the Pit will blend with, and be consistent with, that approved within the South Pit and be to a maximum elevation of 150m AHD.

Fine reject (tailings) produced from coal processing will be managed in the same manner as that from the existing Integra Open Cut and the Integra Underground operations.

Given that the Integra Underground will remain in operation for some 15 years after the cessation of the proposed Pit, the potential exists for the use of part of the eastern portion of the South Pit void for tailings management and the south western portion of the proposed Pit for dirty water management in the longer term.

Rehabilitation including earthworks, drainage and revegetation is being undertaken progressively as part of the existing South Pit operations in a manner consistent with the design provided in the Camberwell EIS, the closure criteria developed for sustainable pasture and native ecosystems and the "Synoptic Plan: Integrated Landscapes for Coal Mine Rehabilitation in the Hunter Valley". These activities will be extended into the areas of disturbance within the Open Cut Area.


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The conceptual final landform will be consistent with that identified in the current South Pit Mining Operations Plan in terms of slope grade, drainage lines and the boundary landform with Rix's Creek Colliery.

The objectives of the rehabilitation will be to:

• reshape all slopes to gradients which provide long term stability;

• revegetate lands disturbed by mining activities;

• return the site to a suitable land capability class;

• locate dams on natural and reformed watercourses and gullies to provide short term retention and sediment control during mining and rehabilitation, and long term stock watering and/or fauna utilization / habitat;

• prevent contaminants from leaving the site; and

• minimise dust generation during the rehabilitation process.

1.4.2 Previous Groundwater Studies

Almost all of the open cut and underground coal mines in the vicinity of the Open Cut Project Area have publicly available groundwater baseline and groundwater modelling studies.

This study has used the available reference material to develop the regional hydrogeological understanding; to aid in developing input parameters for the proposed Pit groundwater computer model, and to assist with assessing the potential cumulative impacts of surrounding operations on the Open Cut Project Area.

Table 1 summarises the publicly available findings in terms of potential mine inflows and affects on local Quaternary alluvial aquifers.

It should be noted that although they are outside the Open Cut Project Area, the Xstrata Mt Owen, as well as the Xstrata Eastern Rail Pit and the Xstrata Glendell open cut operations will or have involved diversion and potential shortening of the Bettys Creek channel, which significantly reduces alluvium recharge and stream flow away from Bettys Creek.

Integra are also currently proposing to extract the Barrett Seam and the Hebden Seam as an extension of the current workings in the Integra Underground Middle Lliddell Seam mining area under a separate approval process to the Extended South Pit. The Barrett underground longwall workings are proposed to be located to the north of the North Open Cut and North Pit, whilst the Hebden longwall workings are proposed underneath the current Middle Liddell Seam workings. Cut and flit mining areas associated with the longwall workings are proposed to be located between the Barrett and Hebden longwall workings, and underneath the Glennies Creek Alluvium. This proposal is discussed in detail in (Geoterra, 2008) and is discussed, where relevant to the proposed Pit, in Section 6 of this report. Figure 13 in Section 6 of this report shows the location of the proposed underground workings.

It should be noted that the proposed Underground Project Area workings are designed so that they do not subside Glennies Creek or its associated alluvium and will not generate adverse changes to the alluvial groundwater system or stream flow within Glennies Creek.


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Table 1 Local Existing or Approved Mining Operations

MINE TYPE Operator

Max Depth (mbg)

Max Mine Inflow (L/sec) (ML/yr) Seams Mined

Seepage Affect on Alluvium (L/sec / ML/yr) Source

Rixs Ck OC Rixs Creek Collieries n/a n/a Pikes Gully to Hebden None n/a

South Pit OC Integra Coal 170 5.8 / 183 Arties to Upp Hebden None MER, 2000

North Pit OC (d) Integra Coal 120 9.3 / 292 Middle Liddell to

Hebden None MER, 2000

North Open Cut OC (p) Integra Coal 100 3.0 / 95 Pikes Gully to Lower Barrett negligible from Glennies Ck AGE, 2007

Barrett OC Ashton Coal 180 n/a Pikes Gully to Lower Barrett n/a n/a

Ashton Underground LW Ashton Coal 35 - 150 17 / 536 Pikes Gully 0.4-3.4L/s (14 -106ML/yr)

from Glennies Ck PJD, 2006

Glendell OC Xstrata 195 13.9 / 438 Upper Bayswater to

Barrett negligible from Bettys Ck Umwelt, 07

Ravensworth East OC Xstrata 45 n/a Ravensworth to

Bayswater combined total of MER, 2003

Eastern Rail Pit OC Xstrata 35 n/a Ravensworth 0.09L/s (2.9ML/yr) MER, 2003

Mt Owen OC Xstrata 270 6.9 / 219 Lemington to

Lower Hebden from Bettys Creek MER, 2003

Integra Underground LW Integra Coal 270 - 500 5.8 / 183 Middle Liddell negligible from Bettys Ck Geoterra,

2006

NOTES: OC Open cut LW longwall d decommissioned p proposed mbg m below ground

n/a not available

2. STUDY AREA FEATURES The Study Area encompasses the area shown in Figure 1.

2.1 Geomorphology As shown in Drawing 1, the proposed Open Cut Extension Area comprises:

• the existing South Pit which abuts the eastern boundary of the proposed Pit;

• the South Pit Haul road and the CHPP;

• north-west draining hillslopes that are mostly cleared;

• the stream channel and alluvial plains of Station Creek which have been cleared for cattle grazing, with only scattered trees and a eucalypt “tree lot” remaining; and

• the eastern alluvial plain of Glennies Creek which has been generally cleared for cattle grazing and the Glennies Creek stream channel.

2.2 Soils Hillslope derived colluvial soil within the proposed Mine Area range up to 1m to 2m deep, graduating into alluvial based sediments derived from Station Creek and Glennies Creek overbank deposits which can be up to 14m deep.

2.3 Climate The approximate mean annual rainfall ranges from 660mm to 735mm, with maximum monthly rainfalls occurring during the summer months.

Mean annual evaporation (based on a Class A evaporation pan) recorded at Jerry’s Plains Post Office (Station No. 61086), 22km west of the mine site, is approximately 1613mm, which is substantially higher than the mean annual rainfall.


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Mean evaporation is similar to mean rainfall in the winter months, but substantially exceeds rainfall for the remainder of the year.

2.4 Surface Hydrology

2.4.1 Glennies Creek

The Open Cut Project Area as well as the Open Cut Area both lie wholly within the Glennies Creek Catchment.

Glennies Creek (also known as Fal Brook) is a tributary to the Hunter River and joins the Hunter River near Maison Dieu to the west of Singleton. Glennies Creek is a Schedule 3 Stream as defined by DIPNR (2005).

The Glennies Creek - Status of the Natural Resources Report (Hunter Catchment Management Trust, 2003) states that the Glennies Creek catchment has an area of approximately 51,200ha.

Glennies Creek is dammed to the north of the Open Cut Project Area, with Lake St Clair formed behind the dam. The dam was constructed in 1963. Water releases from Lake St Clair, together with releases from the Glenbawn Dam on the Hunter River, are regulated to ensure that flows within the Hunter River meet the requirements of the Water Sharing Plan for the Hunter Regulated River Water Source.

Water flows within Glennies Creek were measured at The Rocks Gauging Station, which is approximately 12.3km to the northeast of the Open Cut Project Area, from 1944 to 1963 and exhibited a mean daily flow of 166ML, with a maximum recorded daily flow volume of 33, 273ML.

Glennies Creek has a perennial, although variable flow depending on rainfall / runoff and dam releases, with the catchment area between Glennies Creek Dam and the Middle Falbrook gauging station (No. 210044), which is located at the Middle Falbrook Road bridge (Integra monitoring Site GC1- Drawing 2), being approximately 240 km2.

The effect of Glennies Creek Dam is to moderate peak flows and increase base flows. At the start of each water year, 20,000ML is planned to be reserved for environmental contingency use in the Glenbawn and Glennies Creek storages.

Glennies Creek, above its junction with the Hunter River, constitutes Zone 3 of the Water Sharing Plan for the Hunter Regulated River Water Source, with the Plan aiming to limit long term extractions to approximately 20% of long term average flow.

At present there are 13 licensed water extraction points from Glennies Creek between Nobles Crossing (Integra monitoring Site GC2) and the confluence with Station Creek (Integra monitoring Site GC5), with up to 1018ML/year entitled to be extracted from the creek each year as shown in Table 2.

The location of the Integra stream monitoring sites are shown in Drawing 2.


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Table 2 Glennies Creek Water Extraction

Entitlement Users Volume (ML/yr)

Supplementary water 2 30.2

Stock and Domestic 1 8

General Security 8 727

High Security 2 253

TOTAL 13 1018.20

2.4.2 Station Creek

The Open Cut Area and the proposed Mine Area are located entirely within the south-westerly draining ephemeral catchment of Station Creek, which drains to Glennies Creek, which in turn flows into the Hunter River.

The Mine Area has been located a minimum of 150m from the eastern edge of the identified Station Creek alluvium.

An ephemeral tributary of Station Creek, colloquially known as Tisdell’s Creek, drains into Station Creek in the central western edge of the Open Cut Area near the Station Creek confluence with Glennies Creek, but lies outside, and to the south of, the proposed Mine Area as shown in Drawing 1.

The proposed Mine Area contains 3 small to medium sized earthen wall dams within the Tisdell’s Creek channel as well as 12 small earthen wall dams on the hillslopes above the Station Creek channel.

The Open Cut Area, external to the Mine Area, contains a further 7 small to medium sized earthen wall dams that are located on the hillslopes away from the Station Creek channel.

Flow characteristics of watercourses traversing the Open Cut Project Area are variable and dependent on precipitation duration and intensity, as well as soil moisture and the effect of evapo-transpiration.

No coal measure or alluvial groundwater baseflow was observed to discharge into Station Creek or Tisdell’s Creek due to their elevated positions within an upland, moderately sloping catchment. Alluvial groundwater baseflow to Glennies Creek is envisaged to occur along the creek line, although none has been directly observed to date.

Coal measures groundwater baseflow to Glennies Creek is also possible after extended high rainfall periods, however seepage from the Foybrook Formation was not directly observed during the study period since August 2007.

Runoff and streamflow are closely related to rainfall events in the ephemeral Station Creek and Tisdell’s Creek, with flows prone to rapid peaking and depletion and a tendency to no or low flow over extended periods.

Significant, longer term flooding would be restricted mainly to Glennies Creek, which is approximately 600m west of the closest point to the proposed Pit edge.


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2.5 Geology The Open Cut Area is covered by shallow hillslope-based colluvial Quaternary clay and sand in the eastern section associated with the westerly draining slopes of Station Creek, along with alluvium in the lower elevation, central and western sections which is sourced from Glennies Creek and Station Creek overbank sedimentary deposition.

The colluvium and alluvium is, in turn, underlain by coal measures associated with the Permian Foybrook Formation which contains interlayered sandstone, conglomerate, mudstone, siltstone and numerous coal seams.

The Quaternary unconfined and variably saturated alluvium associated with Station Creek and Glennies Creek can be up to 14m deep and comprises loams overlying silty and clayey sands with occasional cleaner sand and basal gravels overlying weathered coal measures.

The main structural features in proximity to the Open Cut Area are two north-east trending faulted zones which are indicatively mapped along the eastern edge of Glennies Creek and underneath the Station Creek alluvium as shown in Figure 2 and Drawing 3. Both faulted zones may have up to approximately 5m of throw and are mapped to extend to the north of the Mine Area under the channel of Glennies Creek. The exact location and inclination of the eastern faulted zone is not accurately known in relation to the proposed Pit, as its position has been based on drill hole data extrapolation. However it may potentially intersect the western-most portion of the proposed Pit.

The “hinge” or shallowest section of the northerly trending Camberwell Anticline is present on the western margin of the proposed Pit, whilst the Rixs Creek syncline is located on the south-western edge of the proposed Mine Area.

The Lemington Seam and underlying seams strike in an essentially northerly direction and dip primarily to the north-west at approximately 6O within the Mine Area.

2.5.1 Seams to be Mined

Coal extraction within the South Pit currently occurs from the 360 ply (Lemington Seam) to the 60 ply (Lower Hebden Seam).

Extraction within the proposed Mine Area would target coal from the 360 to the 105 plies (Lower Barrett Seam) and, subject to further economic evaluation, may also involve total or partial extraction of the 90 to 10 plies (Upper and Lower Hebden seam). Seams and plies planned to be mined within the proposed Pit from shallowest to deepest are as follows:

• Lemington Seam (Ply 360)

• Pikes Gully Seam (Plies 280 to 350)

• Arties Seam (Plies 229 to 271)

• Upper Middle Liddell Seam (Plies 200 to 220)

• Middle Liddell Seam (Plies 170 to 192)

• Lower Liddell Seam (Plies 130 to 163)

• Barrett Seam (Plies 100 to 121)

• Upper and Lower Hebden Seams (Plies 60 to 90)


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Figure 2 Mine Area Upper and Lower Seams Depth of Cover

The high overburden to coal stripping ratios within the Mine Area mean maximum recovery of raw coal is essential to the economic viability of the operation. Coal plies down to a minimum mining thickness of 30cm will be recovered completely and plies in the 10cm to 30cm thickness range will be evaluated individually to determine the economic viability of recovery.

The current South Pit operation has recovered plies to a thickness of 10cm where conditions are favourable.

As the mine is characterised by several 10-40m intervals of overburden/interburden across the deposit, waste materials will be mined by blasting and/or ripping then loading by shovel, excavator or front end loader into haul trucks.

360 Ply

(Shallowest)

70 Ply

(Deepest

Proposed

Mine Area Proposed

Mine Area

South Pit

South Pit

Strata Dip

Strata Dip

? ?

Camberwell

Anticline

Approx Fault

Location

? ?

Approx Fault

Location

Camberwell

Anticline


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2.6 Mine Area Hydrogeology Two types of aquifer systems are present in the vicinity of the proposed Mine Area, namely:

• unconsolidated alluvium in Station and Glennies Creeks; and

• shallow and deep basement coal measures comprising a variable sequence of aquicludes (mudstones and shales), aquitards (sandstones) and low yielding aquifers (coal seams) within the Foybrook Formation.

Neither the coal measures nor creek alluvium are listed as vulnerable aquifers under the current Aquifer Risk Assessment Report (DLWC, 1998). However, they are covered, as appropriate, by the generic State Groundwater Policy (DLWC, 1997), Groundwater Quality Protection Policy (DLWC, 1998) and Groundwater Dependent Ecosystem Policy (DLWC, 2002).

Development of the proposed Pit will involve excavation into the outcropping Permian Foybrook Formation, with the Pit edge located at least 150m to the east of the adjoining Station Creek and Glennies Creek Quaternary alluvium. The proposed Pit and its associated alluvium are located within the (Draft) Hunter Unregulated and Alluvial Water Sources Water Sharing Plan area (DWE, 2008).

The objectives of the Water Sharing Plan will be to:

• protect the important water dependent environmental, aboriginal, cultural and heritage values;

• protect basic landholder rights;

• manage the river and alluvial groundwater to ensure equitable sharing between users;

• provide opportunities for market based trading of licences and water allocations;

• provide flexibility for licence users in how they can use their water; and

• allow for adaptive management, that is, to allow changes to be made when more information is available.

The outcropping Foybrook Formation and the Quaternary alluvium are recharge sources to the regional groundwater system. Rainfall recharge into the basement is considered, however, to be relatively low to negligible based on measured hydraulic conductivities of different strata and observed water level movements in monitoring bores throughout the Integra Open Cut and the Integra Underground Project Areas.

No substantial aquifers are known to be present within the proposed Pit area other than groundwater of very limited yield and moderate salinity within the sequentially layered coal seams.


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2.6.1 DWE Registered Bores and Wells

No groundwater extraction is conducted within the study area from either alluvial or basement formations.

There are three registered wells and one registered DWE monitoring bore within the potential drawdown area of the proposed Pit as shown in Table 3 and Drawing 2. Bores GW45084 and GW67291 are located in proximity to the Open Cut Project Area, but lie outside the potential drawdown area around the proposed Pit.

Based on limited available data, the historical wells yielded up to 1.0 L/sec and ranged up to 27.4m deep whilst the monitoring bore is 30m deep. The three wells installed between 1938 and 1962 are no longer in operation, whilst GW67291 is still in use.

Richards Bore (GW80968) is a DWE monitoring bore located in close proximity to the Felix Resources Ltd Ashton Underground mine and is potentially experiencing depressurisation from that operation’s extraction of the Pikes Gully Seam. The standing water level, pH and salinity in Richards Bore is regularly monitored by the Integra Open Cut environmental staff.

No registered bores obtain a water supply from Quaternary Alluvium within the Open Cut Project Area.

Table 3 Department of Water and Energy Registered Bores in the Local Area

Type E N SWL

mAHD TD

mbg Intake SWL mbg

SWL mbtoc

Yield (L/sec) S/Up

GLENNIES CREEK ALLUVIUM GW13603 well 323257 6405314 n/a 12.8 n/a n/a n/a n/a n/a GW19565 well 323349 6406055 n/a 7.3 n/a n/a n/a n/a n/a GW52859 well 323160 6404942 n/a 9.1 n/a n/a n/a n/a n/a GW67291 well 326263 6408140 n/a 27.4 n/a n/a n/a n/a n/a

BASEMENT GW45084 bore 322029 6406833 n/a 18.9 n/a n/a n/a n/a n/a

Richards Bore (GW80968) bore 321110 6405184 47.87 30 18-24 15.13 15.53 1.0 0.40

NOTE: n/a data not available mbg metres below ground SWL standing water level

L/sec litres per second S/up stick up mbtoc metres below top of casing

Shading indicates bore in current use

2.6.2 Alluvium

The Glennies Creek alluvial aquifer is defined as a “shallow upriver” aquifer (DWE, 2008), and is characterised by low permeability clay based sediments overlying basal clayey gravels. It is considered to be “connected” to Glennies Creek, although the rainfall recharge / groundwater seepage to the creek is significantly delayed due to the low permeability of the shallow alluvium overlying the basal gravelly clay.

Glennies Creek is a “Gaining Stream”, with the creek channel being below the elevation of the influent alluvial groundwater table. The alluvial groundwater system recharges the stream flow via seepage into the creek, except during short lived high stream flow events where the reverse temporarily occurs.


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Station Creek is generally a “Losing Stream” as the stream channel is elevated above the underlying alluvial groundwater piezometric surface. The Station Creek alluvial aquifer is also less connected to Station Creek, compared to the Glennies Creek alluvial system, as it is characterised by more clay based, lower permeability alluvium overlying thinner, smaller grainsize basal gravels.

Based on data from coal exploration activities, piezometer drilling and the DWE, the proposed Pit has been located at least 150m east of the edge of the Quaternary alluvium associated with Glennies Creek and Station Creek, which is in accordance with the current Department of Water and Energy guidelines (DIPNR, 2005). The depth of alluvium increases toward Glennies Creek and current data indicates it can be up to 14m thick. The depth of alluvium may be deeper or more variable in places where drilling has not been conducted, however the overall characteristics of the aquifer are considered to be adequately assessed to date.

The generally shallow, clay dominated alluvium with underlying basal gravels does not provide any groundwater supply due to its low yield, high salinity, limited depth, limited extent and seasonally fluctuating water levels. No monitoring of alluvial groundwater levels in the local Glennies Creek alluvial system has been conducted to date by the DWE or its predecessors. Natural recharge of the coal measures from the Glennies Creek alluvium has been monitored at approximately 2L/sec (62ML/year) to the Pikes Gully Seam in the Ashton Underground Longwall 1 area. Following extraction of Longwall 4, it was estimated that total inflows to the Ashton Underground would be around 2.3L/sec (73ML/yr) (Aquaterra, 2008).

2.6.3 Foybrook Formation

The underlying Foybrook Formation is essentially a porous rock aquifer where groundwater occurs within the pore space of the rock matrix. In some localities it may also be a localised, secondary fractured rock aquifer where faulting or, alternatively, jointing associated with bedding flexure in the Camberwell Anticline, may have increased the hydraulic conductivity of the formation.

No water supplies are obtained from the Foybrook Formation in DWE registered bores within the Open Cut Project Area. Available data indicates that the Foybrook Formation contains low yielding (<1.0L/sec) aquifers with standing water levels between 7.0m and 44.3m below surface.

The shallowest seams to be mined (Lemington Seam and Pikes Gully Seam) subcrop within Glennies Creek near the Middle Fallbrook Road bridge as well as near the junction of Glennies Creek and Station Creek. The subcropping seams are potentially recharged by direct connection to the stream. However, due to the high degree of Quaternary sedimentation in the stream, no coal seams outcropping in the creek bed have been directly observed. The deeper seams down to the Middle Liddell Seam subcrop progressively further upstream of the Middle Fallbrook Road bridge in Glennies Creek as well as progressively further downstream of the Glennies Creek / Station Creek junction. The Middle Liddell Seam and the stratigraphically underlying seams do not outcrop in Glennies Creek within the Integra Open Cut and Integra Underground Project Areas.

2.7 Groundwater Chemistry No DWE data is available for registered bores or wells in the study area.


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3. HYDROGEOLOGICAL INVESTIGATION PROGRAM 3.1 Groundwater Investigations Drilling, piezometer installation, low flow pump out tests, falling head tests, packer tests and installation of open standpipe and vibrating wire piezometers, as well as groundwater level and water chemistry monitoring were conducted within the Study Area between September 2007 and August 2008 to provide input data to development of a “FEFLOW” model and assessment of the hydrogeological characteristics of the:

• Glennies Creek and Station Creek Alluvium;

• Foybrook Formation overburden and interburden; and

• interlayered coal seams.

To date, the groundwater investigation program across the Integra Open Cut and Underground leases has involved the installation of 41 piezometers up to 523m below surface as shown in Drawings 3 and 4.

Test monitoring bore licences supplied by the DWE are shown in Table 4, whilst geological logs and piezometer construction details relevant to this study are shown in Appendix A.

It should be noted that as vibrating wire piezometer arrays were installed in bores GCP35, GCP37, DDH223 and DDH224, and as these bores were sealed to surface with cement / bentonite on completion of the installation, no DWE licences are required.

Table 4 Piezometer Licence Details

Piezometer Bore Licence No.

GCP 25, 26 20BL171705

GCP 27 20BL171881

GCP 28, 29, 36 20BL171722

GCP 30, 31 20BL171720

GCP 32, 33 20BL171880

GCP 34 20BL171879

GCP 38 20BL171878

3.2 Hydraulic Properties For the current study, short duration, low flow (< 0.2L/sec) pump out tests of less than 20 minutes duration, along with rising or falling head tests were conducted within selected open standpipe piezometers within the Integra Open Cut and Integra Underground Project Areas, with the results of tests conducted on various coal seams and interburden layers shown in Table 5 and Appendix B.

Results from previous studies (AGE Pty Ltd, 2007) were also used in this assessment.


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Table 5 Hydraulic Parameters and Standing Water levels

Bore Property Total Depth

(m)

Alluvium

Depth (m)

Intake / Screen

(m)

Hydraulic Conductivity

(m/day)

Transmissivity

(m2/day)

Standing Water

Level (mbgl)

ALLUVIUM

GCP 25 RHA Pastoral 13 13 6.0 - 13 0.04H n/a 7.67

GCP 26 RHA Pastoral 11 11 7.0 – 11.0 0.015 – 0.017J 0.077 – 0.083J 5.36

GCP 28 RHA Pastoral 12 12 6.7 – 12.0 0.17H n/a 6.53


GCP 30 RHA Pastoral 12 12 5.5 – 12.0 0.06J 0.03J 5.04


FOYBROOK FM

GCP 27 RHA Pastoral 37.5 6 (approx) 35.5 – 37.5 0.32H n/a 7.59

GCP 32 Tisdells 55.6 12.0 49.0 – 55.0 0.03 – 0.036J 0.179 – 0.22 7.01

GCP 33 Tisdells 5 absent (dry) (dry) (dry) Dry

GCP 34 Tisdells 56.3 absent 47.1 – 56.3 0.37H n/a 44.25

GCP 35VWP RHA Pastoral 197 absent 72 / 147 / 195 8.64x10-3 – 8.64x10-7 n/a See Figure 3


GCP 37VWP RHA Pastoral 127.5 absent 70 / 125 8.64x10-3 – 8.64x10-6 n/a See Figure 3

GCP 38 RHA Pastoral 24.3 absent 17.0 -24.3 0.018J 0.131 – 0.129 6.74

Note: H hydraulic conductivity determined by falling / rising head Hvorslev method J hydraulic conductivity / transmissivity determined by pump out test / Jacob method

VWP for full vibrating wire piezometer data see Appendix B

In addition, packer tests over 5.5m intervals were conducted within GCP35, GCP37 and DDH224 prior to installing vibrating wire piezometers in those boreholes (SCT, 2008 / SCT 2008A).

Measured coal seam hydraulic conductivities vary from 1.037x10-2m/day to 3.456x10-4m/day whilst the interburden hydraulic conductivity varies from 4.8m/day to 8.64x10-7m/day.

3.3 Standing Water levels Standing water levels in available piezometers have been measured within the Open Cut Project Area since November 2006 as shown in Figure 3. Additional monitoring within the Integra Open Cut and Underground lease areas has been conducted since April 2005.

Longer term monitoring in Richards Bore, within the Foybrook Formation near the Ashton Underground Workings to the west of the Open Cut Project Area, indicates a relatively stable standing water level with no distinctive response to the increased rainfall since around June 2007.


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Monitoring in open standpipe piezometers within the Foybrook Formation since July 2007 indicates relatively stable to slightly falling groundwater levels, with short term, sharp, dips in water level representing pump out tests conducted on the piezometers.

Monitoring at various intake depths with cement / bentonite sealed vibrating wire piezometers (VWPs) installed in GCP35 and GCP37 indicated the shallower VWPs generally required one to two weeks to settle down following their installation. The VWPs currently show the phreatic standing water levels range from 35m to 38m below surface, whilst at the latest logger download, he deeper intake piezometer (GCP35_195mbgl) was still equilibrating with adjoining formations in the vicinity of the proposed Pit as the standing water level has not yet stabilised as shown in Figure 3.

The Glennies Creek / Station Creek alluvium monitoring in the Open Cut Project Area that has been undertaken since September 2007 indicates relatively stable standing water levels once the piezometers equilibrated with their adjoining formations after drilling. The alluvium standing water levels generally range between 4m and 8m below surface.

3.4 Water Chemistry Groundwater salinity and pH within the Foybrook Formation and Glennies Creek / Station Creek alluvium has been monitored within the Open Cut Project Area since July 2007.

All groundwater samples are collected, stored and despatched in accordance with AS/NZS 5667 (Standards Australia, 1998). The field water quality parameters are measured in the field using Hanna probes and meters which are freshly calibrated with two point pH buffers and EC standards bracketing the expected range, with results corrected to the 250C.

Sampling of field water is conducted using appropriate decontaminated sample bottles supplied with appropriate additives and labelling as prescribed by NATA protocols. All plastic ware is decontaminated by storing in dilute acetic acid, with the equipment being thoroughly washed with distilled water prior to use. Field filtration is conducted by the use of 0.45 micron filter systems.

The method of sampling, including the use of blanks and replicates, and analysis methods employed are strictly in accordance with guidelines for the sampling and analysis of water and pollutants i.e. (ANZECC, 2000b and DEC NSW, 2004). In all cases, analysis methods employed are those providing adequate limits of resolution listed in (DEC NSW, 2004).


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Foybrook Formation (Open Standpipe Piezos)

-45-40-35-30-25-20-15-10-5

10/10/06 12/2/07 17/6/07 20/10/07 22/2/08 26/6/08 29/10/08 3/3/09 6/7/09

Wat

er D

epth

(mbg

l)

GCP27 GCP32 GCP34 GCP36 GCP38 R Bore

Glennies Creek Alluvium

-9

-8

-7

-6

-5

-4

-3

10/10/06 12/2/07 17/6/07 20/10/07 22/2/08 26/6/08 29/10/08 3/3/09 6/7/09

Wat

er D

epth

(mbg

l)

GCP25 GCP26 GCP28 GCP29 GCP30 GCP31

Figure 3 South Pit Extension Groundwater Levels

Head pressures within the Foybrook Formation from vibrating wire piezometer data is shown in Figure 4.


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GCP35

102030

4050607080

90100110

1/6/08 1/7/08 31/7/08 30/8/08 29/9/08 29/10/08 28/11/08 28/12/08 27/1/09 26/2/09 28/3/09

Hea

d Pr

essu

re (m

)

35(72) 35(147) 35(195)

GCP37

30

40

50

60

70

80

90

100

1/6/08 1/7/08 31/7/08 30/8/08 29/9/08 29/10/08 28/11/08 28/12/08 27/1/09 26/2/09 28/3/09

Hea

d Pr

essu

re (m

)

37(70) 37(125)

Figure 4 South Pit Extension Groundwater Pressures

As shown in Figure 5, salinity within the Foybrook Formation varies from 1185µS/cm in the shallow piezometer (GCP36), with an intake located 3m underneath the Glennies Creek alluvium, to 14,490µS/cm in the 55m deep piezometer GCP32.

The longer term trend for Richards Bore, which is located outside of the Open Cut Project Area, adjacent to Glennies Creek near the Ashton underground workings, shows a gradual salinity reduction from 7,330µS/cm to 5,000µS/cm since September 2006, reflecting the higher recharge of fresher meteoric waters due to the transition away from drought conditions. The Foybrook Formation pH generally ranges between 6.5 and 8.5,


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with the exception of the initial reading in GCP37 which had high alkalinity due to cement backfilling of the coal exploration bore (SGD602), prior to full purging of the piezometer.

0

2000

4000

6000

8000

10000

12000

14000

16000

10/10/06 18/1/07 28/4/07 6/8/07 14/11/07 22/2/08 1/6/08 9/9/08 18/12/08 28/3/09 6/7/09

Salin

ity (u

S/c

m)

GCP27 GCP32 GCP34 GCP36 GCP38 Rich B

6

7

8

9

10

11

12

13

10/10/06 18/1/07 28/4/07 6/8/07 14/11/07 22/2/08 1/6/08 9/9/08 18/12/08 28/3/09 6/7/09

pH

GCP27 GCP32 GCP34 GCP36 GCP38 Rich B

Figure 5 Foybrook Formation Groundwater Salinity and pH

Figure 6, illustrates that salinity within the Glennies Creek / Station Creek alluvium ranges from 743µS/cm in GCP28 to 20,300µS/cm in GCP31, with the higher salinities reflecting an increased proportion of clay within the alluvium, and resultant low permeability and lack of “fresh” rainfall recharge into the alluvial aquifer. The alluvium pH ranges between 6.9 and 8.9. Groundwater within the Foybrook Formation, as well as the Glennies Creek / Station Creek alluvium, exceeds the ANZECC 2000 drinking water criteria for salinity and is not suitable for drinking or irrigation use.


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02000400060008000

10000120001400016000180002000022000

31/8/07 14/11/07 28/1/08 12/4/08 26/6/08 9/9/08 23/11/08 6/2/09 22/4/09 6/7/09

Salin

ity (u

S/cm

)

GCP25 GCP26 GCP28 GCP29

GCP30 GCP31

6.7

6.9

7.1

7.3

7.5

7.7

7.9

8.1

31/8/07 14/11/07 28/1/08 12/4/08 26/6/08 9/9/08 23/11/08 6/2/09 22/4/09 6/7/09

pH

GCP25 GCP26 GCP28 GCP29

GCP30 GCP31

Figure 6 Glennies & Station Creek Groundwater Salinity and pH

4. LABORATORY INVESTIGATIONS 4.1 Bore Water Chemistry Groundwater laboratory analyses shown in Appendix C indicate that the alluvium exceeds ANZECC 2000 Freshwater aquatic ecosystem protection (95% of species) for total nitrogen, total phosphorous as well as filterable copper and zinc.

The Foybrook Formation also exceeds the same criteria for total nitrogen, total phosphorous, and can exceed the criteria for filterable copper, lead, zinc and aluminium.


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5. DATA INTERPRETATION 5.1 Hydrogeology

5.1.1 Glennies Creek and Station Creek Alluvium

Based on coal exploration and piezometer installation data, up to 14m of alluvium is associated with the Glennies Creek and Station Creek valleys.

The low conductivity surficial silty clay units can be up to 7m thick, whilst up to 6m of the higher conductivity basal gravels have been intersected. However, there is a large variability in the unit thickness, depth and formation sequence within the floodplain sediments.

The alluvium depth reduces in closer proximity to the proposed Pit as the basement underlying Station Creek crops out. Additionally, the sediments become generally more clay dominated with lesser gravels toward the proposed Pit, i.e., away from Glennies Creek.

Alluvial groundwater levels range from 5.04m to 7.67m. The levels are generally at a higher elevation than the intersected gravels which indicates the alluvial groundwater system is under hydrostatic head and the gravel aquifers are partially to fully confined.

The alluvial groundwater flow reflects the stream bed elevation fall along the creek system as shown in Drawing 4.

Pump out and falling head tests within the Open Cut Project Area indicate the alluvium is low yielding, with the maximum flow achieved being up to 0.04L/sec for up to 20 minutes before piezometer GCP32 ran dry. Hydraulic permeabilities range from 0.015m/day to 0.61m/day.

In tests conducted to the north of the Open Cut Project Area in GCP9 and GCP10 (Drawing 4) (Geoterra Pty Ltd, 2008), sufficient drawdown could not be attained to conduct a pump-out test interpretation at the maximum pump flow rate of 0.2L/sec within the 50mm casing. This indicates that higher permeabilities are present along the edge of Glennies Creek where basal gravels are more prevalent. The alluvium of Glennies Creek and Station Creek does not, however, generally provide a groundwater supply suitable for drinking, stock / domestic or irrigation use due to the low yield, high salinity and the sediment’s limited depth and extent.

No observed groundwater dependent ecosystems are present within the alluvium or its immediate discharge zone along the creek.

It is possible that groundwater discharge springs exist in the Glennies Creek bank, however none have been identified. No groundwater seepage has been observed into Station Creek to date.

5.1.2 Foybrook Formation Interburden and Coal Seams

Interburden within the Open Cut Project Area is characterised by shallow dipping, confined, low yielding, interbedded conglomerate, sandstone, siltstone, shale and mudstone units in between coal seams within the Camberwell Anticline.

Data derived from the pump out tests, packer and falling / rising head tests indicate a range of hydraulic conductivities attributed to the variation in lithologies, reducing permeability with depth of overburden and the different test methods. The testwork indicates the overburden / interburden is very low yielding, with hydraulic conductivities


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ranging from 8.64x10-7m/day in the deeper units to 4.8m/day in the 16m deep bore GCP36, whilst transmissivities range from 0.18m2/day to 0.22m2/day.

In areas where bedding dip and flexure increase or fault zones are present, the fracture / joint frequency and hydraulic connectivity through the overburden can increase compared to equivalent, undisturbed lithologies.

Due to the low yield and associated shorter duration of the pump out tests which limited the use of monitoring in observation bores, the storativity of the fractured rock and specific yield of the Quaternary alluvium was not assessed.

The coal seams planned to be mined within the proposed Pit range from the shallow subcropping semi-confined Lemington Seam in the south-west of the Pit to the confined Upper Hebden Seam between approximately 100m and 250m below surface. The seams continue along strike to the north and north-east into the now backfilled North Pit and into the proposed North Open Cut. In addition, the Integra Underground extracts the Middle Liddell Seam to the north of Glennies Creek, whilst other independent coal mine operations in the region extract all or some of the same seams.

The Lemington Seam and its underlying seams extend under the alluvium of Glennies Creek and Station Creek, however the western edge of the proposed Pit has been set back a minimum of 150m from the edge of the Station Creek alluvial system as shown in Drawing 1.

Pump out tests and packer testing indicate the coal seams are very low yielding, with hydraulic conductivities ranging from 1.037x10-2m/day to 3.456x10-4m/day.

A plot of hydraulic conductivity versus depth and formation types shown in Figure 7 indicates that the rate of hydraulic conductivity decrease with overburden depth is higher for the interburden lithologies than for the coal seams.

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

0 25 50 75 100 125 150 175 200

Depth (mbgl)

K (m

/day

)

alluv intbdn coal

Figure 7 Hydraulic Conductivity Vs Depth

During drilling, the overburden was unsaturated to approximately 3m beneath the base of Glennies Creek alluvium (GCP36), but was dry to approximately 19m (GCP37), 38m


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(GCP35) and 54m (GCP34) below surface in closer proximity to the proposed Pit.

Inspection of the South Pit highwall during April 2008 indicated that groundwater seepage flows originate from discrete horizons, at changes in lithology, and usually focussed on the upper horizon of coal seams and coarser grained units as well as from the lower section of lithological flexures in the strata. Due to evaporation, the inflows do not generate any significant ponding at the foot of the highwall during the summer months as shown in Photograph 1.

Photograph 1 South Pit (West Highwall) Groundwater Inflows

Standing water levels range from 35mbgl to 38mbgl within the proposed Pit area, and from 6.74mbgl to 44.25mbgl within the larger, Open Cut Project Area. Groundwater system depressurisation associated with the existing Integra South Pit and backfilled North Pit (which includes the Portal Sump), as well as the adjoining Rix’s Creek Open Cut, have significantly drawn down the regional piezometric surface in the vicinity of the proposed Pit as shown in Drawing 3.

No groundwater supplies are obtained from the Foybrook Formation within the Open Cut Project Area.

Seepage Collection


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5.2 Groundwater Flow A contour plan of the piezometric surface (Drawing 3) indicates that groundwater flow in the overburden, interburden and coal seams within the Open Cut Project Area is toward the South Pit, which is causing a significant depressurisation effect on the proposed Mine Area.

The local pressure gradient also indicates a distinctive groundwater flow from the backfilled North Pit and its associated Portal Sump, as well as from Tailings Dam 2 and dam D2, toward the South Pit.

A groundwater mound is indicated beneath and along the eastern bank of Glennies Creek, where a groundwater pressure gradient divide to the east and west of Glennies Creek is present, with flow to the west of Glennies Creek being toward the Ashton Open Cut and Underground operations, and along the dip of strata on the Camberwell Anticline western limb.

Localised groundwater flow also appears to be affected by strata discontinuity and/or regions of elevated permeability associated with the north-east striking fault zones that lie beneath the Glennies Creek alluvium, as well as along the channel of Glennies Creek to the west of the Open Cut Area, however there is insufficient drilling information available to definitively assess discrete flow patterns.

The Foybrook Formation water table gradient is significantly steeper in close proximity to the South Pit compared to the gradient west of Glennies Creek.

Groundwater flow within Glennies Creek alluvium is significantly different to the underlying basement. In the Glennies Creek alluvium, the alluvial pressure gradient is along Glennies Creek in a south-west direction.

Current piezometric data does not indicate a modification of the Glennies Creek alluvial groundwater flow due to depressurisation from the underlying basement and also indicates the two systems are hydraulically separate.

The overall groundwater flow pattern represents a combination of:

• potential recharge from the Glennies Creek alluvium and Glennies Creek stream channel;

• recharge from the Portal Sump and Tailings Dam 2;

• down dip flow in confined lithologies to the north-west, outside of the South Pit depressurisation zone, with minor variations due to topographical effects, and;

• unconfined alluvial groundwater flow to the south-west along the stream channel of Glennies Creek.

Flow within the Open Cut Project Area could also be modified by the effect of strata dislocation from the north easterly trending fault zones and possible flow along localised higher permeability regions within the fault zones.


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5.3 Alluvial and Foybrook Formation Test Pumping and Recovery Water Levels

5.3.1 Glennies / Station Creek Alluvium

The alluvium generally has a very low permeability, low transmissivity and low yield within the clay dominated alluvial sediments, even where gravel bands underlies the clay, with the longest test achieved being in GCP21 (Geoterra Pty Ltd, 2008A). The test lasted for approximately 11 minutes with a pump out rate of 0.16 L/sec for a drawdown of 1.8m.

Following cessation of pumping, standing water level recovery required approximately two minutes to regain the pre-test standing water level.

Alluvium yield along the edge of the Glennies Creek channel is higher, as more than 35mm of drawdown could not be achieved with the highest possible flow rate (0.18/sec) for the available submersible pump that will fit inside 50mm casing in CCP9 and GCP10 (Geoterra Pty Ltd, 2008A).


The Foybrook Formation also has very low permeability, low transmissivity and low yield, with the longest test achieved being in GCP24 (Geoterra Pty Ltd, 2008A). The test lasted for approximately 20 minutes with a pump out rate of 0.025 L/sec for a drawdown of 20.2m.

Standing water level recovery following the test was slow, with recovery to the pre-test standing water level taking in excess of 12 hours (Geoterra Pty Ltd, 2008A).

5.4 Water Chemistry

5.4.1 Groundwater

Interpretation of water chemistry analyses indicates an indistinct differentiation between the Quaternary alluvium, the Foybrook Formation and groundwater collected in the upper and lower sumps of the South Pit as shown in Figure 8. The plot indicates that the alluvium groundwater is relatively ”old” and is not significantly recharged by rain water, and is generally sodium-magnesium-chloride dominated.

Groundwater within the deeper alluvium is brackish to saline, with the high salinity attributed to a combination of lack of rainfall recharge through the very low permeability alluvial sediments as well as a potential upward leakage from the deeper Foybrook Formation.

Alluvial piezometer intakes closer to the channel of Glennies Creek exhibit lower salinity which is potentially attributable to greater recharge from rainfall and potential interconnection with Glennies Creek.

During drought periods, reduced recharge would result in declining aquifer water levels and increasing salinity, whilst the reverse would occur during extended wet periods.

Groundwater within the Foybrook Formation has a similar salinity and pH to that within the Glennies Creek and Station Creek alluvium. The coal measures have a salinity range of approximately 1,200-15,000µS/cm and pH between 6.5 and 8.5, whilst the alluvium has a salinity range of approximately 750-20,300µS/cm and pH between 6.9 and 8.9. Piezometer GCP31, which is closest to the proposed Pit and at the eastern edge of the alluvium, has the highest salinity of 20,300µS/cm.


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The coal measures groundwater is generally sodium-magnesium-chloride to sodium-chloride-sulfate dominated.

Figure 8 Open Cut Project Area Groundwater Chemistry

5.4.2 Stream Water

Stream flow within Glennies Creek has a salinity range from approximately 200µS/cm to 950µS/cm and pH from 6.2 to 9.7.

The higher salinities would be due to the higher proportional component of groundwater seepage during low rainfall periods compared to the amount of seepage into the stream after higher rainfall periods.

The salinity is also affected by the component of direct surface runoff into the stream and the degree of discharge from Glennies Creek Dam (WRM Water & Environment Pty Ltd, 2008A).

5.5 Potential Pit Void Water Quality The Pit void water salinity is highly dependent on the degree of fresh water dilution from surface water runoff, the quality of water pumped into the void from other dirty water storages across the Integra Open Cut Project Area, the salinity of water pumped from the Integra Underground and the effect of evaporation. The quality of water within the proposed Pit void will depend on the proportional contribution from groundwater seepage, spoil leachate and rainfall runoff within the void. The Pit void water will be essentially isolated from the surrounding coal measures and surficial aquifers as it will be located in a evaporative sink with an inward flowing hydraulic gradient.

LEGEND

▼ Alluvium

◊ Basement

∆ Dirty Water Ponds


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Rainfall penetrating below about 5 metres (beyond evaporative and root zone influences) will eventually migrate to the base of the Pit and leach salts in transit. Based on laboratory assessment and observation of existing water quality within the Open Cut Project Area, the waste rock is not acid generating (WRM Water & Environment Pty Ltd 2008A).

Whilst the mine is operating, all leachate will remain in the mine water system, although it would be re-circulated around the mine water management system as it is used for coal washing or dust suppression.

Representative waste rock samples were obtained from exploration drilling cores located within the proposed Mine Area. The cores were crushed into a range of grain sizes and subjected to at least 3 month long “bench top” leach trials to indicate the potential void water characteristics.

The potential void water quality was assessed to potentially be around 11,350µS/cm and approximately pH 8.5 through simulating re-saturation of the void emplacement during groundwater recovery and rainwater collection within and external to a combination of the proposed Pit and the South Pit (WRM Water & Environment Pty Ltd 2008A). The Pit void water quality will vary, however, due to the interplay between evaporative concentration, dilution from rainfall and the volume and quality of water pumped from other storages and operations within the Open Cut Project Area.

The void water is anticipated to have a sodium bicarbonate rather than sodium chloride dominated characteristic due to the high carbon content within the backfill.

5.6 Hydraulic Connection Between the Foybrook Formation and Quaternary Alluvium No upward groundwater seepage has been directly observed in the Open Cut Project Area from the underlying Foybrook Formation to the alluvium within the Glennies Creek / Station Creek catchment, although it may be occurring along the Glennies Creek channel where the Lemington and/or Pikes Gully Seams subcrop under the creek.

No direct pump out tests were conducted within the Open Cut Project Area to assess potential leakage to or from the Quaternary alluvium due to limitations on conducting the tests due to the alluvium’s very low yield and shallow depth combined with the low permeability of the Foybrook Formation.

Monitoring of standing water and groundwater chemistry of the strata beneath the alluvium to date does not directly indicate observable recharge from the alluvium to the underlying Foybrook Formation, or upward leakage from the underlying strata to the Glennies Creek alluvium. However, as noted in Section 2.6.2, natural recharge of the coal measures from the Glennies Creek alluvium was postulated at approximately 2L/sec (62ML/year) to the Pikes Gully Seam in the Ashton Underground Longwall 1 area. Following extraction of Longwall 4, it is estimated that total inflows to the Ashton Underground could range from 0.4-3.4L/sec (13.9-106ML/yr) (P Dundon & Assoc. 2006).


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5.7 Connected and Disconnected Alluvium Zones To Glennies Creek

In order to assess the potential hydraulic connection between the alluvial aquifer along Glennies Creek and its potential for baseflow recharge to Glennies Creek, the relevant results from field investigations within both the Underground Project Area and the Open Cut Project Area (Geoterra, 2009) have been summarised in Table 6.

“Baseflow” is defined as the contribution of groundwater that sustains flow in a stream, whilst “quickflow” is the direct and short term response to rainfall that includes flow over the land surface (overland flow or runoff).

Rapid lateral movement into the soil profile is defined as “interflow”. The relative contribution of quickflow and baseflow changes throughout a stream hydrographic record with changing rainfall patterns.

Table 6 Glennies Creek Alluvium Features

Bore

Dist to Glennies Creek (m)

Alluvium TD (m)

SWL (mbgl)

Saturated Thickness (m)

10% Saturation Trigger (m) EC (uS/cm) pH K (m/day)

Well Connected To Glennies Creek GCP9 35 9 4.59 4.41 0.44 413 7.3 10

GCP10 45 11.5 6.27 5.23 0.52 579 7.13 10 Less well Connected To Glennies Creek

GCP25 60 13 6.11 6.89 0.69 307 7.61 0.04 GCP28 175 12 6.28 5.72 0.57 823 7.48 0.17

GW67291 50 10.3 8.13 2.17 0.22 1150 7.27 _ GCP21 175 11 7.6 3.4 0.34 1674 7.37 0.16 GCP19 340 12 8.44 3.56 0.36 2180 7.18 _ GCP30 345 12 5 7 0.70 5980 7.25 0.06 Poorly Connected To Glennies Creek GCP29 690 10 5.94 4.06 0.41 6540 7.14 0.61 GCP26 760 11 4.94 6.06 0.61 13310 7.5 0.016 GCP22 305 12 6.23 5.77 0.58 15150 7.18 0.03 GCP23 390 8 6.11 1.89 0.19 16070 7.4 0.06 GCP31 830 14 7.54 6.46 0.65 19560 7.16 0.1

Not Connected GCP20 530 8.2 dry dry dry dry dry dry

Plots of distance from Glennies Creek versus alluvial groundwater salinity, hydraulic conductivity and pH are shown in Figure 9. The plots indicate there is a reasonable to good relationship between increasing salinity and increasing distance from Glennies Creek and a reasonable relationship between hydraulic conductivity (permeability), which is determined by the gravel and sand component in the alluvium, and distance from the creek. There is a poor relationship between pH and distance from the creek.

When assessing the distance / salinity / hydraulic conductivity relationship and the peak / trough responsiveness of monitored groundwater levels to varying rainfall and stream flow heights, combined with their elevated hydraulic conductivity, it is clear that the Quaternary alluvium in the vicinity of GCP9 and GCP10, to the north and upstream of the Open Cut Project Area, is in direct connection with Glennies Creek. These piezometers were completed in coarse, sandy, clayey gravels at the base of the alluvium.


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It is assessed that similar hydrogeological conditions are present in the closely connected alluvium along Glennies Creek within the Open Cut Project Area, however, due to limited available access, equivalent piezometers to GCP9 and GCP10 were not installed in close proximity to the creek.

With increasing distance away from the creek, the Quaternary alluvium becomes more clay dominated, with lower permeability sediments in the more distal to peripheral areas of the alluvium. The distal, clay dominated areas were deposited where stream flow was not as active compared to the depositional facies in the main channel. The clay dominated sediments were deposited in overbank deposits or billabongs outside of the main stream flow.

It is interpreted that alluvium in the vicinity of Station Creek represents a buried tributary palaeochannel of Glennies Creek that is potentially hydraulically seperated, or partially seperated, from the alluvial system of Glennies Creek.


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R2 = 0.4062

0.01

0.1

1

10

0 100 200 300 400 500 600 700 800 900

Distance to Glennies Creek (m)

Hyd

raul

ic C

ondu

ctiv

ity (m

/day

)

R2 = 0.0371

7.1

7.2

7.3

7.4

7.5

7.6

7.7

0 100 200 300 400 500 600 700 800 900

Distance to Glennies Creek (m)

pH

Figure 9 Glennies Creek Alluvium Salinity, Hydraulic Conductivity and pH Vs Distance From Glennies Creek

Assessment of lithologies and groundwater gradients between GCP26 and Glennies Creek as shown in Figure 10, indicates a gradient of 0.0036 between GCP26 and Glennies Creek, with a calculated Darcy travel time of over approximately 1,000 years over the 760m distance through the clay and clayey gravel dominated basal sediments, on the basis that flow is toward Glennies Creek, and is not short circuited to the Station Creek system.

Based on the assessments and data summarised in this section, it is interpreted that alluvium;

• dominated by low permeability clay basal sediments are assessed to be poorly connected to Glennies Creek, such as at GCP26, GCP29 and GCP31

• alluvium containing low to moderate permeability, basal, clayey gravels is less well connected to Glennies Creek, such as at GCP28 and GCP30), whilst;


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• alluvium, as characterised by piezometers GCP9 and GCP10, which are located on a lower alluvial terrace and contain high permeability basal gravels, is well connected to Glennies Creek and provides baseflow to the creek.

55

60

65

70

75

80

85

90

0 100 200 300 400 500 600 700 800 900 1000 1100 1200

Distance (m)

Heig

ht (m

AHD)

surface AHD clay base grav base swl

Figure 10 Glennies Creek Alluvium Cross Sections and Groundwater Profiles

As an extension of the field and office work conducted to date, it is extrapolated that the well connected areas along Glennies Creek are characterised by high permeability basal gravel sediments, which are primarily contained within the extent of the lower alluvial terrace. The “well connected” zone will vary in its areal extent depending on the distribution of the high permeability gravels. However, as an initial indication, where the terrace is absent or not well developed, the connected alluvium is assessed to be located within 200m of the creek edge.

This zonation can be further defined as and where required with further field studies.

GCP27 GCP26

EAST WEST


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6. GROUNDWATER MODELLING The model structure and modelling approach, model calibration, results of the simulations and sensitivity analyses are detailed in Appendix D, along with assessment of the potential impacts which are summarised in the following sections.

The scenarios developed as knowledge of the regional hydrogeology improved. The modelling was carried out on the understanding that this investigation is preliminary in nature, with the model constructed to represent the Open Cut Project Area based on reasonable and representative assumptions, despite limited data availability.

The assumptions and the conclusions that follow from the model analyses reflect these understandings and assumptions.

Due to limited temporal groundwater data, transient calibration of the model was not conducted, although verification of predicted and observed groundwater levels and confirmation of hydraulic conductivities was undertaken through comparison to similar groundwater assessments in the local area.

Although there is also some uncertainty over the level of interaction and hydraulic connection between layers and the hydraulic conductivity estimates applied to the formations, the model has used currently available data and the most recent understanding of the model area hydrogeology to simulate the groundwater system in the vicinity of the proposed Pit.

It should be noted that although this report focuses on the results of modelling the proposed “Full” Pit, the model was set up to address the concurrent issues of mining the proposed Pit, multi seam mining in the Middle Liddell, Hebden and Barrett Seams at the Integra Underground and simultaneous mining at other open cut and underground mines in the local area.

The numerous Integra and other unaffiliated open cut and underground mines in the model area all hydrologically interact, and it was not valid to model the effect on the local groundwater system around one operation without incorporating the interference effects from nearby operating (and proposed) mines.

A full discussion of the effects due to the potential Barrett / Hebden seam underground mining is contained in a separate report.

6.1 Conceptual Hydrogeological Model A conceptual understanding of the hydrogeology of the Open Cut Project Area provided a basis for a numerical groundwater model using the FEFLOW package (Version 5.2).

The stratigraphy within the model can be divided into essentially dry shallow overburden which changes to very low yielding overburden with depth down the stratigraphic column and down dip to the north-west and west of the proposed Pit.

Active and decommissioned open cut and underground coal mines are located both up and down dip of the proposed Pit which have depressurised, and will in the future, continue to depressurise the groundwater system within the proposed Open Cut Project Area. Hydraulic connection is also present between the current South Pit and, to a lesser degree, the backfilled North Pit void and the proposed Pit, which has the effect of reducing potential future inflow rates into, and reducing the effective regional depressurisation potentially caused by the proposed Pit.


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Hydraulic permeabilities and yield in the coal seams, overburden and interburden may potentially be enhanced in regions of faulting or structural discontinuities within the proposed Pit. However, as the exact location and effective permeability of these structures is not known at this stage, the effect on pit inflow volumes may need to be revised as further information on their location and nature is available as mining progresses.

Analysis of measured standing water levels in piezometers indicate that the current flow in the confined coal seams is essentially toward the South Pit within the Open Cut Project Area, whilst it is to the north-west on the western side of Glennies Creek. It is also observed that groundwater flow in the Open Cut Project Area is not significantly affected by topographical effects as the presence of existing (and proposed) open cut and underground coal mines dominate the groundwater system in close proximity to the proposed Pit.

6.1.1 Integra Mining Schedule

The anticipated mining schedule within both the Integra Open Cut Project Area and the Integra Underground lease area is schematically illustrated in Figure 11.

Year 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

South Pit

North OC

Proposed Pit

MLS LW 8-17

Hebden UG

Barrett UG

NOTES: 08 Groundwater Model Run MLS LW Middle Liddell Seam Longwall

Open Cut Mining

UG Longwall Mining Only

UG Longwall Mining Plus Intermittent Cut / Flit Mining

UG Drift Construction

UG Bord and Pillar Mining Only

Figure 11 Anticipated Integra Mining Operations

6.1.2 Recharge

Recharge to the Foybrook Formation in the vicinity of the proposed Pit is assessed to primarily occur along the major creeks, within the creek alluvium and generically across the outcropping coal measures, with the predominant recharge occurring within the creek alluvium.


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It is also possible, based on regional information, that basement groundwater may be up-welling into the base of the alluvial channel of Glennies Creek, however an actual rate and location of upwelling has not been identified to date with current data. Considering the essentially low permeability, porous character of the bedrock, it is likely that hydraulic connection between the alluvium and the bedrock would preferentially occur within more discrete, fractured zones which would provide preferential pathways for groundwater flow. The potential magnitude of stream bed leakage resulting in groundwater recharge between the alluvium and bedrock has been estimated at this stage as no direct measurement could be conducted.

The magnitude of creek induced recharge during wet spells and erratic flood events has not been established to date due to the lack of long term monitoring along with the lack of sufficient high rainfall events within the monitoring period. However, the understanding of the rate of recharge in relation to wet spells and flooding can be developed with on-going monitoring.

To address the uncertainty related to the recharge mechanisms and magnitudes and relationship between Quaternary and underlying systems, ongoing groundwater level and stream flow monitoring is required, followed by refinement of the conceptual model if required when new data is available.

6.2 Modelling Code The model was developed using FEFLOW package (Version 5.2), which was developed by the WASY Institute for Water Resources Planning and Systems Research, Berlin, Germany.

FEFLOW has become an industry standard in the context of finite element models for groundwater flow and mass and contaminant transport simulations.

6.2.1 Model Structure

The model mesh was generated using the advancing front method, with mesh refinement carried out within and around the footprint of the proposed Pit and other mines in the model area where increased detail was required in order to ensure that flow processes were adequately accommodated.

The spatial extent of the model was developed as shown in Figure 12.


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Figure 12 Model Extent

The model consists of 11 layers.

• Layer 1 - alluvial deposits along the major creeks and weathered bedrock outside the alluvial channels to 8m below surface across the model, with the Quaternary alluvial channels represented by increased hydraulic conductivities to segregate them from the lower conductivity hillslope colluvium and outcropping weathered basement;

• Layer 2 - weathered bedrock, with a uniform thickness of 20m across the model (to 28m below ground surface). The layer corresponds to the assumed base of post longwall subsidence based surficial fracturing;

• Layer 3 - overburden extending from the base of surface fracturing zone to 150m above the Middle Liddell Seam;

• Layer 4 - overburden from 150m above the Middle Liddell Seam to 30m above the Middle Liddell Seam;

• Layer 5 – from 30m above the Middle Liddell Seam to the Middle Liddell Seam;

• Layer 6 - the Middle Liddell Seam with a layer thickness of 3m;


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• Layer 7 - interburden between the Middle Liddell Seam and the Barrett Seam;

• Layer 8 – the Barrett Seam, with a nominal thickness of 8m;

• Layer 9 – interburden between the Barrett and Hebden Seams;

• Layer 10 – Hebden Seams with nominal thickness of 8m, and;

• Layer 11 – bedrock beneath the Hebden Seams with a nominal thickness of 150m.

A cross-section showing the distribution of layers is presented in Figure 13.

FEFLOW groundwater modelling assumed that mining will commence in the middle of the Full Pit and progress to the north up to the 4th year of mining, and then will relocate to extract the remaining southern portion up to the 8th Year of mining. Other mine extraction scenarios may develop during extraction of the Full Pit. However, although the transient changes may differ during the period of extraction, the final end-of-pit depressurisation will generate the same effect on the groundwater system around the proposed Pit as has been modelled in this study.

The true recharge distribution over the modeled area is unknown. Based on the conceptual model and the analysis of measured groundwater heads, it was assumed that the main recharge areas for the Foybrook Formation would be located along alluvium associated with the major creeks. Creeks were represented to allow for seepage into or removal from the system.

Pit dewatering was represented by boundary conditions which simulated deepening of the excavation combined with temporal changes of hydraulic conductivity to represent the Pit void. The boundary conditions were limited by appropriate constraints allowing for inflow of groundwater only into the Pit sump. Hydraulic conductivity values used in the model were based on field test measurements shown in Table 7.

Table 7 Parameters Used in the Proposed Pit Model

Formation Horizontal Hydraulic

Conductivity (m/s)

Pre / Post Subsidence

Vertical Hydraulic

Conductivity (m/s)

Pre / Post Subsidence

Specific Yield

/ Storage

S y/ Ss (l/m)

Recharge

(mm/yr)

Alluvium (0-8mbgl) 9.2 x 10-7 / 5.8 x 10-5 4.6 x 10-7 / 2.9 x 10-5 0.20 / - 4.5 / 8

Weathered Rock (8-28mbgl) 1.0 x 10-8 1 x 10-9 0.005 / 5 x 10-6 0

Fresh Sandstone / Shale 1.0 x 10-9 1 x 10-10 0.005 / 5 x 10-6 0

Middle Liddell Seam (Shallow / Deep) 1.8 x 10-7 / 4.1 x 10-9 1.8 x 10-8 / 4.1 x 10-10 0.03 / 5 x 10-6 2.2 x 10-5 / -

Interburden 1 x 10-9 1 x 10-10 0.005 / 5 x 10-6 0

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Hebden Seam (Shallow / Deep) 4.0 x 10-9 / 4.0 x 10-10 4.0 x 10-10 / 1.9 x 10-10 0.03 / 5 x 10-6 2.2 x 10-5 / -

Pit Backfill (operational) 1.0 x 10-3 No change 5 x 10-6 -

Post backfill / Pit Lake 1.0 x 10-4 / 1.0 x 10-3 0.2 / 0.99 5 x 10-6 -


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Figure 13 Model Cross Sections

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At the time of conducting the modelling, no data was available on storage parameters of modelled strata, and therefore values of specific yield and specific storage adopted in the model were based on available published values as well as from similar modelling exercises within NSW coalfields.

The model run simulated 9 years of mining and 23 years of post-closure conditions, with the time frames chosen based on the anticipated mining operations within the Integra Open Cut and Integra Underground lease areas.

It was assumed that hydraulic conductivity within the proposed Pit void during excavation equated to 1.15x10-3m/sec followed by 1 x 10-4m/sec after backfilling, allowing for essentially unrestricted groundwater movement within the void during and after excavation compared to conditions outside the pit. Both assumed values are substantially higher than the initial hydraulic conductivity in the Mine Area strata.

6.3 Sensitivity Analysis A sensitivity analysis was carried out to address the uncertainty of model parameters and implications for resulting model predictions as outlined in Appendix D. Two cases were modelled.

Case 1 involved assessment of the model sensitivity to changing permeabilities in the shallow strata under the alluvium following longwall subsidence at the Integra Underground compared to un-subsided areas or areas under bord and pillar mined sections where limited to no subsidence will develop. Case 2 involved changing the alluvium permeability to assess what effects that may cause on drawdown and seepage to the local streams over and adjacent to longwall subsided and bord and pillar areas as well as adjacent to the proposed Pit. Case 1 involved varying the hydraulic permeability of the strata under the alluvium, while Case 2 involved decreasing the alluvium permeability in accordance with observed field data.

The sensitivity analyses results indicate the following.

• Case 1 – Greater drawdowns and a greater reduction in seepage to the local streams occurred in the alluvial aquifers for higher permeabilities within the shallow basement underlying the alluvium in underground mining areas if subsidence cracking over the bord and pillar areas is present.

• Case 2 - Lower permeabilities in the alluvium significantly reduce the degree of drawdown in the alluvial aquifers and reduce the loss of seepage to local streams.

6.4 Model Calibration Due to the complex interactive depressurisation effects of numerous coal mines on steady state groundwater levels within the model area, calibration of the model was more focussed on obtaining correlation between known and modelled mine inflow rates, as opposed to matching observed and modelled groundwater levels. Discussion of the root mean square (RMS) is therefore limited as the model was not calibrated to water levels, mainly due to the lack of time variant groundwater extraction data, which affects groundwater levels.


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To validate the model generated outputs, model generated inflow rates were compared to modelled and observed mine inflows for the Mt Owen, North Open Cut, South Pit, North Pit, Glendell Pit and the Ashton Underground.

Calibration of the model did achieve a good correlation of the modelled and known mine inflows as well as reasonable agreement with measured groundwater levels.

Modelling outputs suggest the steady state groundwater head is, in general, higher than the measured heads within the Foybrook Formation, with overall gradients in the model matching the measured data.

It is concluded that higher than observed groundwater heads in the model would result in a conservative estimate of the impact of dewatering on the surrounding groundwater regime and that the higher post-subsidence shallow coal measure permeabilities in the Integra Underground Lease Area and the higher alluvium permeabilities overestimate the alluvium drawdown and the reduction in seepage to local streams.

In the vicinity of the proposed Pit, the match of modeled and measured groundwater heads for the low hydraulic conductivity case was satisfactory, but the overall hydraulic gradients in the model are flatter than those indicated from field data. Attempts to improve the calibration with respect to these gradients were unsuccessful suggesting that the uniform hydraulic conductivity distributions applied within the model to represent strata may be too simplistic to allow a more detailed simulation of field conditions.

6.5 Potential Impact on Local Groundwater Systems and Groundwater Users of the “Full Pit”

Excavation of the “Full” Pit will depressurise the local groundwater environment, with the potential impacts discussed in the following sections, including:

• a reduction in regional aquifer pressures during mining;

• minor to negligible leakage of groundwater from alluvial lands adjacent to the proposed Pit,

• salinity reduction in the alluvial groundwater system; and

• rising Foybrook Formation aquifer pressures after mining is completed.


Mining of the proposed Full Pit will generate a groundwater pressure reduction that will combine with pressure reductions generated by adjacent Integra and non-affiliated open cut and underground mines in the local area.

Extraction will progressively depressurise the various coal seams and overburden as the pit deepens. As predicted by modelling, the loss of aquifer pressure will migrate along the strata, away from the Mine Area, then progress upwards through the overburden via interstitial porosity.

Since the hydraulic conductivity of the un-mined overburden is very low, depressurisation within strata adjacent to the Mine Area will have a steep sided surface around the perimeter of the proposed Pit as is evident at other similar mines in the region. Seepage to the proposed Pit is predicted to be low and consistent with historical mining in the South


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Pit, which has an average (post evaporation) pump out rate of 0.02ML/day.

Operation of the proposed Pit would draw down the piezometric surface around, and centred on, the Mine Area within the confined Hebden Seam and overlying seams during mining as shown in Figures 14 to 17, with the water table gradually returning, albeit to a lower level in the immediate vicinity of the proposed Pit due to enhanced evaporation.

There are no active DWE registered bores that extract groundwater from within the Open Cut Project Area, and therefore drawdown caused by the proposed Pit will not cause any adverse impact on private bores within the Open Cut Project Area.

Figure 14 Hebden Seam Drawdown, Year 2014

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The hydraulic parameters of fault zones within the Open Cut Project Area are unknown at this stage. If the hydraulic conductivity of the faults is higher than the surrounding strata, they may act as water conduits resulting in higher inflows into the proposed Pit. By contrast, albeit unlikely, if the hydraulic conductivities of the faults are lower than the surrounding strata, they may act as barriers which could result in lower than estimated inflow rates into the Pit.


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6.5.2 Quaternary Aquifers

Modelling indicates that the cone of depression within the Foybrook Formation would not develop significantly outside of the immediate vicinity of the proposed Pit. However, there will be additional drawdown to the north of the proposed Pit, after the Pit is completed, through depressurisation connection around the Ashton Coal Operations Barrett Pit as well as the longwall operations in the Middle Liddell Seam and Barrett / Hebden Seam workings at the Integra Underground.

Upward progression of the cone of depression from the underlying Foybrook Formation into the clay based Quaternary alluvium would be restricted due to the low permeability of the sediments.

The footprint of the proposed Pit provides a buffer zone for the alluvial lands associated with Station Creek and Glennies Creek with the Mine Area located such that no Quaternary alluvial aquifers will be mined. The proposed Pit is located a minimum of 150m east of the Station Creek Quaternary Alluvium, and approximately 600m east of the Glennies Creek channel.

Loss of pressure within the coal measures has the potential to indirectly affect groundwaters within the alluvial lands by lateral and vertical leakage through interstitial strata porosity.

The current hydrogeologic regime has elevated pressures within coal measures that are closer to Glennies Creek, as opposed to Station Creek, which can dissipate through upward leakage into the low lying alluvial aquifer along Glennies Creek. This flow regime leads to a generally brackish or saline environment in basal sections of the alluvium.

Improved quality groundwater mostly occurs at shallow depths through the downward migration of rainfall recharge.

Post mining reductions in the Foybrook Formation groundwater pressure has the potential to reduce the rate of upward leakage into the alluvium and could reverse upward flows depending upon the vertical permeability of the weathered interburden zones under the alluvium. Improved quality groundwater from rainfall recharge may then migrate to greater depth within the alluvium as saline groundwater is displaced downwards. The extent to which this process could develop is difficult to predict beyond a general concept since sustained flushing would be required to improve the deeper saline groundwater environment within the alluvium.

Groundwater within alluvial aquifers associated with Glennies Creek and Station Creek would be marginally to negligibly affected by the proposed Pit during its active mining phase, with drawdowns ranging up to 1.2m (based on the Case 1 groundwater model hydraulic conductivity of 7.9 x 10-2m/day) in the vicinity of the Mine Area until mining of the pit is completed in 2018.

Drawdown in the alluvium to the west of the proposed Mine Area gradually increases after the proposed Pit is completed to reach a maximum of between 0.5m (GCP28) and 3m (GCP31) in 2041. To the north of the Mine Area, the drawdown increases after the proposed Pit is completed, particularly in GCP26 as shown in Figure 18, due to depressurisation originating from Integra’s proposed underground mining within the Barrett Seam which is planned to occur between 2024 and 2031. Piezometer GCP26 is modelled to potentially have up to 7m of drawdown. It should be noted that GCP26 is,


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however, located approximately 800m east of Glennies Creek in the “disconnected” alluvial zone.

The groundwater level depression is higher within piezometers that are closer to the proposed Pit and the proposed Barrett Underground, with the drawdown reducing in closer proximity to Glennies Creek.

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2008 2013 2018 2023 2028 2033 2038 2043

draw

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n (m

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GC25 GC26 GC28 GC29 GC30 GC31

Figure 18 Modelled Alluvium Drawdown Near The Proposed Pit

Current groundwater level monitoring indicates a gradient toward Glennies Creek, apart from GCP30 to GCP31, where the limited, current data indicates a gradient toward the proposed Pit area.

In 2018, when the mining in the Extended South Pit has finalised, there will be a similar, albeit slightly reduced, post mining gradient toward Glennies Creek between GCP26 and GCP25, as well as between GCP29 and GCP28, compared to pre-mining. The pre-mining gradient groundwater flow away from Glennies Creek between GCP30 and GCP31 will be maintained, although reduced, as shown in Table 8.

Modelling indicates the alluvium depressurisation will be less than 10% of the saturated aquifer thickness.

Table 8 Glennies Creek Alluvium Groundwater Gradient

Stretch 2008 Pit Water Level Gradient (m)

2008 Flow Direction 2018 Water Level Gradient (m)

2018 Flow Direction

GCP26 to GCP25 1.88 / 900 To Glennies Creek 1.71 / 900 To Glennies Creek

GCP29 to GCP28 2.06 / 500 To Glennies Creek 1.65 / 500 To Glennies Creek

GCP30 to GCP31 1.06 / 470 To the east 0.84 / 470 To the east


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Figure 19 indicates that the current loss of flow from Glennies Creek due to depressurisation, on both sides of Glennies Creek between the confluence with Main Creek and the dogleg in the creek adjcent to Bore GW80968 (Drawing 2), is currently modelled at approximately 0.008ML/day (2.92ML/year).

In the same reach, after mining in the Extended South Pit is completed, the loss of stream flow is modelled to rise to approximately 0.01ML/day in the Year 2018.

Depressurisation in the Quaternary alluvium, and loss of flow in Glennies Creek after 2018 is due to the additional effect of other mining operations within the reach area, as the proposed Pit will have reached its maximum depth at that time.

The change in modelled loss out of Glennies Creek streamflow from the current 3.1ML/year to an outflow of approximately 4.2ML/yr in 2018 following cessation of mining in the proposed Pit as shown in Figure 19 will generate a minor, inconsequential change to the stream flow of Glennies Creek.

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Figure 19 Modelled Flow Loss from Glennies Creek

There are 13 registered water extraction points between Nobles Crossing and the confluence with Station Creek for both general and high security licences, as well as stock, domestic and supplementary use, which can extract up to 1018ML/year in that stretch of the creek. The reduction in Glennies Creek stream flow as a consequence of the 0.02ML/day (7.3ML/year) change in alluvial groundwater seepage to the creek due to mining the proposed Pit is insubstantial compared to the allocated stream water extraction within the reach between Main Creek and adjcent to Richards Bore (GW80968).

The change over the life of the proposed Pit in seepage rate from the alluvium into Glennies Creek is considered minor and manageable, particularly when compared to the flow range within Glennies Creek, which exhibits a mean flow of 179ML/day at the Middle Falbrook Road bridge (WRM Water & Environment, 2008).

The sequential drawdown in Layer 1 of the model, which represents the alluvium, is shown in Figures 20 to 23.

Cessation of mining in the proposed Pit


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Figure 20 Modelled (Layer 1 ) Alluvium Drawdown, Year 2014

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6.6 Potential “Full” Pit Inflows It is predicted that excavation of the proposed Pit may generate low inflows to the pit due to the low yields and low transmissivities of the coal seams, interburden and overburden within the Open Cut Project Area, albeit with an increasing annual inflow up to approximately Year 2018 as the pit deepens.

Inflows range from approximately 36.5ML/year within the current South Pit up to 117ML/year at the end of mining the proposed Pit as shown in Table 9.

It should be noted that the quoted inflows do not incorporate the loss of water due to evaporation, which would significantly reduce the actual amount of stored water as the average annual evaporation (1613mm/year) is approximately 2.3 times the annual rainfall of 660 to 735mm/yr.

Table 9 Potential Proposed Pit Groundwater Inflows (Without Evaporation)

Year Modelled Pit Inflow Rates

L/sec m3/day ML/day ML/year

2008 (Current South Pit) 1.16 100 0.1 36.5

2014 2.31 200 0.2 73

2018 3.70 320 0.32 117

Previous studies (MER, 2003) estimated that up to 70% of groundwater inflow to the proposed Pit may be lost as evaporation, while anecdotal experience from operating the South Pit (C. Smith, pers comm.) indicates that the current South Pit does not have significant observable groundwater inflows.

6.7 Post Mining “Full” Pit Void Water Levels Once mining and pumping from the completed proposed Pit ceases, the regional aquifer pressures will recover. The rate and degree of recovery are dependent upon the remaining water held in storage within the adjoining coal measures, as well as the hydraulic properties of adjacent strata, recharge from rainfall as well as the rate and volume of water pumped into the void from other Integra operations.

An estimate of the post mining regional rate of recovery of groundwater pressure has been made using the aquifer simulation model in Appendix D with an interpreted groundwater inflow of 117ML/year to the final void, prior to evaporation.

Rainfall and runoff that may be captured within the void is estimated to range from 461ML/yr in Year 4 to 384ML/yr in Year 8 of mining (WRM Water & Environment, 2008A).

Refilling of the void involves groundwater and surface water inflow as well as losses from the open water body due to evaporation of any exposed void water. In addition, the proposed Pit is also currently identified for use as a dirty water storage once mining is completed, which will raise the standing water level to a level determined by the quantity of water pumped into the void.

The combined groundwater inflow and surface water capture in the final void will generate a final pit void lake that will reach approximately -50m RL, and will contain


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around 7000ML, with the lake elevation being dependent on a range of operational issues that will apply after mining is completed (WRM, 2008).

A sensitivity analysis (WRM, 2008) indicated that even if the modelled evaporation rate was reduced by 30%, the final void water level would rise to around 20m below the natural ground surface after approximately 1000 years, and therefore it is anticipated that the final void will not spill water.

7. POTENTIAL “FULL PIT” WATER QUALITY IMPACTS 7.1 Potential Salt / Contaminant Migration Pathways It is not anticipated that an increase in salinity levels in Glennies Creek will occur due to groundwater effects from mining the proposed Pit as:

• the cone of depression around the final void will generate an inward flowing groundwater system toward the pit;

• the pit will not overflow (WRM Water and Environment, 2008)

• partial depressurisation of the Glennies Creek alluvium may potentially increase the recharge of fresh rainwater into the alluvium and lower the salinity of the alluvial aquifer

Based on the lack of anticipated groundwater flow effects on stream salinity, solute transport modelling is not considered necessary. Salt generation through rainfall recharge within the backfilled waste will occur, although this will be confined within the final void and will be used in the Integra dirty water system. However, it is not anticipated that salt or any other potential contaminants would be transported off site via the groundwater system due to the inward flowing cone of depression.

Off site migration of contaminants via the surface water system would be contained within the mine’s dirty water management system. The reader is referred to the surface water study (as part of this EA assessment) for further detail on this aspect.

7.2 Potential Impacts on Regional Groundwater Quality Dewatering associated with the proposed Pit is not anticipated to have an adverse impact on groundwater quality within the Foybrook Formation.

Modelling indicates that the deepest groundwater level declines will occur in close proximity to the proposed Pit, with the cone of depression rapidly shallowing away from the pit. On this basis, the leaching of salts will be confined to the active pit and final void.

No observable change in water quality due to groundwater drawdown is anticipated in private bores or wells as there are no bores or wells within or near the Open Cut Project Area.

7.3 Potential Impacts on Regional Surface Water Quality No adverse effect is anticipated on surface water quality in Glennies Creek or Station Creek due to groundwater movement as the Quaternary alluvium depressurisation does not extend as far as the channel of Glennies Creek within Layer 1 or Layer 2 of the model.

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anticipated to extend up into Glennies Creek.

To date, no groundwater seeps have been observed within the Glennies Creek or Station Creek.

7.4 Potential Final Void Water Quality Results from waste rock batch leach testing and acid rock drainage studies were incorporated with the potential groundwater inflows, clean water in-pit rainfall and runoff, tailings dam leachate and evaporation from the final void water body to assess the potential final void water quality that may develop within the Extended South Pit after it is rehabilitated. The initial studies indicate the final void will have a water quality of approximately pH 8.5 and salinity of 11,350µS/cm.

However, the final void water quality will be highly dependent on the degree of clean water dilution provided from surface runoff and the degree of evaporation.

Based on analyses of similar water bodies within the Integra Complex, the final void water may also exceed the ANZECC 2000 criteria for Protection of 95% of Freshwater Species for total nitrogen, total phosphorous as well as copper and zinc (WRM Water & Environment, 2008), and will therefore not be discharged to local streams.

The potential effect of addition of water pumped from other storages or mining operations within the combined Integra Open Cut and Integra Underground water management system is not included in this assessment as the actual input from other sources is not yet known.

8. POTENTIAL “FULL PIT” IMPACT ON STREAM FLOWS AND GROUNDWATER DEPENDENT ECOSYSTEMS

8.1 Local Creeks It is not anticipated that stream flow in Glennies Creek or Station Creek will be observably affected by mining the proposed Pit, as modelling indicates a minor loss in flow from the current 3.1ML/year up to 4.2 ML/year at the end of mining the proposed Pit.

It is considered likely that Glennies Creek is currently recharging the Foybrook Formation as no springs or seeps into creeks within the Open Cut Project Area have been observed to date.

Due to the elevated groundwater salinity and potential final void salinity, it is not proposed to discharge site water into the local surface water system.

It is not anticipated that the Open Cut Project Area site surface water storage capacity will be exceeded due to the low inflow rates to the proposed Pit, low rainfall and high evaporation in the area (WRM, 2008).

8.2 Potential Impacts on Groundwater Dependent Ecosystems No groundwater dependent ecosystems (GDEs) have been identified within the Open Cut Project Area, and therefore there are no anticipated adverse effects on GDEs.


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9. POTENTIAL GROUNDWATER IMPACTS OF THE PART PIT The Full Pit represents a worse case scenario compared to the Part Pit scenario in terms of regional and local effects on the Open Cut Project Area groundwater system.

Extraction of the Part Pit as opposed to the Full Pit will marginally reduce the degree and northerly extent of regional groundwater depressurisation within the basement and alluvial aquifers in the vicinity of the proposed Pit. In addition, the Part Pit void inflow volumes will be marginally reduced, as will the timeframe over which the depressurisation effects occur.

If the Part Pit is only extracted, the Dulwich property will remain in an unmined state, but significant basement depressurisation will still occur within the property. However, as no registered groundwater bores are used to supply water to the property, nor is there a potential for beneficial use due to the poor groundwater quality, there will be no adverse effects on the property owner’s existing or potential groundwater supply.

10. MONITORING, REHABILITATION, CONTINGENCY MEASURES AND REPORTING

10.1 Monitoring

10.1.1 Standing Water Level

Open standpipe piezometers to be included in the Open Cut Project Area groundwater level monitoring suite include GCP27, 32, 34 and 36, along with vibrating wire piezometers installed in GCP35 and GCP37 within the Foybrook Formation.

Alluvial groundwater levels will be monitored by open standpipe piezometers GCP25, 26, 28, 29, 30 and GCP31, which are located along Glennies Creek and Station Creek.

The location of all groundwater monitoring points presented in Drawings 3 and 4.

Water level transducers and loggers are currently, or will be, used to twice daily monitor water levels and assess variations in the alluvial and Foybrook Formation aquifers in the following piezometers;

• Alluvium - GCP26, 29, 30, 31 (open standpipe piezometers)

• Foybrook Formation - GCP27,32,34,36,38 (open standpipe piezometers)

• Foybrook Formation – GCP35, 37 (vibrating wire piezometers)

Monitoring will also involve bi-monthly manual standing water level measurement in all piezometers not containing automatic loggers within the Open Cut Project Area suite, along with downloading and re-initiation of the loggers as shown in Table 10.


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Table 10 Standing Water Level Monitoring Method and Frequency

Monitoring Suite Sampling Method Frequency Units

GCP26, 29, 30, 31 Water level logger / dip meter twice daily / bi-monthly mbg

GCP26, 28, 29, 30, 31 dip meter bi-monthly mbg

GCP27, 32, 34, 35, 36, 37, 38 Water level logger / dip meter twice daily / bi-monthly mbg

GCP27, 32, 34, 36, 38 dip meter bi-monthly mbg

GW67291, GW80968 dip meter bi-monthly mbg

Note: mbg = meters below ground

10.1.2 Groundwater Quality

Table 11 present the groundwater quality parameters to be measured, frequency of monitoring and sampling method.

Table 11 Groundwater Quality Monitoring Parameters

ANALYTES Units FREQUENCY

EC, pH µS/cm, pH units bi-monthly

(EC, pH) + TDS, Na, K, Ca, Mg, F, Cl, SO4, HCO3, NO3, Total N, Total P, hardness, Cu, Pb, Zn, Ni, Fe, Mn, As, Se,

Cd, Cr (Totals)

µS/cm, pH units + mg/L Annually

The frequency of monitoring will be reassessed after mining is complete as it may be possible, depending on results, to lengthen the intervals. Similarly, the frequency of monitoring and the analytes to be monitored may be varied in consultation with DWE and the Department of Environment and Climate Change (DECC) once the variability of the groundwater quality is established.

Groundwater locations to be included in the initial groundwater quality monitoring suite shown in Table 12 include piezometers GCP25 to GCP34, GCP36, GCP38 as well as GW67291 and GW80968.


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Table 12 Groundwater Quality Monitoring Method and Frequency

Monitoring Suite Sampling Method Frequency

GCP25, 26, 28, 29, 30, 31 Pumped field meter readings Bi-monthly

GCP25, 26, 28, 29, 30, 31 Pumped sample for laboratory analysis Once yearly

GCP27, 32, 34, 36, 38 Pumped field meter readings Bi-monthly

GCP27, 32, 34, 36, 38 Pumped sample for laboratory analysis Once yearly

GW67291, GW80968 Pumped field meter readings Bi-monthly

GW67291, GW80968 Pumped sample for laboratory analysis Once yearly

10.1.3 Monitoring Procedures

Bores will be purged prior to sampling until continuous monitoring of the pH and salinity indicates they have stabilised. This usually involves removal of at least three bore volumes of groundwater.

Samples will be collected and placed in appropriately preserved containers and kept on ice in accordance with procedures identified in ANZECC (2000). Samples will be transported on ice under chain of custody documentation and arrive at the laboratory within appropriate holding times.

10.1.4 Private Bore and Well Groundwater Levels, Yield and Groundwater Quality

There are no known operational private DWE registered bores or wells within the Open Cut Project Area. However, one well (GW67291) and one monitoring bore (Richards Bore – GW80968) are located near to, although outside the Open Cut Project Area and are included in the groundwater level and groundwater quality monitoring suite as shown in Tables 11 and 12.

10.1.5 Mine Water Pumping

The volume of water pumped out of (or into) the Extended South Pit will be monitored to assess the actual volume of water stored within the pit as well as to assess the groundwater inflows and evaporation effects.

10.1.6 Rainfall

Rainfall would be monitored daily at the Integra meteorological station for the duration of Integra’s open cut and underground mining.

10.1.7 Ongoing Monitoring

All results would be reviewed and an updated monitoring and remediation program would be developed as required, in association with DWE, DECC and DPI-MR.


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10.1.8 Quality Assurance and Control

QA/QC would be attained by calibrating all measuring equipment, ensuring that sampling equipment is suitable for the intended purpose, using NATA registered laboratories for chemical analyses and ensuring that site inspections and reporting follow procedures outlined in the ANZECC 2000 Guidelines for Water Quality Monitoring and Reporting.

10.2 Contingency Measures Contingency procedures would be developed, as required, to manage any impacts identified by monitoring that may indicate unanticipated effects in the groundwater system’s response to mining.

Activation of contingency procedures would be linked to the assessment of monitoring results, including both water quality and aquifer pressure levels, as well as the rate of water level changes as outlined above.

Performance indicators would be identified and agreed to by DWE/ DPI-MR. In order to detect when a significant change has occurred in the groundwater environment, a statistical assessment would be undertaken prior to mining. The assessment would benchmark the pre-mining natural variation in groundwater quality and standing water levels, and from this trigger levels would be set for accepting accountability.

10.3 Impact Assessment Criteria

10.3.1 Groundwater Levels and Yield

As there are no private bores directly within the Open Cut Project Area, even though there is one well (GW67291) and one monitoring bore (GW80968) nearby, although outside, the Open Cut Project Area, the main focus will be on the Glennies / Station Creek alluvial groundwater levels and potential effects on stream flow within Glennies Creek.

Impact assessment criteria investigation trigger levels for the Quaternary alluvium will be initially set at an overall 2m sustained reduction in monitored groundwater levels in a piezometer over a 3 month period. In addition, the actual rate of change of water levels would be investigated to determine whether a change is solely mining induced or due to a range of other potential factors, such as variation in climate or altered rainfall / recharge relationship.

The monitoring, management and rehabilitation strategy used would comply with the relevant aquifer interference policies of the DWE.

It is proposed that water level monitoring data would be plotted and interpreted every twelve months, and if there is a significant increase in the rate of rise or fall in aquifer water levels, based on interpretation by a qualified hydrogeologist, then an assessment would be conducted to determine the cause of the change and to consider potential contingency measures that may be adopted.

If an outside party indicates that the Quaternary alluvium may have been adversely affected due to mining, an initial “desk top” assessment will be made as to whether the potential adverse effects are due to mining the proposed Pit or due to other effects. If the assessment indicates the effects may be due to mining, the alluvial piezometers will be re-monitored in the field and the cause of the adverse effect will be assessed.


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10.3.2 Groundwater Quality

Groundwater quality impact assessment criteria are sourced from the Australian Water Quality Guidelines for Fresh and Marine Waters (ANZECC, 2000) for Primary Industries (Irrigation Water) as shown in Table 13.

Table 13 Groundwater Quality Impact Assessment Criteria

Indicator Irrigation Criteria

pH <6.5 or >8.5 or >10% variation over 3 months compared to previous 12 months data

Conductivity >10% variation over 3 months compared to previous 12 months data

TDS >13,000mg/L or >10% variation compared to previous 12 months data

Na >460mg/L or >10% variation compared to previous 12 months data

K >10% variation compared to previous 12 months data

Ca >1000mg/L or >10% variation compared to previous 12 months data

Mg >10% variation compared to previous 12 months data

Cl >700mg/L or >10% variation compared to previous 12 months data

HC03 >10% variation compared to previous 12 months data

N03 >400mg/L or >10% variation compared to previous 12 months data

S04 >1000mg/ or >10% variation compared to previous 12 months data

A trigger to assess the cause and effects on groundwater quality would be implemented when there is a prolonged and extended non-conformance of the outlined criteria at a particular piezometer.

If the pH or conductivity is outside the designated criteria for at least six months, or alternatively, if it exceeds its previous range of results by greater than a 10% variation for at least 6 months, then the cause would be investigated, and a remediation strategy will be proposed, if warranted.

The criteria and triggers would be reviewed after the initial 12 month of data is interpreted and may be modified as appropriate, depending on the results.

If the impacts on the alluvial and Foybrook Formation groundwater system resulting from mining is demonstrated to be greater than anticipated, the company would:

• assess the significance of these impacts;

• investigate measures to minimise these impacts; and,

• describe what measures would be implemented to reduce, minimise, mitigate or remediate these impacts in the future to the satisfaction of the Director-General.


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10.4 Piezometer Licensing, Maintenance and Installation The Integra piezometer network will be protected from damage by cattle and from scrub fires by installing steel wellheads.

If required, the piezometers may be cleaned out by air sparging if they become clogged.

All new bores or piezometers would be installed by suitably licensed drillers after obtaining the relevant licence from DWE.

10.5 Rehabilitation Remedial action may be required if monitoring results indicate the agreed standards or performance indicators are not being achieved due to a failure in or the ineffectiveness of the Company’s management strategies.

If remedial action is required on private bore or well owners extraction facilities, potential measures could include:

• deepening the pump intake; or

• extending the total depth bore or well if an adequate equivalent pre – mining groundwater yield is not obtainable that is due directly to adverse mining effects.

However, due to the localised dewatering effect from the proposed Pit, it is not anticipated that groundwater system rehabilitation would be required.

10.6 Reporting An annual report will be prepared by a qualified hydrogeologist and will include:

• a basic statistical analysis (mean, range, variable, standard deviation) of the results for the parameters measured;

• an interpretation of water quality and standing water level changes supported with graphs or contour plots; and

• an interpretation and review of the results in relation to the impact assessment criteria.

Additionally, all relevant monitoring and management activities for each year would be reported in the mine’s Annual Environmental Management Report (AEMR).

At the completion of the open cut mining activity, an End of Mine report would be prepared that summarises all relevant monitoring to date. The report would outline any changes in the groundwater or surface systems within the study area.


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11. SUMMARY AND CONCLUSIONS Integra Coal Operations Pty Ltd (Integra) propose to extend their existing South Pit in a north-westerly direction. The extension to the South Pit is planned to be excavated to an approximate maximum depth of 250m below surface over a period of up to approximately nine years. Mining operations will include the extraction of a sequence of coal seams between the Lemington Seam and the Upper Hebden Seam.

The coal sequence is currently being mined by open cut methods by Integra in the adjoining South Pit, and the previously mined, and now backfilled North Pit. The backfilled North Pit is situated northeast of the proposed Mine Area, and is north of the South Pit.

Drilling, monitoring and field testing of 39 piezometers within the Integra mine leases indicate very low groundwater yields (<0.04L/sec) in the Foybrook Formation coal measures and low permeabilities (<0.2L/sec) in alluvium. Six open standpipe piezometers were installed up to 14m below surface in the Station Creek / Glennies Creek alluvium; six were installed up to 56.3m below surface in the coal measures and two multi-intake vibrating wire piezometers were installed down to the Hebden Seam at a maximum depth of 197m.

Field, laboratory and office assessments indicate that:

• the Foybrook Formation groundwater pH ranges from 6.5 to 8.5, with salinity between 1185µS/cm and 14,490µS/cm;

• the Station Creek / Glennies Creek alluvium groundwater pH ranges from 6.9 to 8.9, with salinity between 743µS/cm and 20,300µS/cm; and

• water accumulating in the final void is likely to exhibit a pH of approximately pH 8.5 and a salinity of 11,350µS/cm.

The proposed Pit will be excavated through the Permian Foybrook Formation overburden and interburden which contains a sequence of coal measures between the Lemington Seam and the Hebden Seam.

There will be no excavation through Quaternary alluvium or alluvial aquifers associated with Station Creek or Glennies Creek, as the edge of the proposed Pit will be located at least 150m east of the Station Creek valley fill alluvium, and will be approximately 350m east of Glennies Creek. The Station Creek and Glennies Creek alluvium consists of interbedded clay, sandy clay and gravelly units that range up to 14m below surface.

The seams and their associated overburden / interburden lie within a 6O west-north-westerly dipping sequence which is located to the east of the northerly trending Camberwell Anticline. Based on limited data, it is interpreted that one north-easterly trending fault zone with up to 5m displacement may be present to the west of the proposed Pit, whilst a second fault zone may intersect the western most edge of the proposed Pit.

The Mine Area is located within an essentially dry, ephemeral first and second order stream catchment which drains to the ephemeral channel of Station Creek, which in turn, flows into the perennial Glennies Creek. Glennies Creek then drains into the Hunter River approximately 5km south-west of the junction with Glennies Creek. The Mine Area is located within a low rainfall, high evaporation climatic regime.

The major creeks within and adjacent to the Open Cut Project Area were generally flowing during the study period, with Station Creek exhibiting a pH range of 6.0 to 9.5 and an electrical conductivity of 100 to 1900µS/cm, while Glennies Creek exhibited a range of pH


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6.2 to 9.7 and average salinities between 335 to 500µS/cm. The salinity in Glennies Creek has reached a maximum since 2002 of 950µS/cm.

All four of the Department of Water and Energy (DWE) registered wells within or near the Open Cut Project Area were installed in the alluvium of Glennies Creek, however only one is present and active (GW67291). Two registered bores are registered to be within or near the Open Cut Project Area, however only Richards Bore (GW 80968) is active and is being used as a monitoring piezometer by the DWE.

Short duration pump out tests and falling head tests assessed the Quaternary alluvium to have hydraulic conductivities ranging from 0.015m/day to approximately 0.61m/day, whilst the conductivities of the coal seams and interburden ranged from 8.64x10-7 to 4.8m/day.

Groundwater within the various seams to be extracted are generally confined, except where they are depressurised through extraction of the existing South Pit or they extend underneath the Station Creek and Glennies Creek alluvium.

Groundwater quality of the tested overburden, interburden and selected seams exceeds the ANZECC 2000 upland stream freshwater and 95% trigger level for freshwater species for pH, electrolytical conductivity, total nitrogen, total phosphorus, copper, and to a lesser degree, zinc and aluminium.

An assessment of acid rock drainage indicates that the waste rock is not potentially acid producing (WRM Water & Environment, 2008A).

A FEFLOW groundwater model was sequentially developed as the understanding of the regional hydrogeological system developed. The model represented the Open Cut Project Area with 11 layers, which incorporated the proposed coal extraction in the proposed Pit as well as the effect of adjacent open cut and underground mine workings.

Modelling indicates a regionally limited area of groundwater depressurisation due directly to development of the proposed Pit, however the drawdown in the Mine Area is combined with depressurisation from adjacent open cut and underground mines in the local area on both sides of Glennies Creek.

Modelling predicts that up to the Year 2018, when the proposed Pit is due to be completed, the regional drawdown within the Hebden Seam will extend underneath Glennies Creek. However drawdown in the alluvium is not modelled to extend into the creek channel. Depressurisation of the Quaternary alluvium of Glennies Creek within the vicinity of the proposed Pit is predicted to occur. However, no observable change in stream flow is predicted within Glennies Creek as a result of development of the development of the proposed Pit due to the minor change in alluvial groundwater outflow from the current 3.1ML/day to 4.2ML/day in 2018.

Current depressurisation around the existing South and Rix’s Creek Pits will substantially limit the rate of inflow to the proposed Pit and will partly mask the regional groundwater drawdown effects. Pit inflows of between the current 35ML/year to 117ML/year in 2018 are postulated by the modelling. However, the high evaporation rate would significantly reduce the volume of any water required to be pumped out of the Pit.

The model indicates that the nearest operating DWE registered bore (Richards Bore) may be affected by less than 1m of groundwater depressurisation due to mining the proposed Pit, however the bore could also currently be affected by mining within an adjacent operating mine. Similarly, the active well (GW67291) is modelled to be affected by less than 1m of drawdown.


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No adverse effects on stream flow or stream water quality are anticipated on Station Creek and its associated alluvial groundwater system.

Less than 2m of drawdown is anticipated within the connected alluvium of Glennies Creek due to the proposed open cut mining. The modelled drawdown is similar to the current variability in alluvial groundwater levels of up to 0.76m. As a result, the change in groundwater levels within the connected alluvium of Glennies Creek is not anticipated to adversely or observably affect stream flow or stream water quality in Glennies Creek .

Up to 7m of indirect drawdown is modelled in the disconnected, distal very low permeability, clay dominated alluvial sediments which are approximately 760m to the south / east of Glennies Creek in GCP26. The maximum drawdown will not occur until after 2024 when the Hebden Seam underground workings will be completed, and could occur up to 2031 when the Barrett Seam underground workings are proposed to be completed. The drawdown will not be due to the proposed open cut workings, as they are proposed to be completed in 2018.

No adverse effect on alluvial or coal measures groundwater quality is anticipated in the Open Cut Project Area from development of the “Full” or “Part” proposed Pit.

No adverse effects are anticipated on Groundwater Dependent Ecosystems in the Open Cut Project Area.

Water within the final void could range up to a salinity of approximately 11,350µS/cm, depending on the relative proportions of groundwater inflow, dirty water pumped into the void, surface water runoff and evaporation, with a pH of approximately 8.5 (WRM Water & Environment, 2008A).

Post-mining groundwater levels are modelled to partially recover following the cessation of mining, with the final relative level being dependent on the hydrogeological conditions prevalent at the time as well as the quantity of water pumped into the void from other storages across the Open Cut Project Area, as the final void is potentially to be used as an on-site dirty water storage and evaporation facility for the Integra Underground. However, the water management volumes are not detailed at this stage.


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12. COVERAGE OF DIRECTOR-GENERAL’S REQUIREMENTS This section outlines where the relevant groundwater related Director-General’s Requirements as outlined by Government agencies are discussed in this report.

AGENCY REQUIREMENT RELEVANT SECTIONS

Description of the existing environment 1.4, 2.1 to 2.7

Assessment of potential impacts of all stages of the project including any cumulative impacts that may arise from the combined operation of the project with any other existing, approved, or proposed mining operations in the region

6.5 to 6.7

7.1 to 7.4

8.1 to 8.2

9.0

Description of the measures that would be implemented to avoid , minimise, mitigate, rehabilitate/remediate, monitor and/or offset the potential impacts of the project, including detailed contingency plans for managing any potentially significant risks to the environment

10.1 to 10.6

Department of Planning – Mining and Extractive Industries Major Development Assessment

Detailed assessment of the potential impacts of the project on the quality, quantity and long term integrity of the surface water and groundwater resources in the Open Cut Project Area, paying particular attention to all significant watercourses and their associated tributaries.

6.5 to 6.7

7.1 to 7.4

8.1 to 8.2

9.0

13. REFERENCES AGE Pty Ltd, 2007 Groundwater Assessment of the Proposed Glennies Creek Open

Cut Coal Mine

Amira International, 2002, Free Draining Leach Column Test Procedure - ARD Test Handbook, Project P387A Prediction and Kinetic Control of Acid Mine Drainage.

ANZECC 2000 Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Vol 1 & 2

ANZECC 2000b Australian Guidelines for Water Quality Monitoring and Reporting

Aquaterra, 2008 Ashton Underground Mine LW / MW 5 – 9 Pikes Gully Seam Groundwater Impact Assessment Report

DEC, 2004 Approved Methods for the Sampling and Analysis of Water Pollutants in New South Wales

DEC, 2004 Contaminated Sites: Draft Guidelines for the Assessment and Management of Groundwater Contamination

DIPNR, 2005 Management of Stream / Aquifer Systems in Coal Mining Developments

DIPNR, 2003 Groundwater Monitoring Guidelines for Mines Within the Hunter Region


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DIPNR, 2005 Coal Mining Potential in the Upper Hunter Valley – Strategic Assessment Environmental Planning & Assessment Act 1979

DLWC, 1997 The NSW State Groundwater Policy Framework Document

DLWC, 1998 The NSW State Groundwater Quality Protection Policy

DLWC, 1998 Aquifer Risk Assessment Report

DLWC, 2002 NSW Groundwater Dependent Ecosystems Policy

DWE, 2003 Draft Water Sharing Plan, Hunter Unregulated and Alluvial Water Sources

DUAP, 2000 Coal Mines and Associated Infrastructure - EIS Guideline

Geoterra Pty Ltd, 2009 Barrett Seam and Hebden Seam Longwall / Bord and Pillar Groundwater Assessment

Integra Coal Operations 2008 Integra Coal Open Cut Water Management Plan

Hem, J.D. 1989 Study and Interpretation of the Chemical Characteristics of Natural Water, 3rd ed., USGS Water Supply Paper 2254

Mackie Environmental Research, 2000 Camberwell Coal Water Management Studies Final Report

Mackie Environmental Research, 2003 Mt Owen Operations EIS Hydrogeological Studies

NSW Govt Water Management Act 2000

P Dundon & Associates, 2006 Ashton Coal Mine Longwall Panels 1-4 Subsidence Management Plan, Groundwater Assessment

SCT Operations Pty Ltd, 2008 Packer Test Summary Hole DDH223, Integra Underground

SCT Operations Pty Ltd, 2008(A) Installation of 3 Vibrating Wire Piezometers in Borehole GCP35

SCT Operations Pty Ltd, 2008(A) Installation of 2 Vibrating Wire Piezometers in Borehole GCP37

Standards Australia, 1998 Australian / New Zealand Standard – Water Quality – Sampling. Part 11 Guidance on Sampling of Groundwaters. AS/NZS 5667.11:1998

Umwelt (Australia) Pty Ltd, 2007 Environmental Assessment For Modification of Glendell Mine Operations

WRM Water & Environment, 2008 Surface Water Assessment For Integra Proposed Pit Environmental Assessment

DISCLAIMER

This report was prepared in accordance with the scope of services set out in the contract between GeoTerra Pty Ltd (GeoTerra) and the client, or where no contract has been finalised, the proposal agreed to by the client. To the best of our knowledge the report presented herein accurately reflects the client's intentions when it was printed. However, the application of conditions of approval or impacts of unanticipated future events could modify the outcomes described in this document.


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The findings contained in this report are the result of discrete / specific methodologies used in accordance with normal practices and standards. To the best of our knowledge, they represent a reasonable interpretation of the general condition of the site / sites in question. Under no circumstances, however, can it be considered that these findings represent the actual state of the site / sites at all points. Should information become available regarding conditions at the site, GeoTerra reserve the right to review the report in the context of the additional information.

In preparing this report, GeoTerra has relied upon certain verbal information and documentation provided by the client and / or third parties. GeoTerra did not attempt to independently verify the accuracy or completeness of that information. To the extent that the conclusions and recommendations in this report are based in whole or in part on such information, they are contingent on its validity. GeoTerra assume no responsibility for any consequences arising from any information or condition that was concealed, withheld, misrepresented, or otherwise not fully disclosed or available to GeoTerra.

Interpretations and recommendations provided in this report are opinions provided for our Client’s sole use in accordance with the specified brief. As such they do not necessarily address all aspects of water, soil or rock conditions on the subject site. The responsibility of GeoTerra is solely to its client and it is not intended that this report be relied upon by any third party, who should make their own enquiries.

The advice herein relates only to this project and all results, conclusions and recommendations made should be reviewed by a competent and experienced person with experience in environmental and / or hydrological investigations before being used for any other purpose. The client should rely on its own knowledge and experience of local conditions in applying the interpretations contained herein.

To the extent permitted by law, GeoTerra, excludes all warranties and representations relating to the report. Nothing in these terms will exclude, restrict or modify any condition, warranty, right or remedy implied or imposed by any statute or regulation to the extent that it cannot be lawfully excluded, restricted or modified. If any condition or warranty is implied into this license under a statute or regulation and cannot be excluded, the liability of GeoTerra for a breach of the condition or warranty will be limited to the supply of the service again.

This report shall not be reproduced either wholly or in part without the prior written consent of GeoTerra.

APPENDIX A

PIEZOMETER DETAILS

Borehole: Client:

Project:

Location:

Job No:

North/East:

Logged by:

Drilled By:

Drill Method:

Drill Date:

Hole Size:

Ground RL:

Sheet: 1 of 1

GeoTerra77 Abergeldie Street

Dulwich Hill NSW 2203ph 02 9560 6583 fax 02 9560 6584

email [email protected]

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GCP25Integra Coal Operations

Barrett Hebden UG

T & K Dallas lease

GC12

6406766N 323066E

A Dawkins

Ground SurfaceLoamsilty dk brnSandfine grain, clayey, med brn to dk red brn at base

Sandfine to med grain

Sandmed-crs grain + gravel to 10mm

Gravelmed sandy with gravel to 30mm

Stick up 0.96m

SWL 7.52mbgl

hole collapsed to 9.15mbgl

ACE Drilling

Open hole hammer

Sept 07

5"

Borehole: Client:

Project:

Location:

Job No:

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Barret Hebden UG

Dallas lease

GC12

6406293N 323884E

A Dawkins

Ground SurfaceClaydk brn blkClaysilty dk brn blkClayorng gry brnGravelclayey, gravel to 20mm, red brn

Claysilty red brnGravelsilty clay, gravel to 10mmClaysilty orng brnSandfine grain, clayey, orng brn Siltstonev weath, orng brn

Stick up 0.73m

SWL 7.84mbgl


ACE Drilling

Open hole hammer

Sept 07

5"

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Project:

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GCP27Integra Coal

Western Extension

Western Extension

GC12

323197E 6406037N

C Coxhead

Ground SurfaceTopsoildk brnClayochre brn

Gravelpebble sized + sand

no returns

Conglomerateto 50mm poorly sorted

Stick up 1.10m

SWL 7.92mbgl

Hunter Drilling Services

open hole hammer

5/6/07

100mm

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GCP27Integra Coal

Western Extension

Western Extension

GC12

323197E 6406037N

C Coxhead

SandstoneCrs grain Lt gry

Conglomerateto 50mm poorly sorted

MudstonegrySandstoneFine grn , lt gry with mudstone laminaeMudstoneCarb at baseCoal (420 Sm)SandstoneFine grn, Lt gryMudstoneCoalSandstoneMudstone laminaeShaleCarbonaceous

Mudstone

Mudstone

Shale / ClaystoneEnd of Borehole

bent / grav backfill to 37.5mbgl

cement 258.2mbgl to 44mbgl

Hunter Drilling Services

open hole hammer

5/6/07

100mm

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Tree lot area

GC13

6405459N 322652E

A Dawkins

Ground SurfaceClaysilty dk brnClayfine sandy, med brn

Sandcrs sand in silty clay, brnSanda/a + fine gravel to 5mm med brnGravelclayey gravel 10mm to 20mm at base, orng brn

Sandcrs sand to fine gravel

Gravelgravel to 50mm in silty sand

Stick up 0.8m

SWL 6.50mbgl


ACE Drilling

Open hole hammer

Sept 07

5"

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Project:

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GC13

6405354N 323194E

A Dawkins

Ground SurfaceClaydk brnClaysilty, brn to orng br, fine sandy at base

Gravelfine sandy, gravel to 20mm

Gravelorng brn, gravel to 10mm

SandV coarse sand to fine gravelGravelgravel to 30mm

Siltstonegrey, fine sandy

stick up 0.9m

SWL 5.89mbgl


ACE Drilling

Open hole hammer

Sept 07

5"

Borehole: Client:

Project:

Location:

Job No:

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near core shed

GC13

6404652N 322440E

A Dawkins

Ground SurfaceClaysilty dk brn to orng brn at base

Gravelgravel to 30mm in silty clay matrix

Coalshaley coal, gry blk

Stick up 0.94m

SWL 5.03mbgl

hole collpased to 10.35mbgl

ACE Drilling

Open hole hammer

Sept 07

5"

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near core shed

GC13

6404425N 322931E

A Dawkins

Ground SurfaceClaysilty, dk brn orng to red brn orng at base

Gravelclayey, gravel to 30mm

Shaledk gry

Stick up 0.77m

SWL 7.56mbgl


ACE Drilling

Open hole hammer

Sept 07

5'

Borehole: Client:

Project:

Location:

Job No:

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101112131415161718192021222324252627282930

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GCP32Integra Coal Operations Pty Ltd

extended Pit

Tisdells Property

GC13

322493E 6404252N

A Dawkins

Ground SurfaceClaysilty, gry brnClaysilty, gravelly, orng brnClaysilty, yel, orng, brn

Claygravelly, red brn, to 50mm at base

Siltstonegrey

ConglomerategreySandstonefine grained gry

Sandstonefine grain, carbonaceous

Sandstonefine grain

swl 7

.01m

bgl

wet cuttings in basal graveldry basement

hole cased with steel to 14mbgl

Hunter Drilling

open hole hammer

August 2008

5"

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Project:

Location:

Job No:

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313233343536373839404142434445464748495051525354555657585960

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extended Pit

Tisdells Property

GC13

322493E 6404252N

A Dawkins

CoalSiltstonegrey

Sandstonefine grain, greySiltstoneto fine grain sandstone, grey

CoalSiltstoneto fine grain sandstone

CoalSiltstonecarbonaceousCoalSiltstonecarbonaceousCoal

End of Borehole

wet cuttingsdry basement

wet cuttingsdry basement

wet to EOH

Hunter Drilling

open hole hammer

August 2008

5"

Borehole: Client:

Project:

Location:

Job No:

North/East:

Logged by:

Drilled By:

Drill Method:

Drill Date:

Hole Size:

Ground RL:

Sheet: 1 of 1




Dep

th

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

Sym

bol Lithology

Wel

l Dat

a Remarks


extended Pit

Tisdells property

GC13

322586E 6404181N

A Dawkins

Ground SurfaceClaysilty red brn

Siltstonev weath yell brn

End of Borehole

hole backfilled on completion

no piezometer installed

Hunter Drilling

open hole hammer

August 2008

5"

Borehole: Client:

Project:

Location:

Job No:

North/East:

Logged by:

Drilled By:

Drill Method:

Drill Date:

Hole Size:

Ground RL:

Sheet: 1 of 2




Dep

th

0123456789

101112131415161718192021222324252627282930

Sym

bol Lithology

Wel

l Dat

a Remarks


extended Pit

Tisdells property

GC13

322800E 6403235N

A Dawkins

Ground SurfaceSilty Clayorng brn to yell brn

ConglomerateFine grain, wthrd, yell brn

ConglomerateFine grain, wthrd, dk orngConglomerateFine grain, wthrd, yell brn

SiltstoneWthrd, lt gry yell to lt gry

CoalSiltstonemed grey

CoalSiltstonelt grey

CoalSiltstonelt grey

losing air whilst drilling from 10-17mbgl (fractured)

Hunter Drilling

open hole hammer

August 2008

5"

Borehole: Client:

Project:

Location:

Job No:

North/East:

Logged by:

Drilled By:

Drill Method:

Drill Date:

Hole Size:

Ground RL:

Sheet: 2 of 2




Dep

th

313233343536373839404142434445464748495051525354555657585960

Sym

bol Lithology

Wel

l Dat

a Remarks


extended Pit

Tisdells property

GC13

322800E 6403235N

A Dawkins

Sandstonefine grain, lt grySiltstonelt greySandstoneFine grainSiltstonelt grey

Sandstoonefine grain lt grySiltstonelt grey

Siltstonecarbonaceous / coalySiltstonelt grey

Sandstonefine grain, lt gry

SandstonecarbonaceousCoalSiltstonecarbonaceous

End of Borehole

swl 4

4.25

mbg

l

moist returns

dry drilling

wet returns to EOH

0.225L/sec airlift at EOH

Hunter Drilling

open hole hammer

August 2008

5"

Redrilled as GCP35 (Page 1 of 10)


- 38m – airlift - dribble


- 44m – 0.06L/s airlift, pH 7.62, EC2170µS/cm




- 192m – 0.22L/s airlift, pH 8.08, EC 10310µS/cm


END OF HOLE – 197m

Borehole: Client:

Project:

Location:

Job No:

North/East:

Logged by:

Drilled By:

Drill Method:

Drill Date:

Hole Size:

Ground RL:

Sheet: 1 of 1




Dep

th

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

Sym

bol Lithology

Wel

l Dat

a Remarks

GCP36A Dawkins

extended Pit

near Tree lot

GC13

322916E 6405318N

A Dawkins

Ground SurfaceLoamsilty dk brnClaysilty med-orng-dk brn

Sandcoarse grain, brownSandv coarse, brnGravelsilty / clayey

SiltstoneWthrd, dk grey

End of Borehole

SW

L 7.

13 m

bgl

hole cased with steel to 13m

wet returns @15mbgl

Hunter Drilling

open hole hammer

August 2006

5"

Borehole: Client:

Project:

Location:

Job No:

North/East:

Logged by:

Drilled By:

Drill Method:

Drill Date:

Hole Size:

Ground RL:

Sheet: 1 of 5




Dep

th

0123456789

101112131415161718192021222324252627282930

Sym

bol Lithology

Wel

l Dat

a Remarks


West Extn Open Cut

West Extn Open Cut

GC13

324156 6405612

A Dawkins

Ground Surface

rubble

Comglomerate

Sandstonefine grn, gry wht brn

Coalmed grn, lt gryMudstoneCoalmed gryMudstoneMudstoneCoalMudstoneSiltstonemed, lt gryCoalMudstoneConglomerategrn gry white

Coal

first water make 2750 EC 9.10 pH

6" PVC cased to 24mbglEC 9080 pH 7.36

EC 5420 pH 8.39 airlift 0.001L/s

HDS

hammer

June 2008

4 1/2"

Borehole: Client:

Project:

Location:

Job No:

North/East:

Logged by:

Drilled By:

Drill Method:

Drill Date:

Hole Size:

Ground RL:

Sheet: 2 of 5




Dep

th

313233343536373839404142434445464748495051525354555657585960

Sym

bol Lithology

Wel

l Dat

a Remarks


West Extn Open Cut

West Extn Open Cut

GC13

324156 6405612

A Dawkins

Sandstonecrs grn, gry white

Mudstone

Conglomerate

Mudstone

Mudstone

CoalMudstone

CoalMudstoneSandstonemed crs grainSandstonefine grain

Sandstonemed grain

Sandstonefine grainSiltstoneSandstonemed crs grain



EC 1300 pH 9.09 airlidt 0.078L/s

HDS

hammer

June 2008

4 1/2"

Borehole: Client:

Project:

Location:

Job No:

North/East:

Logged by:

Drilled By:

Drill Method:

Drill Date:

Hole Size:

Ground RL:

Sheet: 3 of 5




Dep

th

616263646566676869707172737475767778798081828384858687888990

Sym

bol Lithology

Wel

l Dat

a Remarks


West Extn Open Cut

West Extn Open Cut

GC13

324156 6405612

A Dawkins

Sandstonecrs grain

Siltstone

Coal

Sandstonemed crs grain

Mudstone

Mudstone

Sandstonemed grainMudstonecarboniferous

MudstonecarboniferousCoalinterbanded with mudstoneSandstonemed grainSandstonefine grainCoalinterbanded mudstone

Vibrating wire piezometer intake



HDS

hammer

June 2008

4 1/2"

Borehole: Client:

Project:

Location:

Job No:

North/East:

Logged by:

Drilled By:

Drill Method:

Drill Date:

Hole Size:

Ground RL:

Sheet: 4 of 5




Dep

th

919293949596979899

100101102103104105106107108109110111112113114115116117118119120

Sym

bol Lithology

Wel

l Dat

a Remarks


West Extn Open Cut

West Extn Open Cut

GC13

324156 6405612

A Dawkins

MudstoneCoalSandstonemed grainSiltstoneCoalMudstoneSiltstoneCoal

MudstonecarboniferousCoal

Sandstonefine to med grain

Conglomerate

Sandstonecrs grain

Mudstone




HDS

hammer

June 2008

4 1/2"

Borehole: Client:

Project:

Location:

Job No:

North/East:

Logged by:

Drilled By:

Drill Method:

Drill Date:

Hole Size:

Ground RL:

Sheet: 5 of 5




Dep

th

121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150

Sym

bol Lithology

Wel

l Dat

a Remarks


West Extn Open Cut

West Extn Open Cut

GC13

324156 6405612

A Dawkins

Coal

Mudstonecarboniferous

End of Borehole

Vibrating wire piezometer intake

EC 5100 pH 8.40 airlift 0.099l/s

HDS

hammer

June 2008

4 1/2"

Borehole: Client:

Project:

Location:

Job No:

North/East:

Logged by:

Drilled By:

Drill Method:

Drill Date:

Hole Size:

Ground RL:

Sheet: 1 of 1




Dep

th

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

Sym

bol Lithology

Wel

l Dat

a Remarks


extended Pit

RHA pastoral land

GC13

323462E 6405628N

A Dawkins

Ground SurfaceClaysilty dk brnSiltstonewthrd orng gry

Siltstonefresh, dk gry to lt gry

Sandstonefine grain, lt gry

Siltstonelt gry

Coalinterlayered siltstoneSiltstonecarbonaceous

End of Borehole

SW

L 6.

74 m

bgl

17-19mbgl moist to wet returns

dry

23-24mbgl wet drilling

Hunter Drilling

open hole hammer

August 2008

5"

APPENDIX B

HYDRAULIC TESTS

Bore Data Units ValueInitial Water Level Reading m 1.1Water Level Reading at t=0 m 4.949Casing Radius (r) m 0.025Bore Radius (R) m 0.0575Slotted Length (L) m 7

Characteristic Time (To) min 8.7916Calculated Permeability m/day 0.04

DRAWN: APD

DATE: 28-Jul-08 RISING / FALLING HEAD TEST ANALYSISSCALE: NTS

INTEGRA COAL OPERATIONS PTY LTD

GCP25 (Glennies Creek Alluvium) FIGURE 1

GeoTerra

R2 = 0.9959

0.001

0.01

0.1

1

0 5 10 15 20 25Time (minutes)

s/s0

0500

100015002000250030003500400045005000

0.10 1.00 10.00 100.00

Time (minutes)D

raw

dow

n (m

m)

Project GC13 INTEGRA COAL OPERATIONS PTY LTD Drawn A Dawkins GCP26 GeoTerra Date 18.11.2009 Constant Rate Pumping Test Scale NTS

Constant Rate Pumping Test GCP26

Pumping Rate = 0.01 to 0.04L/sec Aquifer Thickness = 5.0m

Drawdown ∆S = 2.05 m

T = 2.3 Q/ 4∏ ∆S = 0.077 m2/day

Av K = 0.154 m/day


T = 2.3 Q/ 4∏ ∆S = 0.083 m2/day

Av K = 0.017 m/day

Bore Data Units ValueInitial Water Level Reading m 4.934Water Level Reading at t=0 m 2.015Casing Radius (r) m 0.025Bore Radius (R) m 0.0575Slotted Length (L) m 2


DRAWN: APD



GCP27 (Basement)

GeoTerra

R2 = 0.998

0.001

0.01

0.1

1

0 2 4 6 8 10 12 14 16 18Time (minutes)

s/s0

Bore Data Units ValueInitial Water Level Reading m 1.857Water Level Reading at t=0 m 3.71Casing Radius (r) m 0.025Bore Radius (R) m 0.0575Slotted Length (L) m 5.3


DRAWN: APD



GCP28 (Glennies Creek Alluvium) FIGURE 1

GeoTerra

R2 = 0.8525

0.001

0.01

0.1

1

0 1 2 3 4 5 6 7 8Time (minutes)

s/s0



DRAWN: APD



GCP29 (Glennies Creek Alluvium)

GeoTerra

R2 = 0.9843

0.001

0.01

0.1

1

0 0.5 1 1.5 2 2.5 3Time (minutes)

s/s0

0

500

1000

1500

2000

2500

3000

3500

0.10 1.00 10.00 100.00

Time (minutes)D

raw

dow

n (m

m)



Pumping Rate = 0.04L/sec Aquifer Thickness = 5.0m


T = 2.3 Q/ 4∏ ∆S = 0.303 m2/day

Av K = 0.06 m/day



DRAWN: APD



GCP31 (Glennies Creek Alluvium)

GeoTerra

R2 = 0.9788

0.001

0.01

0.1

1

0 2 4 6 8 10 12 14 16Time (minutes)

s/s0

0

1000

2000

3000

4000

5000

6000

7000

8000

0.10 1.00 10.00 100.00

Elapsed Time (minutes)D

raw

dow

n (m

)



Pumping Rate = 0.07 to 0.032L/sec Aquifer Thickness = 6m


T = 2.3 Q/ 4∏ ∆S = 0.179 m2/day

Av K = 0.03 m/day


T = 2.3 Q/ 4∏ ∆S = 0.22 m2/day

Av K = 0.036 m/day



DRAWN: APD



GCP34 (Coal Measures)

GeoTerra

R2 = 0.9615

0.001

0.01

0.1

1

0 1 2 3 4 5 6 7 8 9 10Time (minutes)

s/s0

0

100

200

300

400

500

600

0.10 1.00 10.00 100.00

Elapsed Time (Minutes)Dr

awdo

wn

(m)





T = 2.3 Q/ 4∏ ∆S = 7.213 m2/day

Av K = 4.80 m/day

010002000

3000400050006000

700080009000

0.1 1 10 100

Elapsed Time (minutes)D

raw

dow

n (m

)





T = 2.3 Q/ 4∏ ∆S = 0.131 m2/day

Av K = 0.018 m/day


T = 2.3 Q/ 4∏ ∆S = 0.129 m2/day

Av K = 0.018 m/day

APPENDIX C

GROUNDWATER LABORATORY ANALYSES

Laboratory Groundwater Chemistry

TDS Na Ca K Mg Cl F SO4 HCO3 Tot N Tot P Fe

Fe Filt

Filt Cu Filt Pb Filt Zn

Filt Ni

Filt Mn Filt Al

Filt Se Filt As

ALLUVIUM 15/09/2007 GCP28 340 71 37 1 17 140 0.21 19 130 <0.1 0.06 0.42 <0.01 <0.001 0.002 0.058 <0.01 0.11 0.04 <0.01 <0.01

15/09/2007 GCP29 3950 1080 120 6 165 1770 0.52 550 440 3.3 4 130.00 <0.01 <0.001 <0.001 0.009 <0.01 0.08 <0.01 <0.01 <0.01

15/09/2007 GCP30 4180 1120 165 7 200 2150 0.41 315 470 2.1 0.27 3.30 0.21 0.003 0.002 0.11 <0.01 0.57 0.04 <0.01 <0.01

15/09/2007 GCP31 12300 3550 285 12 590 6380 0.59 740 1090 <0.1 0.07 0.46 <0.01 0.001 0.001 0.058 <0.01 0.15 0.02 <0.01 <0.01

28/06/2008 GCP32 9520 2590 255 17 500 4930 0.2 1140 545 1.9 0.07 0.93 0.46 0.002 <0.001 0.13 <0.01 0.58 0.01 <0.01 <0.01

FOYBROOK FM

10/07/2007 GCP27 2950 310 820 220 3 99 0.46 445 <1 2.4 0.01 1.40 <0.01 0.001 0.004 0.016 <0.01 <0.01 <0.01 <0.01 <0.01

28/06/2008 GCP34 5570 1490 135 18 330 2470 0.69 1420 420 5.1 0.22 1.10 0.3 <0.001 <0.001 0.006 <0.01 0.3 0.04 <0.01 <0.01

31/05/2008 GCP35 (44-72) 2250 575 46 20 125 990 0.65 420 195 0.5 0.1 2.30 <0.01 <0.001 <0.001 <0.001 <0.01 0.08 0.12 <0.01 <0.01

31/05/2008 GCP35 (196) 5250 1580 79 13 200 2510 0.36 770 405 1.6 0.03 2.60 <0.01 <0.001 <0.001 <0.001 <0.01 0.2 0.07 <0.01 <0.01

28/06/2008 GCP36 670 175 37 2 36 225 0.2 310 29 <0.1 0.05 0.71 0.01 <0.001 <0.001 0.001 <0.01 0.08 <0.01 <0.01 <0.01

31/05/2008 GCP37 (24-30) 4650 1360 130 15 195 2050 0.62 940 375 0.6 0.06 3.00 <0.01 <0.001 <0.001 0.003 0.02 0.67 <0.01 <0.01 <0.01

31/05/2008 GCP37 (127.5) 2670 920 21 12 51 1150 0.8 480 205 0.7 0.34 8.30 <0.01 <0.001 <0.001 0.001 <0.01 0.08 <0.01 <0.01 <0.01

18/07/2008 GCP38 6600 2170 58 12 125 3460 0.23 325 710 0.6 <0.01 0.20 <0.01 0.004 <0.001 0.16 <0.01 0.12 <0.01 <0.01 <0.01

ANZECC

2000 0.25 0.02 0.0014 0.0034 0.008 0.011 1.9 0.055 0.011 0.024 (III) / 0.013(V)

NOTE: ANZECC default trigger values for risk of adverse effects from physical and chemical stressors in SE Aust. Upland Rivers

Shading indicates exceedance of criteria

APPENDIX D

FEFLOW GROUNDWATER MODEL

Date: 23 October 2008 Project No. 087636005 004 M To: Andrew Dawkins 1/4

MEMORANDUM

Model Setup Model physical boundaries were set up along the Camberwell Anticline to the west, the contact zone between Singleton Coal Measures and Wallaringa Formation to the east and the boundary between Singleton Coal Measures and Mulbring Siltstone to the south-east. All of those boundaries were set as no-flow boundaries due to the structural and hydrogeological characteristics (typified by very low hydraulic conductivities). Model south boundary was set along Hunter River and Wollombi Brook and was represented by the constant head boundary conditions. Model extent is presented in Figure 1.

Remaining rivers and creeks in the model were represented using 3rd kind of boundary conditions (head dependent boundaries) where flow in or out of the river depends on relative head difference between water level in the river and the surrounding geological strata.

The underground mining and consequent subsidence effects alter the hydraulic characteristics of the mined and overlying strata. The real distribution of the hydraulic conductivities within the underground mine subsidence areas is not known at this stage. The distribution applied in the model was based on the conceptual model of longwall mine subsidence and personal communication with Andrew Dawkins (Geoterra).

The hydraulic conductivities applied in the model to represent the subsidence effects of the longwall mining are summarised in Table 1 below. According to the provided timing of the respective mines development the subsidence zones were introduced gradually during the modelling process. Recharge in subsidence zones was applied at a rate of 2.5 x 10-5 m/d.

Table 1: Hydraulic conductivities adopted for the subsidence zones.

Zone Horizontal Hydraulic Conductivity (m/s)

Vertical Hydraulic Conductivity (m/s)

Mined Seams 1 x 10-4 1 x 10-4

Cavity zone between mined seam and ~30m above) 1 x 10-4 1 x 10-4

Zone Between Hebden Seam and Middle Liddell Seam (MLS) 1 x 10-4 1 x 10-4

Zone Between Barrett Seam and MLS 1 x 10-4 1 x 10-4

30m above MLS to 150m above MLS 1 x 10-5 1 x 10-6

150m above MLS to 28 mbgl 1 x 10-7 No change

Ground level to 28 mbgl (excluding alluvium) 1 x 10-6 1 x 10-4

Alluvium No change No change

TO Andrew Dawkins DATE 23 October 2008

CC

FROM Przemek Nalecki PROJECT No. 087636005 004 M

GLENNIES CREEK WESTERN EXTENSION, HEBDEN AND BARRETT UNDERGROUND GROUNDWATER MODELLING PRELIMINARY RESULTS


MEMORANDUM

Model Structure The model mesh consists of 140,855 elements and is shown in Figure 1. The mesh was refined along the alluvial deposits to more accurately represent any impact of mine dewatering and post-subsidence effects on alluvial groundwater systems.

Coal seams were combined into three major groups, represented by Middle Liddell (MLS), Barrett and Hebden Seams. East-West and North-South cross sections through the model are provided in Figures 2 and 3 respectively.

The physical layer structure of the model is presented below:

Layer 1 represents alluvial deposits along the main creeks in the Project Area, and weathered bedrock outside the alluvial channels. The layer has an uniform thickness of 8 m across the entire model

Layer 2 represents weathered bedrock, with a uniform thickness of 20 m across the model. The base of this layer corresponds to the base of surface fracturing due to the subsidence effects

Layer 3 represents overburden extending from the base of surface fracturing zone to MLS + 150 m

Layer 4 represents overburden extending from 150 m above the MLS to approximately 30 m above MLS

Layer 5 corresponds to the bedrock extending between 30 m above MLS

Layer 6 represents MLS, with a layer thickness set at 3 m

Layer 7 represents the bedrock between MLS and Barrett Seams

Layer 8 represents Barrett Seam of a nominal thickness of 3 m

Layer 9 represents the bedrock between Barrett and Hebden Seams

Layer 10 is the Hebden Seam with a nominal thickness of 3.1 m

Layer 11 corresponds to bedrock underlying the Hebden Seam. The layer has a nominal thickness of 150 m.

Model Parameters Rainfall recharge is expected to occur over the alluvial sediments of the major creeks and along the coal seam outcrops. The range of recharge is expected to be within a range of few to approximately 90 mm/y, based on available modelling reports for nearby mines in the project area. In the current model the applied net recharge varied between 4.5 and 8 mm/y, depending on the scenario modelled.

For the post-subsidence conditions, an increased recharge is also expected to occur over the area affected by surface cracking due to the subsidence. The recharge applied in the post-subsidence areas was set to 10mm/y.

General knowledge and packer test results in Bore DDH223 and Sites G&H, suggest a possibility of decrease of hydraulic conductivity of the modelled strata with depth. The applied in the model decrease of hydraulic conductivity with depth was also supplemented by the extrapolated relation between depth of the coal seam and its hydraulic conductivity, based on “Groundwater Assessment of the Proposed Glennies Creek Open Cut Coal Mine” prepared by Australasian Groundwater and Environmental Consultants Pty Ltd, and expressed as:


MEMORANDUM

k=0.0418*exp(-0.0159*z)

Where: 0.0418 – base hydraulic conductivity near surface (m/day), and

z – depth of the coal seam (m)

The hydraulic conductivities and storage parameters adopted in the model are summarised in Table 2 below.

Table 2: Hydraulic Conductivity, Storage and Recharge Parameters Adopted for Modelling

Model Zone Horizontal Hydraulic

Conductivity (m/s)

Vertical Hydraulic Conductivity (m/s)

Specific Yield (-) / Specific Storage

(1/m)

Recharge (m/d)

Alluvium C1 - 9.2 x 10-7

C2 – 5.8 x 10-5 C1 - 4.6 x 10-7

C2 - 2.9 x 10-5 0.20 / - C1 – 4.5mm/y^ C2 – 8.0mm/y^

Weathered Sandstone 1.0 x 10-8 1.0 x 10-9 0.005 / 5 x 10-6 -

Fresh Sandstone / Shale - shallow 1.0 x 10-9 1.0 x 10-10 0.005 / 5 x 10-6 -

Fresh Sandstone / Shale - deep 1.0 x 10-10 1.0 x 10-11 0.005 / 5 x 10-6 -

Middle Liddell Seam - shallow 1.80 x 10-7 1.80 x 10-8 0.03 / 5 x 10-6 2.2 x 10-5*

Middle Liddell Seam - deep 4.1 x 10-9 4.1 x 10-10 0.03 / 5 x 10-6 -

Barrett Seam - shallow 9.0 x 10-8 9.0 x 10-9 0.03 / 5 x 10-6 2.2 x 10-5*

Barrett Seam - deep 2.8 x 10-9 2.8 x 10-10 0.03 / 5 x 10-6 -

Hebden Seam - shallow 4.0 x 10-9 4.0 x 10-10 0.03 / 5 x 10-6 2.2 x 10-5*

Hebden Seam - deep 1.9 x 10-9 1.9 x 10-10 0.03 / 5 x 10-6 -

Note: * Applied at surface only, ^ C1-Case 1 and C2 – Case 2

Two cases were modelled. The only difference between the cases was hydraulic conductivity value applied in the alluvium. In modelled Case 1 the hydraulic conductivity was set to 9.2 x 10-7 m/s as indicated by falling head tests carried out by Geoterra in the vicinity of the proposed mining operations, in Case 2 the hydraulic conductivity of the alluvium was set to 5.8 x 10-5 as used by other consultants in their modelling investigations for nearby mining operations.

Hydraulic conductivities used to model operational and post-closure conditions in the Full Pit Extension are presented in Table 3.

Table 3: Parameters adopted for South Pit/South Pit Extension Parameter Hydraulic Conductivity

(m/s) Specific Yield (-) Specific Storage (1/m)

Operational 1 x 10-3 No change 5 x 10-6 Post Backfill / Pit Lake 1 x 10-4 / 1 x 10-3 0.2 / 0.99 5 x 10-6


MEMORANDUM

MODELLING RESULTS Model generated inflow rates into the simulated mines are presented in Table 4.

Table 4: Model generated inflow rates Time

2008 2014 2018 2024 2031 2041 Mine Inflow Rates in m3/d

Glennies Creek Underground 400 700 - - - -

Full Pit - 200 320 - - - South Pit 100 - - - - - Hebden Underground - 320 560 1258 - - Barrett Underground - - - 52 708 -

It should be noted that due to the character of the fractured rock mass, the inflow rates will be primarily regulated by the fracture systems surrounding the underground/open cut voids. This will result in higher inflow rates when extensive fracture systems are cut through, and declining seepage rates when mining through rock with minor fracturing (tight rock).

Modelled initial (current) groundwater head distribution and drawdown contours showing a difference between initial and predicted groundwater head in model Layers 1 to 3, the Middle Liddell Coal Seam and the Hebden Coal Seam are presented in Figures 4 to 33.

Hydrographs for observation bores located in alluvium (Figure 34) are presented in Figures 35 and 36. Discharge rates from Glennies Creek into the alluvium in the vicinity of the underground operations and the Full Pit Extension area are presented in Figures 37 and 38.

Attachments:

087636005 004 Figures. PDF

J:\Hyd\2008\087636005-GlenniesCreek\Correspondence Out\087636005 004 M.doc

Information contained on this drawing is the copyright of Golder Associates Pty Ltd. Unauthorised use or reproduction of this plan either wholly or in part without written permission infringes copyright . © Golder Associates Pty Ltd.

DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT

Integra Coal Operations Pty Ltd

NVM OCT 08

NOT TO SCALE

Glennies Creek Western Extension

J:\Hyd\2008\087636005-GlenniesCreek\Correspondence Out\087636005 Figs.ppt

A3REV No

1 A

OCT 08PN

087636005

Model Mesh and Extent

312000 314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

2 A

OCT 08PN

087636005

A

A

A’

A’

East-West Cross Section of Model


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

3 A

OCT 08PN

087636005

B

B

B’

B’

North-South Cross Section of Model


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

4 A

OCT 08PN

087636005

Initial Water Level (Layer 1)

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek



Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

5 A

OCT 08PN

087636005

Initial Water Level (Layer 2)

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek



Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

6 A

OCT 08PN

087636005

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek

Initial Water Level (Middle Liddell Seam)


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

7 A

OCT 08PN

087636005

Initial Water Level (Barrett Seam)

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

8 A

OCT 08PN

087636005

Initial Water Level (Hebden Seam)

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek



Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

9 A

OCT 08PN

087636005

Modelled Drawdown Year 2014 (Layer 1)

Drawdown in metres

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek



Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

10 A

OCT 08PN

087636005


Drawdown in metres

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek



Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

11 A

OCT 08PN

087636005

Modelled Drawdown Year 2014 (Middle Liddell Seam)

Drawdown in metres

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek



Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

12 A

OCT 08PN

087636005

Modelled Drawdown Year 2014 (Hebden Seam)

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek

Drawdown in metres


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

13 A

OCT 08PN

087636005


Drawdown in metres

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek



Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

14 A

OCT 08PN

087636005


Drawdown in metres

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek



Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

15 A

OCT 08PN

087636005


Drawdown in metres



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek



Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

16 A

OCT 08PN

087636005


314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek

Drawdown in metres


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

17 A

OCT 08PN

087636005


Drawdown in metres



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & Pillar1

Bord & Pillar1

Bord & Pillar4

Bord & Pillar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

18 A

OCT 08PN

087636005



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & Pillar1

Bord & Pillar1

Bord & Pillar4

Bord & Pillar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


Drawdown in metres


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

19 A

OCT 08PN

087636005



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & Pillar1

Bord & Pillar1

Bord & Pillar4

Bord & Pillar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


Drawdown in metres


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

20 A

OCT 08PN

087636005

Modelled Drawdown Year 2024 (Barrett Seam)

Drawdown in metres



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & Pil lar1

Bord & Pi llar1

Bord & Pil lar4

Bord & Pil lar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

21 A

OCT 08PN

087636005


Drawdown in metres



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & Pil lar1

B ord & Pi ll ar1

Bord & Pil lar4

Bord & P ill ar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

22 A

OCT 08PN

087636005


Drawdown in metres



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & Pil lar1

Bord & Pil lar1

Bord & Pi ll ar4

Bord & Pil lar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

23 A

OCT 08PN

087636005



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & Pillar1

Bord & Pillar1

Bord & Pillar4

Bord & Pillar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


Drawdown in metres


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

24 A

OCT 08PN

087636005



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & Pillar1

Bord & Pillar1

Bord & Pillar4

Bord & Pillar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


Drawdown in metres


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

25 A

OCT 08PN

087636005


Drawdown in metres



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & Pil lar1

Bord & Pi llar1

Bord & Pil lar4

Bord & Pil lar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

26 A

OCT 08PN

087636005


Drawdown in metres



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & Pil lar1

B ord & Pi ll ar1

Bord & Pil lar4

Bord & P ill ar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

27 A

OCT 08PN

087636005


Drawdown in metres



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & Pi ll ar1

Bord & P ill ar1

Bord & Pil lar4

B ord & Pi llar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

28 A

OCT 08PN

087636005



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & Pillar1

Bord & Pillar1

Bord & Pillar4

Bord & Pillar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


Drawdown in metres


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

29 A

OCT 08PN

087636005



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & Pillar1

Bord & Pillar1

Bord & Pillar4

Bord & Pillar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


Drawdown in metres


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

30 A

OCT 08PN

087636005


Drawdown in metres



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & Pil lar1

Bord & Pi llar1

Bord & Pil lar4

Bord & Pil lar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

31 A

OCT 08PN

087636005


Drawdown in metres



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek




Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

Bord & P ill ar1

Bord & Pil lar1

Bord & Pill ar4

Bord & Pi llar5

314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

32 A

OCT 08PN

087636005

Location of Alluvium Monitoring Bores



Mt Owen Pit

North Open Cut

Existing South Pit




Ashton Underground

Ashton Pit

Glendell Pit


Eastern Rail Pit


Portal Sump

RixsCreek

Barret Seam UnderGround



Mt Owen Pit

North Open Cut

Existing South Pit




Eastern Rail Pit

Portal Sump

312000 314000 316000 318000 320000 322000 324000 326000 328000 330000 332000

6396000

6398000

6400000

6402000

6404000

6406000

6408000

6410000

6412000

6414000

6416000

GC10

GC9GC11

GC12

GC17

GC19GC20

GC21 GC22GC23

GC25GC26

GC28GC29

GC30

GC31

GC3S

GC4S


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

33 A

OCT 08PN

087636005

Model Generated Drawdown in Observation Bores in Alluvium (Case 1)

-8

-7

-6

-5

-4

-3

-2

-1

0

2005 2010 2015 2020 2025 2030 2035 2040 2045

GC11GC12GC17GC9GC10GC19GC20GC21GC22GC23GC25GC26GC28GC29GC30GC31GC3SGC4S


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

34 A

OCT 08PN

087636005

Model Generated Drawdown in Observation Bores in Alluvium (Case 2)

-3

-2.5

-2

-1.5

-1

-0.5

0

2005 2010 2015 2020 2025 2030 2035 2040 2045

Time (Years)

Draw

dow

n (m

)

GC11GC12GC17GC9GC10GC19GC20GC21GC22GC23GC25GC26GC28GC29GC30GC31GC3SGC4S


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

35 A

OCT 08PN

087636005

Model Generated Discharge from Glennies Creek (Case 1)

2008 2013 2018 2023 2028 2033 2038Time (y)

20

40

60

80

Cre

ek D

isch

arge

(m3 /d

)

Underground Mining

2008 2013 2018 2023 2028 2033 2038Time (y)

8

12

16

20

Cre

ek D

isch

arge

(m3 /d

)

Western Extension


DATE

DATE

FIGURE No

CLIENT

DRAWN

CHECKED

SCALE

TITLE

PROJECT No

PROJECT


NVM OCT 08

NOT TO SCALE



A3REV No

36 A

OCT 08PN

087636005

Model Generated Discharge from Glennies Creek (Case 2)

2008 2013 2018 2023 2028 2033 2038Time (y)

200

220

240

260

280

Cre

ek D

isch

arge

(m3 /d

)

Underground Mining

2008 2013 2018 2023 2028 2033 2038Time (y)

48

49

50

51

52

53

54

Cre

ek D

isch

arge

(m3 /d

)

Western Extension

appendix c - bloomcoll.com.au complex...figure 10 glennies creek alluvium cross sections and...

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