chapter 12 – water values and quality - metro mining · 2018-08-09 · skardon river bauxite...

CHAPTER 12 – WATER VALUES AND QUALITY

GULF ALUMINA LTD – SKARDON RIVER BAUXITE PROJECT

Skardon River Bauxite Project Chapter 12 – Water Values and Quality

Page 12-i

TABLE OF CONTENTS

12.1 Introduction ..................................................................................................... 12-1 12.2 Environmental Objectives and Performance Outcomes ..................................... 12-1 12.2.1 Environmental Objectives ........................................................................................ 12-1 12.2.2 Performance Outcomes ........................................................................................... 12-1 12.3 Legislative and Policy Context ........................................................................... 12-2 12.3.1 Environmental Protection Act 1994 ......................................................................... 12-2 12.3.2 Environmental Protection (Water) Policy (2009) ..................................................... 12-2 12.3.3 Water Quality Guidelines ......................................................................................... 12-2 12.3.4 Model Mining Conditions ......................................................................................... 12-3 12.3.5 Environmental Authority .......................................................................................... 12-3 12.4 Environmental Values ...................................................................................... 12-4 12.4.1 Catchments and Watercourses ................................................................................ 12-4 12.4.2 Wetlands .................................................................................................................. 12-7 12.5 Water Quality Objectives ................................................................................ 12-14 12.5.1 Environmental Values from EPP Water.................................................................. 12-14 12.5.2 Default Water Quality Objectives .......................................................................... 12-14 12.5.3 Proposed Water Quality Objectives ....................................................................... 12-21 12.5.3.1 Surface Water ......................................................................................................... 12-21 12.5.3.2 Groundwater .......................................................................................................... 12-24 12.6 Surface Water Monitoring .............................................................................. 12-28 12.6.1 Surface Water Monitoring Locations ..................................................................... 12-28 12.6.2 Surface Water Level Data ....................................................................................... 12-31 12.6.3 Surface Water Quality ............................................................................................ 12-32 12.6.3.1 Physical Parameters ............................................................................................... 12-32 12.6.3.2 Metals ..................................................................................................................... 12-33 12.6.3.3 Nutrients ................................................................................................................ 12-34 12.7 Groundwater Monitoring ............................................................................... 12-34 12.7.1 Groundwater Monitoring Locations and Parameters ............................................ 12-34 12.7.2 Groundwater Levels ............................................................................................... 12-41 12.7.3 Groundwater Quality ............................................................................................. 12-42 12.7.3.1 Physical Parameters ............................................................................................... 12-43 12.7.3.2 Metals ..................................................................................................................... 12-44 12.7.3.3 Nutrients ................................................................................................................ 12-47 12.8 Potential Impacts, Emissions and Releases ...................................................... 12-47 12.9 Mitigation and Management Measures .......................................................... 12-48 12.9.1 Mine Pits ................................................................................................................. 12-48 12.9.1.1 Mine Site Sediment Management ......................................................................... 12-49 12.9.1.2 Mine Site Sediment Pond Management ................................................................ 12-50 12.9.2 Port Infrastructure Area ......................................................................................... 12-50 12.9.2.1 Design and Management ....................................................................................... 12-50 12.9.2.2 Release Monitoring ................................................................................................ 12-53 12.9.3 Effluent Irrigation Area ........................................................................................... 12-53 12.9.4 Erosion and Sediment Control ............................................................................... 12-53 12.9.4.1 Erosion and Sediment Control Plan ....................................................................... 12-53 12.9.4.2 Permanent Haul Roads ........................................................................................... 12-55 12.9.5 Namaleta Creek Crossing ....................................................................................... 12-55 12.9.5.1 Location .................................................................................................................. 12-55 12.9.5.2 Existing Crossing ..................................................................................................... 12-55


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12.9.5.3 Crossing Design ...................................................................................................... 12-55 12.9.5.4 Crossing Drainage ................................................................................................... 12-58 12.9.5.5 Crossing Construction and Rehabilitation .............................................................. 12-59 12.9.6 Crossings of other Drainage Features .................................................................... 12-59 12.10 Surface Water and Groundwater Monitoring Plan ........................................... 12-62 12.10.1 Surface Water Monitoring Locations ..................................................................... 12-63 12.10.2 Surface Water Monitoring Frequency and Parameters ......................................... 12-69 12.10.3 Receiving Environment Monitoring Programme ................................................... 12-69 12.10.4 Management Measures in Response to Monitoring ............................................. 12-70 12.10.4.1 Water Quality ......................................................................................................... 12-70 12.10.4.2 Wetland Water Levels ............................................................................................ 12-70 12.10.5 Groundwater Monitoring ....................................................................................... 12-71 12.10.6 Saline Water Ingress ............................................................................................... 12-72 12.10.7 Targeted Monitoring Bores .................................................................................... 12-77 12.10.8 Management Measures in Response to Monitoring ............................................. 12-77 12.10.8.1 Groundwater Quality – Mining Areas .................................................................... 12-77 12.10.8.2 Groundwater Quality – Saline Water Intrusion ..................................................... 12-78 12.10.8.3 Groundwater Quality – Port Area and Treated Effluent Irrigation Area ................ 12-78 12.10.8.4 Groundwater Levels ............................................................................................... 12-79 12.11 Risk Assessment ............................................................................................. 12-80 12.12 Cumulative Impacts ........................................................................................ 12-80 12.13 Conclusion ..................................................................................................... 12-82

Tables

Table 12-1 Water Quality Trigger Values – AWQG, Model Mining Conditions and Existing EA .............................................................................................................. 12-17

Table 12-2 Nominated Water Quality Objectives – Namaleta Creek and Wetlands ............... 12-22 Table 12-3 Surface Water Monitoring Data ............................................................................. 12-28 Table 12-4 Surface Water Levels .............................................................................................. 12-31 Table 12-5 Surface Water Physical Parameter Summary Results – Namaleta Creek .............. 12-32 Table 12-6 Surface Water Physical Parameter Summary Results – Wetlands ......................... 12-32 Table 12-7 Surface Water Physical Parameter Summary Results – Kaolin Water

Storages .................................................................................................................. 12-32 Table 12-8 Surface Water Dissolved Metals Summary Results –Namaleta Creek ................... 12-33 Table 12-9 Surface Water Dissolved Metals Summary Results – Wetlands ............................ 12-33 Table 12-10 Surface Water Dissolved Metals Summary Results – Kaolin Water Storages ........ 12-33 Table 12-11 Surface Water Nutrient Summary Results – Namaleta Creek ............................... 12-34 Table 12-12 Surface Water Nutrient Summary Results - Wetlands ........................................... 12-34 Table 12-13 Surface Water Nutrient Summary Results - Kaolin Water Storages ...................... 12-34 Table 12-14 Groundwater Monitoring Data .............................................................................. 12-37 Table 12-15 Groundwater Level Data ........................................................................................ 12-41 Table 12-16 Groundwater Physical Parameter Summary Results – All Bores ........................... 12-43 Table 12-17 Groundwater Physical Parameter Summary Results – Bulimba Formation

(Namaleta Creek) Aquifer....................................................................................... 12-43 Table 12-18 Groundwater Physical Parameer Summary Results – Bulimba Formation

Aquifer .................................................................................................................... 12-44 Table 12-19 Groundwater Physical Parameter Summary Results – Rolling Downs

Siltstone Aquifer ..................................................................................................... 12-44 Table 12-20 Groundwater Dissolved Metals Summary Results – All Bores ............................... 12-45


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Table 12-21 Groundwater Dissolved Metals Summary Results – Bulimba Formation (Namaleta Creek) Aquifer....................................................................................... 12-45

Table 12-22 Groundwater Dissolved Metals Summary Results – Bulimba Formation Aquifer .................................................................................................................... 12-46

Table 12-23 Groundwater Dissolved Metals Summary Results – Rolling Downs Siltstone Aquifer .................................................................................................................... 12-46

Table 12-24 Groundwater Nutrient Summary Results – All Bores............................................. 12-47 Table 12-25 Groundwater Nutrient Summary Results – Bulimba Formation (Namaleta

Creek) Aquifer ........................................................................................................ 12-47 Table 12-26 Groundwater Nutrient Summary Results – Bulimba Formation Aquifer ............... 12-47 Table 12-27 Groundwater Nutrient Summary Results – Rolling Downs Siltstone Aquifer ........ 12-47 Table 12-28 Catchments Areas, Sediment Runoff and Pond/Dam Sizing .................................. 12-50 Table 12-29 Existing and Proposed Surface Water Monitoring Network .................................. 12-65 Table 12-30 Groundwater Monitoring Network ........................................................................ 12-73 Table 12-31 Risk Assessment and Management Measures for Impacts to Water Quality ........ 12-80

Figures

Figure 12-1 Regional Catchments ................................................................................................ 12-5 Figure 12-2 Local Catchments ..................................................................................................... 12-6 Figure 12-3 Wetlands – Queensland WetlandInfo Mapping ....................................................... 12-9 Figure 12-4 Wetlands of Namaleta Creek Catchment - Queensland WetlandInfo

Mapping ................................................................................................................. 12-10 Figure 12-5 Referrable Wetlands – Wetland Management Areas ............................................ 12-11 Figure 12-6 Vegetation Management Act Wetlands and Watercourses .................................. 12-12 Figure 12-7 Directory of Important Wetlands ........................................................................... 12-13 Figure 12-8 Surface Water Monitoring Locations ..................................................................... 12-30 Figure 12-9 Site S8 Surface Water Level and Rainfall ................................................................ 12-31 Figure 12-10 Groundwater Monitoring Locations ....................................................................... 12-40 Figure 12-11 Standing Groundwater Level – Bore C1 ................................................................. 12-42 Figure 12-12 Standing Groundwater Level – Bore G3 ................................................................. 12-42 Figure 12-13 Port Area Sediment Ponds and Drainage ............................................................... 12-52 Figure 12-14 Namaleta Creek Crossing Location ......................................................................... 12-57 Figure 12-15 Namaleta Creek Crossing – Downstream View ...................................................... 12-58 Figure 12-16 Haul Road Crossing of Drainage Feature ................................................................ 12-61 Figure 12-17 Existing and Proposed Surface Water Monitoring Locations ................................. 12-64 Figure 12-18 Existing and Proposed Monitoring Bores ............................................................... 12-76 Figure 12-19 Conceptual Mine Plan – Bauxite Hills Project ........................................................ 12-81


Page 12-1

12. WATER VALUES AND QUALITY

12.1 Introduction

This chapter describes the surface water environment, including catchments and wetlands, within and surrounding the Project area, describes surface water quality and groundwater quality from field samples, establishes environmental values and water quality objectives for waters in the Project area, describes potential impacts to water quality, proposes measures to mitigate impacts and provides a risk assessment for residual impacts.

Information in this chapter is primarily based on the information provided in Appendix 4.

Appendix 15 provides the Surface Water and Groundwater Monitoring Plan. Key elements of this plan are described in this chapter.

Chapter 14 describes flood modelling and potential impacts from flooding from watercourses on the Project.

Chapter 13 describes the surface water and groundwater hydrological and hydrogeological regimes of the Project, potential impacts and mitigation measures.

12.2 Environmental Objectives and Performance Outcomes

The environmental objectives and performance outcomes below are based on Schedule 5, Table 2 of the Environmental Protection Regulations 2008 (EP Regulation). The mitigation and management measures presented in this chapter are designed to achieve these environmental objectives and performance outcomes. The environmental management plan (EM Plan) presented in Appendix 13 provides a consolidated description of these mitigation and management measures.

12.2.1 Environmental Objectives

The activity will be operated in a way that protects environmental values of waters.

The activity will be operated in a way that protects the environmental values of wetlands.

The activity will be operated in a way that protects the environmental values of groundwater and

any associated surface ecological systems.

The choice of the site, at which the activity is to be carried out, minimises serious environmental

harm on areas of high conservation value and special significance and sensitive land uses at adjacent

places.

12.2.2 Performance Outcomes

Contingency measures will prevent or minimise adverse effects on the environment due to

unplanned releases or discharges of contaminants to water.

The activity will be managed so that stormwater contaminated by the activity that may cause an

adverse effect on an environmental value will not leave the site without prior treatment.

Any discharge to water or a watercourse or wetland will be managed so that there will be no

adverse effects due to the altering of existing flow regimes for water or a watercourse or wetland.

The activity will be managed so that adverse effects on environmental values are prevented or

minimised.


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The activity will be managed in a way that prevents or minimises adverse effects on wetlands.

The activity will be managed to prevent or minimise adverse effects on groundwater or any

associated surface ecological systems.

Areas of high conservation value and special significance likely to be affected by the proposal are

identified and evaluated and any adverse effects on the areas are minimised, including any edge

effects on the areas.

Critical design requirements will prevent emissions having an irreversible or widespread impact on

adjacent areas.

12.3 Legislative and Policy Context

12.3.1 Environmental Protection Act 1994

The Environmental Protection Act 1994 (EP Act) provides for environmental protection policies that establish the environmental values (EVs) which are to be protected, that include quality standards that are relevant to the water environment. The EVs of waterways in Queensland (including groundwater) are protected under the EP Act and the subordinate Environmental Protection (Water) Policy 2009 (EPP Water).

12.3.2 Environmental Protection (Water) Policy (2009)

The EPP Water establishes a process for identifying environmental values to be protected and states standards for water quality in support of those values. This policy is supported by the Queensland Water Quality Guidelines 2009 (QWQG).

The EPP Water provides a framework for the following:

Identifying environmental values and management goals for Queensland waters.

Stating water quality guidelines and objectives to enhance the environmental values.

Providing a framework for making consistent, equitable and informed decisions about Queensland

waters.

Monitoring and reporting on the condition of Queensland waters.

The EPP Water has been established to protect Queensland waters while allowing for ecologically sustainable development. The purpose of the policy is to identify EVs for aquatic ecosystems and for human uses; and determine water quality guidelines and water quality objectives to protect EVs. Aquatic ecosystems in both surface and groundwater habitats have EVs that require certain levels of protection under the EPP Water.

EVs and water quality objectives have been established for many waterways in Queensland under Schedule 1 of the EPP Water. Environmental values and associated water quality objectives have not been established for the rivers in Cape York potentially impacted by the Project.

The EPP Water defines an indicator for an EV as a property that can be measured or decided in a quantitative way. Water quality objectives are numerical concentrations or statements for indicators that protect a stated environmental value and are generally developed based on the review of the available site-specific information relevant to each environmental value.

12.3.3 Water Quality Guidelines

The Australian and New Zealand Environment and Conservation Council (ANZECC) has developed the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC & ARMCANZ 2000)


Page 12-3

(hereafter referred to as the Australian Water Quality Guidelines (AWQG)). The AWQG are numerical concentration limits or descriptive statements that can be applied to a range of ecosystem types and water uses, such as recreational and stock water. Water quality guidelines give recommended values for indicators and are designed to ensure that EVs of waters are protected. The need to develop guidelines for specific regions, water types and local flora and fauna is one of the main reasons why the QWQGs were developed.

Section 4 of the QWQG recommends the use of local water quality objectives developed for appropriate indicators / parameters using monitoring data from local reference sites. The QWQG stipulates a minimum set of eight independent surveys over 12 months from each reference site to establish ‘interim local water quality objectives’, and a further 10 independent surveys over the next 12 month to establish ‘local water quality objectives’ where there are two or less reference sites. Where there are three or more reference sites, a further four independent surveys over the next 12 months are needed to establish local water quality objectives. A reference site is defined as ‘a site whose condition is considered to be a suitable baseline or benchmark for assessment and management of sites in similar water bodies’. The water quality objective is then determined using the 20th and 80th percentile, as appropriate, for each parameter from these independent survey data.

12.3.4 Model Mining Conditions

The model mining conditions are a set of model conditions to form general environmental protection commitments given for mining activities, and environmental authority conditions for resource activities imposed by the administering authority under the EP Act. These model conditions have been used as a guide for developing environmental protection commitments relating to water management and for appropriate conditions for an environmental authority for the Project.

12.3.5 Environmental Authority

Gulf has an existing environmental authority (EA) issued for the kaolin mine which has ceased operations. This EA governs the ongoing rehabilitation, decommissioning and management of the kaolin mine, formerly a Level 1 mining project on the Mining Leases ML 6025, ML 40069 and ML 40082.

Gulf recognises that the existing EA (including conditions related to water management) will be amended as an outcome of the EIS process. The current EA addresses the following areas relevant to water management for the kaolin mine:

Requirement for monitoring receiving waters affected by the release of process water or

stormwater contaminated by kaolin mining activities.

Prohibition of waste deposition and the release of Acid Sulphate Soils (ASS) to any waters.

Monitoring locations and frequencies (receiving waters, end of pipe discharge, groundwater

affected by kaolin mining activities).

Contaminant release limits for end of pipe discharges, sewage effluent for irrigation, and

groundwater.

Contaminant trigger limits for receiving water and groundwater.

Conditions for use of sewage effluent for irrigation.

Requirement for sampling methods to comply with those set out in the latest edition of the

Environmental Protection Agency’s Water Quality Sampling Manual.

It is expected that the amended EA will retain relevant sections related to approval conditions for the kaolin mine as these decommissioning and rehabilitation activities will be ongoing.


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12.4 Environmental Values

12.4.1 Catchments and Watercourses

The Project is situated in the tropics and experiences high rainfall during the wet season and hot, humid conditions during the dry season. In normal years, up to 80 per cent of average annual rainfall occurs as a result of tropical cyclonic events during the wet seasonal months of December to mid-April. However, in exceptionally dry years, rainfall during the wet season months can account for between 80 and 90% of the annual precipitation.

The Project’s mining leases are primarily drained by two drainages – the Skardon River and Namaleta Creek. Regional catchments on Cape York surrounding the Project area are shown in Figure 12-1. The catchments for the Skardon River and Namaleta Creek are shown in Figure 12-2. In addition there are highly localised drainages to the west of the mining leases, which drain the areas between the mining leases and the beach ridges, as shown in Figure 12-2 (catchments 1, 2, 3 and 4). The northern end of the Project is bounded by the Skardon River which drains mangrove areas through three primary tributaries to the south and east.

The Skardon River is considered a predominantly estuarine system, consisting of freshwater systems within its upper reaches. The Skardon River catchment is approximately 480 km2, which is relatively small compared to other catchments on Cape York. The southern tributary of the Skardon River catchment (Catchment 7 in Figure 12-2) is approximately 171.5 km2. Estuarine conditions continue upstream into the southern tributary (Skardon River South Arm) for approximately 9.3 km from its confluence with the main Skardon River Estuary. In the Project area, areas of mining are within the catchment of this estuarine reach of the Skardon River only (i.e. they are not within the catchments of the freshwater parts of the Skardon River).

Namaleta Creek is a localised drainage with a catchment of 37 km2, of which 21 km2 lies upstream of the eastern mine boundary. This watercourse is tidally influenced, where mangrove communities begin approximately 1 km west (downstream) of the existing crossing of Namaleta Creek. The ephemeral system rises from the north and east and eventually discharges to the south into Port Musgrave. An unnamed drainage feature of Namaleta Creek (referred to as Tributary 1) is situated between Pits 14 and 15 to the south of the existing crossing of Namaleta Creek.

ML 6025

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No warranty is given in relation to the data (including accuracy, reliability, completeness or suitability) and accept no liability (including without limitation, liability in negligence) for any loss, damage or costs (including consequential damage) relating to any use of or reliance upon the data. Data must not be used for direct marketing or be used in breach of privacy laws. Tenures © Geos Mining (2015). State Boundaries and Towns © Geoscience Australia (2006). Watercourses © Geoscience Australia. Drainage basins © State of Queensland (DNRM 2015). Basemap Sources: Esri, USGS, NOAA.

LegendMining Lease BoundariesMajor WatercoursesRiver Sub-Basins

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No warranty is given in relation to the data (including accuracy, reliability, completeness or suitability) and accept no liability (including without limitation, liability in negligence) for any loss, damage or costs (including consequential damage) relating to any use of or reliance upon the data. Data must not be used for direct marketing or be used in breach of privacy laws. Tenures © Geos Mining (2015). State Boundaries and Towns © Geoscience Australia (2006). Watercourses © Geoscience Australia. Imagery (inset, main): sourced from Gulf Alumina.Imagery (main) Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP, swisstopo, and the GIS User Community.

Legend!( Port of Skardon River

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12.4.2 Wetlands

A number of different wetland mapping systems exist for wetlands in Queensland. Potential wetlands within and surrounding the Project have been mapped by EHP, and are shown in:

Figure 12-3 for EHP WetlandInfo mapping which separates wetlands into marine, estuarine, riverine, lacustrine and palustrine

Figure 12-5 for EHP’s map of referable wetlands showing high ecological significance wetlands and general high ecological significance wetlands (noting that there are no mapped ‘wetland protection areas’)

Figure 12-6 for EHP’s Vegetation Management Act wetlands

Figure 12-7 from the Directory of Important Wetlands in Australia (DIWA), nationally important wetlands as recognised by the Commonwealth (noting that these are not MNES)

The wetland maps demonstrate that similar areas are considered to be wetlands but are given different status and recognition under various legislation and mapping systems.

Downstream of the Project area, Namaleta Creek is shown as containing estuarine water bodies and estuarine regional ecosystems. Immediately downstream and upstream of the Project area, Namaleta Creek is shown as having palustrine waterbodies and palustrine regional ecosystems. There are two small areas of riverine waterbody and lacustrine waterbody on Namaleta Creek. The lacustrine waterbodies are the existing kaolin mine water storage pits. To the west and downstream of the Project area, there are palustrine waterbodies, palustrine regional ecosystems, riverine regional ecosystems and estuarine regional ecosystems. These include Bigfoot Swamp and Lunette Swamp. The Skardon River is mapped as an estuarine waterbody with estuarine regional ecosystems.

There are high ecological significance (HES) wetlands mapped along the Skardon River (including the South Arm); Namaleta Creek downstream of the existing crossing; drainage line of Namaleta Creek in the south east of the Project area between Pit 14 and Pit 15 (Tributary 1); Bigfoot Swamp; and wetlands in the wetland complex to the west of the Project area. There are general ecological significance (GES) wetlands mapped along Namaleta Creek immediately downstream and upstream of the existing crossing; Lunette Swamp and some wetlands in the wetland complex to the west of the Project.

Field surveys have confirmed an inconspicuous wetland zone between the mangroves and the base of the bauxite plateau along the Skardon River South Arm. This area is referred to as the ‘supratidal wetlands to the west of the Skardon River South Arm’ and falls within the mapped HES wetland in this area.

There are two DIWA wetlands - The Skardon River – Cotterell River Aggregation which lies along the Skardon River and within the localised catchments downstream and west of the Project area; and the Port Musgrave Aggregation which covers the Port of Musgrave to the south of the Project and estuarine areas of Namaleta Creek.

For the purpose of describing freshwater wetlands and assessing potential Project impacts, the following wetland groupings have been considered:

Lunette Swamp

Bigfoot Swamp

Namaleta Creek (freshwater sections)

The HES wetlands bisecting Pits 14 and 15

Supratidal wetlands to the west of the Skardon River South Arm

Wetland complexes to the west and north of the Project area.


-8

For the purpose of describing marine and estuarine wetlands and assessing potential Project impacts, the following wetland groupings have been considered:

Skardon River estuarine areas

Namaleta Creek estuarine areas

The hydrology of wetlands and the hydrogeology of the Project area is described in Chapter 13. The wetlands within and surrounding the Project area include several groundwater dependent ecosystems located along drainage lines which comprise valley fill alluvial deposits with underlying shallow aquifer systems. All freshwater wetlands are likely to be recharged by surface water during the wet season and maintained during the dry season by seasonally perched groundwater recharge. All wetlands are considered to be shallow aquifer groundwater dependent ecosystems.

Based on site knowledge, Lunette Swamp and Bigfoot Swamp wetlands dry out during the dry season, except for small ponds at the lower end of Bigfoot Swamp, which can also dry out in some years. Lunette Swamp dries out fairly rapidly, by July 2015 there was no water in Lunette Swamp.

The palustrine wetlands across the Project area are associated with depressions and watercourse drainage lines. In addition to retaining water they are also a repository of soils and sediments that will retain nutrients to support local biodiversity. The detailed nature of partitioning of the various components of the hydrological cycle – rainfall, runoff, recharge and baseflow, as they affect wetlands, is understood at a conceptual level for the area. These wetlands are dependent on surface water and groundwater interaction. The riverine and estuarine wetlands reaches of Namaleta Creek adjacent to the Project and further downstream are affected by the behaviour of runoff and baseflows entering the Creek.

Field ecological surveys have resulted in the delineation of vegetation communities or ‘map units’, which have been used to derive field mapped regional ecosystems (REs) (Refer Chapter 15). State mapped REs have been used to delineate wetlands.. In general field mapped vegetation map units associated with wetlands correspond to State mapped REs and wetlands.

Further information on the wetland vegetation communities is provided in Chapter 15 and Chapter 16.

The identified wetlands are not matters of national environmental significance (MNES). Listed species which are associated with wetlands are described in Chapter 16.

The Ramsar Convention (The Convention on Wetlands of International Importance) is an international treaty for the conservation and sustainable utilisation of wetlands. Australia is a signatory to this convention. The Ramsar List of Wetlands of International Importance now includes 1,950 sites (known as Ramsar Sites). A desktop search of Ramsar Wetlands did not identified any Ramsar wetlands within or adjacent to the Project area.

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No warranty is given in relation to the data (including accuracy, reliability, completeness or suitability) and accept no liability (including without limitation, liability in negligence) for any loss, damage or costs (including consequential damage) relating to any use of or reliance upon the data. Data must not be used for direct marketing or be used in breach of privacy laws. Tenures © Geos Mining (2015). State Boundaries and Towns © Geoscience Australia (2006). Watercourses © Geoscience Australia. Imagery sourced from Gulf Alumina. Queensland Wetland Data Version 3.0 © State of Queensland - Department of Science, Information Technology, Innovation and the Arts (2013).


Mining Lease BoundariesExisting Disturbance FootprintProject FootprintSouthern Haul RoadWatercourses

Water BodiesMarineEstuarineRiverineLacustrinePalustrine

Wetland Regional EcosystemEstuarineRiverinePalustrine

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Figure 12-4

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Revision: R1



Wetlands of Namaleta Creek Catchment- Queensland WetlandInfo Mapping

0 500 1,000 1,500 2,000Meters


!

!

!

!

Queensland

CAIRNS

BRISBANE

TOWNSVILLE

ROCKHAMPTON

±

No warranty is given in relation to the data (including accuracy, reliability, completeness or suitability) and accept no liability (including without limitation, liability in negligence) for any loss, damage or costs (including consequential damage) relating to any use of or reliance upon the data. Data must not be used for direct marketing or be used in breach of privacy laws. Tenures © Geos Mining (2015). State Boundaries and Towns © Geoscience Australia (2006). Watercourses © Geoscience Australia. Imagery sourced from Gulf Alumina. Queensland Wetland Data Version 3.0 © State of Queensland - Department of Science, Information Technology, Innovation and the Arts (2013).


Mining Lease BoundariesExisting Disturbance FootprintProject FootprintSouthern Haul RoadWatercourses

Water BodiesEstuarineRiverineLacustrinePalustrine

Wetland Regional EcosystemEstuarinePalustrine


!(

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LunetteSwamp

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SKARDON RIVER

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8500

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8685

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8690

000

8690

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Figure 12-5

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Referrable Wetlands -Wetland Management Areas



!

!

!

!

Queensland

CAIRNS

BRISBANE

TOWNSVILLE

ROCKHAMPTON

±

No warranty is given in relation to the data (including accuracy, reliability, completeness or suitability) and accept no liability (including without limitation, liability in negligence) for any loss, damage or costs (including consequential damage) relating to any use of or reliance upon the data. Data must not be used for direct marketing or be used in breach of privacy laws. Tenures © Geos Mining (2015). State Boundaries and Towns © Geoscience Australia (2006). Watercourses © Geoscience Australia. Imagery sourced from Gulf Alumina. Wetland Management Areas © State of Queensland (Department of Environment and Heritage Protection) 2014.Wetland Buffer provided by RPS.


Mining Lease BoundariesExisting Disturbance FootprintProject FootprintSouthern Haul Road

WatercoursesWetland Management Area

HES WetlandGES Wetland

NAMALETACREEK

Pit #14

Pit #15 1:20,000


!(

ML 6025

ML 40082 ML40069

BigfootSwamp

LunetteSwamp

NAMALETACREEK

SKARDON RIVER

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8500

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Figure 12-6

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Revision: R1



Vegetation Management ActWetlands and Watercourses



!

!

!

!

Queensland

CAIRNS

BRISBANE

TOWNSVILLE

ROCKHAMPTON

±

No warranty is given in relation to the data (including accuracy, reliability, completeness or suitability) and accept no liability (including without limitation, liability in negligence) for any loss, damage or costs (including consequential damage) relating to any use of or reliance upon the data. Data must not be used for direct marketing or be used in breach of privacy laws. Tenures © Geos Mining (2015). State Boundaries and Towns © Geoscience Australia (2006). Watercourses © Geoscience Australia. Imagery sourced from Gulf Alumina. VM Wetlands & Watercourses © State of Queensland (DNRM 2015). Wetland Buffer provided by RPS.


Mining Lease BoundariesExisting Disturbance FootprintProject FootprintSouthern Haul Road

VMA WatercoursesVMA Wetlands

NAMALETA

CREEK

Pit #14

Pit #15 1:20,000


!(

ML 6025

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NAMALETACREEK

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Figure 12-7

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Revision: R1



Directory of Important Wetlands



!

!

!

!

Queensland

CAIRNS

BRISBANE

TOWNSVILLE

ROCKHAMPTON

±

No warranty is given in relation to the data (including accuracy, reliability, completeness or suitability) and accept no liability (including without limitation, liability in negligence) for any loss, damage or costs (including consequential damage) relating to any use of or reliance upon the data. Data must not be used for direct marketing or be used in breach of privacy laws. Tenures © Geos Mining (2015). State Boundaries and Towns © Geoscience Australia (2006). Watercourses © Geoscience Australia. Imagery sourced from Gulf Alumina. Directory of Important Wetlands © State of Queensland - Department of Environment and Heritage Protection (2014).Wetland Buffer provided by RPS.


Mining Lease BoundariesExisting Disturbance FootprintProject Footprint

WatercoursesDirectory of Important WetlandsSouthern Haul Road

NAMALETACREEK

Pit #14

Pit #15 1:20,000



Page 12-30

12.5 Water Quality Objectives

12.5.1 Environmental Values from EPP Water

These waters of the Project area are considered to be ‘high ecological value’ (waters in which the biological integrity of the water is effectively unmodified or highly valued). The former kaolin mining operations in the Project area, are not considered to have modified physical, chemical or other indicators.

The following EVs listed under the EPP Water are considered relevant to the waters potentially impacted by the Project:

For high ecological value waters - the biological integrity of an aquatic ecosystem.

For waters that may be used for recreation or aesthetic purposes - the suitability of the water for

secondary recreational use or visual recreational use. Secondary use involves boating and fishing.

There are low levels of recreational fishing, and associated camping (not in the Project’s mining

leases), in the Skardon River.

For waters that may be used for producing aquatic foods for human consumption - the suitability of

the water for producing the foods for human consumption. There is very limited use of the waters

for commercial fishing and no production of aquatic foods in the identified waters.

For waters that may be used for drinking water - the suitability of the water for supply as drinking

water. Only one shallow groundwater bore in the Project area is used for drinking water (kaolin

mine camp supply only) and will be the supply source for the Project’s camp. There are no known

human drinking water users of other fresh surface water sources from the identified waters.

For waters that may be used for industrial purposes - the suitability of the water for industrial use.

Shallow groundwater will be used for the Project’s mining operations (e.g. dust suppression). In

addition, surface water and / or groundwater may be used by other nearby proposed mining

operations in the future. The water quality is considered suitable for this purpose.

The cultural and spiritual values of the water. Indigenous people and groups with links to the Project

area have cultural and spiritual connections to the water. In addition to fishing, members of the

Indigenous community use the area for hunting. Namaleta Creek, Skardon River Estuary, Bigfoot

Swamp and Lunette Swamp are all of cultural and spiritual value to the Traditional Owners.

The following EVs listed under the EPP Water are not considered relevant to the waters potentially impacted by the Project:

For waters that may be used for recreation or aesthetic purposes, the suitability of the water for

primary recreational use. Primary recreational use involves full body contact with the water which,

due to the presence of crocodiles and sharks, is highly unlikely to occur.

For waters that may be used for aquaculture - the suitability of the water for aquacultural use.

There is no known existing or proposed aquacultural uses of the identified waters.

For waters that may be used for agricultural purposes - the suitability of the water for agricultural

purposes. There are no known existing uses of the identified waters for agricultural purposes. This

does not preclude the use of these waters at some point in future for agricultural purposes.

12.5.2 Default Water Quality Objectives

As described in Section 12.3.3, the QWQG recommends the use of local water quality objectives developed for appropriate indicators / parameters using monitoring data from local reference sites.


Page 12-30

There is insufficient sampling data for some parameters with which to establish local water quality objectives under the QWQG. The QWQG does not provide guideline values for the region in which the Project is located. In addition, there are no site / waterway specific documents under the EPP Water for the identified waters. Therefore water quality objectives for the identified waters are based on the AWQG, where there is insufficient local water quality data.

The identified waters occur in tropical Australia at altitudes below 50m. The most appropriate AWQG trigger values to use are:

the physico-chemical trigger values for lowland rivers in tropical Australia for slightly disturbed

ecosystems (noting that there are no physico-chemical trigger values for high ecological value

waters)

the physico-chemical trigger values for wetlands in tropical Australia for slightly disturbed

ecosystems (noting that there are no physico-chemical trigger values for high ecological value

waters)

the toxicant trigger values for metal and metalloids to achieve 99% aquatic ecosystem protection

(applicable to high ecological value ecosystems)

the toxicant trigger values for heavy metals and metalloids in livestock drinking water (noting that

there is no current pastoral activity involving the identified waters).

The AWQG trigger values, are provided in Table 12-1 and have also been compared to the release limits and trigger investigation levels provided in the Model Mining Conditions (EHP, 2014) and the receiving waters contaminant trigger levels of the existing environmental authority (kaolin mining). The AWQG does not provide trigger values for certain parameters, as noted in Table 12-1.

Surface water and groundwater quality data, presented in Section 12.6 and Section 12.7 respectively, has been analysed for the 20th, 50th and 80th percentile for comparison to the AWQG values and to provide local water quality objectives where there is sufficient data. The parameters for which there is sufficient data collected to meet the requirements of the QWQGs are described in Appendix 15 and are:

Namaleta Creek freshwater:

electrical conductivity (EC)

pH –

total dissolved solids (TDS

turbidity (NTU)

Other parameters, although not meeting the criteria for local water quality objectives provide a reasonable indication of likely local water quality objectives that will be derived following additional monitoring. Note that one set of draft water quality objectives for all aquifers and surface water systems is not appropriate. For the purpose of nominating water quality objectives for the Project’s environmental management plan (EM Plan) (Appendix 13), separate water quality objectives have been proposed for:

Namaleta Creek, freshwater

Namaleta Creek, estuarine

wetlands

groundwater

Although groundwater data demonstrates variances between water quality at different shallow aquifers in the Project area, one set of water quality objectives is proposed for all groundwater.


Page 12-30

The methodology used for selection of the nominated water quality objectives for the Project is:

1. where there is sufficient data to set local water quality objectives, the 20th, 50th and 80th percentiles from sampling data has been used, and

2. where there is insufficient data to set local water quality objectives the lowest value from either the AWQG or Model Mining Conditions has been selected.

The potential water quality objectives from which default water quality objectives can be selected, where local water quality objective area not available, are presented in Table 12-1.

.


Page 12-17

Table 12-1 Water Quality Trigger Values – AWQG, Model Mining Conditions and Existing EA

Parameter Unit AWQG Trigger Value – Tropical Lowland Rivers

AWQG Trigger Value – Tropical Wetlands

AWQG Trigger Value – Tropical Marine / Estuarine

AWQG Trigger Value – 99% Protection

AWQG Trigger Value – Livestock (cattle)

Model Mining Conditions

Existing EA – Surface water

Existing EA – ground water

Salinity, electrical conductivity (EC)

µS/cm 20 - 250 90 – 900 n/a n/a n/a Site specific - as per

described method

Higher of 900 or the

80th percentile of the

reference site

Higher of 900 or the

80th percentile of

the reference bore,

max 500

TDS = total dissolved solids

mg/L n/a n/a n/a n/a 4000 - 5000 n/a n/a n/a

Turbidity NTU 2 - 15 2 - 200 1 - 20 n/a n/a n/a Higher of 20 or the


reference site

n/a

TSS = total suspended solids

µg/L n/a n/a n/a n/a n/a n/a n/a n/a

pH pH units 6.0 – 8.0 6.0 – 8.0 7 - 8.5 n/a n/a 6.5 – 9.0 Lowest of 7 or the


reference site to

higher of 8.5 or the


reference site

As per surface water

Chl a = chlorophyll a

µg/L 5 10 2 n/a n/a n/a n/a n/a

TP = total phosphorus

µg/L 10 10 - 50 20 n/a n/a n/a n/a n/a

FRP = filterable reactive phosphate

µg/L 4 5 - 25 5 n/a n/a n/a n/a n/a

TN = total nitrogen

µg/L 200 – 300 350 - 1200 250 n/a n/a n/a n/a n/a


Page 12-18









NOx = oxides of nitrogen

µg/L 10 10 30 n/a n/a n/a n/a n/a

NH4+ = ammonium

µg/L 10 10 15 n/a n/a 900 n/a Higher of 15 or the

80th percentile of

the reference bore,

max 500

DO = dissolved oxygen

% saturation

90 - 120 90 - 120 80 - 120

n/a n/a n/a n/a n/a

Chemical oxygen demand

mg/L n/a n/a n/a n/a n/a n/a n/a Higher of 40 or the

80th percentile of

the reference bore

Nitrate Nitrogen, NO3 as N

µg/L n/a n/a n/a n/a n/a 1100 n/a n/a

Nitrite Nitrogen, NO2 as N


Organic Nitrogen (calc)


Total Kjeldahl Nitrogen


Aluminium (total and dissolved)

µg/L n/a n/a 24

27 5000 55 n/a n/a

Arsenic (III) (total and dissolved)

µg/L n/a n/a ID 1 500 n/a n/a n/a

Arsenic (V) (total and dissolved)

µg/L n/a n/a ID 0.8 n/a 13 n/a n/a


Page 12-19









Boron (total and dissolved)

µg/L n/a n/a ID 90 5000 370 n/a n/a

Cadmium (total and dissolved)

µg/L n/a n/a 0.7 0.06 10 0.2 n/a n/a

Chromium (VI) (total and dissolved)

µg/L n/a n/a 0.14 0.01 1000 1.0 n/a n/a

Cobalt (total and dissolved)

µg/L n/a n/a 0.005 ID 1000 90 n/a n/a

Copper (total and dissolved)

µg/L n/a n/a 0.3 1.0 1000 2.0 n/a n/a

Fluoride µg/L n/a n/a ID n/a 2000 2000 n/a n/a

Iron (total and dissolved)

µg/L n/a n/a ID ID NST 300 n/a n/a

Lead (total and dissolved)

µg/L n/a n/a 2.2

1.0 100 4.0 n/a n/a

Manganese (total and dissolved)

µg/L n/a n/a ID 1200 NST 1900 n/a n/a

Mercury (total and dissolved)

µg/L n/a n/a 0.1

0.06 2 0.2 n/a n/a

Molybdenum (total and dissolved)

µg/L n/a n/a ID ID 150 34 n/a n/a

Nickel (total and dissolved)

µg/L n/a n/a 7 8 1000 11 n/a n/a


Page 12-20









Selenium (total and dissolved)

µg/L n/a n/a ID 5 20 10 n/a n/a

Silver (total and dissolved)

µg/L n/a n/a ID 0.02 ND 1 n/a n/a

Uranium(total and dissolved)

µg/L n/a n/a ID ID 200 1 n/a n/a

Vanadium (total and dissolved)

µg/L n/a n/a 50 ID ND 10 n/a n/a

Zinc (total and dissolved)

µg/L n/a n/a 7 2.4 20000 8 n/a n/a

Petroleum hydrocarbons (C6-C9)

µg/L n/a n/a ID ID n/a 20 n/a No visible film or detectable

odour


µg/L n/a n/a ID ID n/a 100 n/a No visible film or detectable

odour


Page 12-21

12.5.3 Proposed Water Quality Objectives

12.5.3.1 Surface Water

Appendix 15 describes the derivation of the proposed water quality objectives for the Project, including the relevant parameters for which water quality objectives have been proposed. Separate water quality objectives have been established for:

Namaleta Creek – freshwater

Namaleta Creek – estuarine

Wetlands

Water quality objectives for Namaleta Creek and wetlands are presented in Table 12-2.


Page 12-22

Table 12-2 Nominated Water Quality Objectives – Namaleta Creek and Wetlands

Parameter Unit Namaleta Creek – Freshwater

Basis for Nomination

Namaleta Creek – Estuarine


Wetlands Basis for Nomination


µS/cm Site data 20th, 50th & 80th percentiles per Appendix 15, Table 3-9.

Site specific local WQOs

Not proposed. Salinity highly variable. See salinity monitoring in Appendix 15.

No default WQO for salinity in estuarine environment

90 AWQG - tropical wetlands


mg/L Site data 20th, 50th & 80th percentiles per Appendix 15, Table 3-9.


To be defined No default WQO available, potentially use same values as freshwater section.

124 No default WQOs available – use site sampling data 80th percentile.

Turbidity NTU Site data 20th, 50th & 80th percentiles per Appendix 15, Table 3-9.


20 ANZECC – tropical Australia (estuaries)

12.0 Site sampling data 80th percentile within the range of AWQG - tropical wetlands (2 – 200 NTU)

TSS mg/L To be defined No default WQO available. Use site specific local WQOs

To be defined No default WQO available. Use site specific local WQOs

n/a n/a

pH pH units Site data 20th, 50th & 80th percentiles per Appendix 15, Table 3-9.


7.0 - 8.5 ANZECC – tropical Australia (estuaries)

5.5 – 8.0 AWQG - tropical wetlands, recognising low pH of sampling data

DO – dissolved oxygen

% saturation

85 - 120 AWQG - tropical rivers

80 - 120 AWQG - tropical estuaries

90 - 120 AWQG - tropical wetlands


µg/L 27 AWQG - 99% 24 Golding et al (2014)1 27 AWQG - 99%

1 Golding et al, Derivation of a Water Quality Guideline For Aluminium In Marine Waters, Environmental Toxicology and Chemistry, Vol. 34, No. 1, pp. 141–151, 2015


Page 12-23

Parameter Unit Namaleta Creek – Freshwater


Namaleta Creek – Estuarine


Wetlands Basis for Nomination


µg/L 1 AWQG - 99% 1

AWQG - freshwater 99% (no marine value)

1 AWQG - 99%


µg/L 0.8 AWQG - 99% 0.8


0.8 AWQG - 99%

Cadmium (total and dissolved) µg/L

0.06 AWQG - 99% 0.7 AWQG - marine 99% 0.06 AWQG - 99%


µg/L 0.01 AWQG - 99% 0.14 AWQG - marine 99% 0.01 AWQG - 99%


µg/L 1 AWQG - 99% 0.3 AWQG - marine 99% 1 AWQG - 99%


µg/L 300


300 Model Mining Conditions

300 Model Mining Conditions


µg/L 1 AWQG - 99% 2.2 AWQG - marine 99% 1 AWQG - 99%


µg/L 1200 AWQG - 99% 1200


1200 AWQG - 99%


µg/L 0.06 AWQG - 99% 0.1 AWQG - marine 99% 0.06 AWQG - 99%


µg/L 8 AWQG - 99% 7 AWQG - marine 99% 8 AWQG - 99%


µg/L 10


50 AWQG - marine 99% 10 Model Mining Conditions


µg/L 2.4 AWQG - 99% 7 AWQG - marine 99% 2.4 AWQG - 99%


Page 12-24

12.5.3.2 Groundwater

Appendix 15 describes the groundwater monitoring program, including selection of parameters for monitoring at various locations, depending on the potential sources of impact or contamination. Appendix 15 describes the basis for selection of water quality objectives, including the use of site data to set local water quality objectives where sufficient data is available.

For water quality bores near mining areas and potential contamination sites (Port area and treated effluent irrigation area at the camp) parameters are noted as:

‘primary concern’ where there may be a direct impact on the parameters

‘secondary concern’ where parameters provide additional information, but which are not

necessarily related to Project impacts and are not proposed as parameters against which

compliance with water quality objectives are measured

‘aquifer characterisation’ where it may be necessary to understand different aquifers with potential

to be contaminated but are not proposed as parameters against which compliance with water

quality objectives are measured.

Some parameters are only relevant for particular aspects being monitored. The table below describes the parameters proposed for monitoring in bores in:

Mining areas

Port area, including landfill and bioremediation pad

Treated effluent irrigation area.

Water quality objectives are only applicable to parameters that are of primary concern for a given monitoring area. Nominated groundwater quality objectives are provided in the table below.


Page 12-25

Table 12-2b Nominated Water Quality Objectives – Groundwater

Parameter Unit Groundwater - Mining Areas

Groundwater - Port area and Landfill

Groundwater – Treated Effluent

Samples (n)

20th percentile

50th percentile

80th percentile

Default WQO

Source


µS/cm primary primary primary 43 36.00 52.00 101.60 Site data


mg/L primary secondary secondary 54 18.80 47.00 120.00 Site data

Turbidity NTU primary secondary secondary 46 2.50 28.50 60.00 Site data

TSS = total suspended solids

mg/L not monitored primary primary - 30 Model Mining Conditions

pH pH units primary primary primary 54 5.30 5.50 5.83 Site data

Chl a = chlorophyll a

µg/L not monitored primary primary - 5 AWQG - tropical rivers

TP = total phosphorus

µg/L not monitored primary primary 54 20.00 40.00 110.00 Site data

TN = total nitrogen µg/L not monitored primary primary 54 80.00 160.00 324.00 Site data

DO = dissolved oxygen

% saturation primary primary primary 8 21.98 25.45 37.38 Site data

Chemical oxygen demand

mg/L not monitored primary primary - 40 AWQG - aquaculture

Nitrate Nitrogen, NO3 as N

µg/L not monitored primary primary - 1100 Model Mining Conditions

Nitrite Nitrogen, NO2 as N

µg/L not monitored primary primary - 100 AWQG - aquaculture


µg/L primary primary not monitored 54 9.80 16.00 27.60 27 Dissolved site data > AWQG - 99%


µg/L primary not monitored not monitored 21 1.00 1.00 1.40 1 Unspeciated dissolved site data > AWQG - 99%


µg/L primary not monitored not monitored 21 1.00 1.00 1.40 0.8 Unspeciated dissolved site data > AWQG - 99%

Cadmium (total and dissolved)

µg/L primary primary not monitored 14 All below LOR = 0.1

0.06 AWQG - 99%


µg/L primary not monitored not monitored 38 1.00 1.00 1.60 0.01 LOR = 1, dissolved site data > AWQG - 99%


Page 12-26




Samples (n)

20th percentile

50th percentile

80th percentile

Default WQO

Source






µg/L primary primary not monitored 36 1.00 1.00 1.20 1 LOR = 1, dissolved site data > AWQG - 99%


µg/L primary primary not monitored 54 2.40 8.00 19.20 1200 AWQG - 99%


µg/L primary not monitored not monitored 54 All below LOR = 0.05

0.06 AWQG - 99%


µg/L primary not monitored not monitored 41 1.00 2.00 7.00 8 AWQG - 99%


µg/L primary not monitored not monitored 10 Model Mining Conditions


µg/L primary primary not monitored 52 18.00 43.00 90.80 2.4 Dissolved site data > AWQG - 99%


µg/L not monitored primary not monitored - 20 Model Mining Conditions


µg/L not monitored primary not monitored - 100 Model Mining Conditions

Ammonia (NH3) µg/L not monitored primary primary - 15 Existing EA

Biochemical oxygen demand (BOD)

mg/L not monitored primary primary - 15 AWQG - aquaculture

E-coli Organisms/ 100 mL

not monitored primary primary - 1000 Existing EA

total organic carbon mg/L not monitored primary not monitored No data No data compare to upgradient bore

Toluene (bioremediation pad only)

µg/L not monitored primary not monitored n/a 600 AWQG - 99%

Ethylbenzene (bioremediation pad only)

µg/L not monitored primary not monitored n/a No data compare to upgradient bore


Page 12-27




Samples (n)

20th percentile

50th percentile

80th percentile

Default WQO

Source

Xylene (bioremediation pad nly)

µg/L not monitored primary not monitored n/a No data compare to upgradient bore

Naphthalene (bioremediation pad only)

µg/L not monitored primary not monitored n/a 140 AWQG - 99%

Tolune (bioremediation pad only)

µg/L not monitored primary not monitored n/a 2.5 AWQG - 99%


Page 12-28

12.6 Surface Water Monitoring

12.6.1 Surface Water Monitoring Locations

Surface water monitoring has occurred intermittently in the Project area over the past 25 years, primarily to identify potential impacts of the former kaolin mine operations. Surface water monitoring has occurred at the locations listed in Table 12-3 and shown in Figure 12-8. Surface water monitoring sites have been assigned different names over the course of kaolin mining activities. These historical names are provided in Table 12-3, including noting monitoring site names under the current environmental authority.

Surface water level monitoring was undertaken from mid 2014 at S10 and S11, and from early 2015 at S1, S8 and S9.

Monitoring of physical parameters (pH and EC) has been undertaken at most sites since early 2008, with more comprehensive monitoring including selected metals and nutrients since February 2015.

During 2015, surface water monitoring comprised 10 locations across the Project area. Water quality parameters measured in the field include pH, EC, TDS, turbidity, DO and redox. In addition there were laboratory determinations of selected metals. Laboratory analysis was undertaken by a NATA accredited laboratory. There was limited testing for nutrients, which is of limited value as baseline data, but has been included for completeness.

Note that sites S3, S4 and S5 are located within the existing kaolin mine water storage pits and hence water quality at these sites is not representative of ambient / baseline water quality in natural systems, and is therefore presented separately below. Site S13 monitors water quality from releases from the existing Port sediment pond, which are extremely limited to date and do not provide representative baseline water quality, and hence data is not provided for this site.

Marine water quality data is presented in Chapter 17. Site S7 has limited marine water quality from the estuarine section of Namaleta Creek. Site S14 has had limited sampling from the marine / estuarine environment at the Port, but will be the release monitoring site for the proposed Port sediment pond proposed for the Project. Data for site S7 and S14 is not presented. Sites S7, S22 and S21 (Figure 12-17) are proposed for ongoing estuarine water quality sampling in Namaleta Creek. Site S18 and site S19 are proposed for monitoring of the supratidal wetland along the Skardon River South Arm. Site S21 and Site S22 are proposed for monitoring of Tributary 1. Sites S15, S16 and S17 will form part of the Skardon River marine monitoring plan described in Chapter 17.

Table 12-3 Surface Water Monitoring Data

Site Number

Historical Site Name

Easting Northing Creek / Water Body Water Level Data

Water Quality Data

S1 Nam-1 610491 8685825 Namaleta Creek upstream of all proposed mining

from January 2015

from February 2015

S2 Upstream Water Pit (per EA)

609949 8686287 Namaleta Creek upstream of kaolin mine, downstream of some bauxite mining

n/a from January 2008

S3 W1 (per EA) – discharge point from raw water pit

609803 8686458 Raw Water Pit n/a from January 2008


Page 12-29

Site Number

Historical Site Name

Easting Northing Creek / Water Body Water Level Data

Water Quality Data

S4 n/a 609937 8686458 Raw Water Pit n/a from January 2008

S5 W6 (per EA) – discharge point from western sump of fluvial Pit

609409 8686750 Fluvial Pit n/a from January 2008

S6 Namaleta Downstream (per EA)

609392 8686912 Namaleta Creek, downstream of kaolin and bauxite mining

n/a from January 2008

S7 n/a 607021 8685776 Namaleta Creek (estuarine), downstream of kaolin and bauxite mining

n/a From July 2015

S8 Nam-3 609654 8686412 Namaleta Creek, downstream of existing Creek crossing

from January 2015

n/a

S9 Namaleta Crossing Down, Nam-2

609644 8686416 Namaleta Creek, upstream of existing Creek crossing

from January 2015

from January 2008

S10 Lunette 1 612039 8688649 Lunette Swamp from July 2014

from February 2015

S11 Bigfoot 1 612860 8695847 Bigfoot Swamp from July 2014

from March 2015

S12 n/a 611778 8690224 Lunette Swamp, downstream

n/a from June 2015

S14 n/a 616639 8700156 Skardon River (estuarine) n/a from June 2015

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!>

!>

!>

!>

ML 6025

ML 40082

ML 40069

SKARDON RIVER

NAMALETA CREEK

S15

S16

S7

S12

S10(Lunette 1

/ S1)

S11 (Bigfoot1 / NorthernHole / S2)

605000 610000 61500086

8500

0

8685

000

8690

000

8690

000

8695

000

8695

000

8700

000

8700

000

Figure 12-8

G:\CLIENTS\E-TO-M\Gulf Alumina\GIS\Maps\EIS\Ch12_WaterQuality\FIG_12_08_SWMP_Locations_160315.mxd

Revision: R1



Surface Water MonitoringLocations



!

!

!

!

Queensland

CAIRNS

BRISBANE

TOWNSVILLE

ROCKHAMPTON

±

No warranty is given in relation to the data (including accuracy, reliability, completeness or suitability) and accept no liability (including without limitation, liability in negligence) for any loss, damage or costs (including consequential damage) relating to any use of or reliance upon the data. Data must not be used for direct marketing or be used in breach of privacy laws. Tenures © Geos Mining (2015). State Boundaries and Towns © Geoscience Australia (2006). Watercourses © Geoscience Australia. Imagery © ESRI (2015).

LegendMining Lease Boundaries

!( Port of Skardon RiverWatercourses

Surface Water Monitoring Locations!> Depth logger!> Marine water quality!> Water quality!> Water quality and depth logger

!>

!>

!>

!>

!>

!>

!>!>

S4 (Pit-1/ S6)S3 (W1 (EA))

S2 (UpstreamWater Pit

(EA))

S6

S8 (Nam-3/ S5)

S1 (Nam-1/ S3)

S5 (W6(EA) /

Pit-2 / S7)

S9(Nam-2 / S4)

!(

!>

!>

!> S17

S13 (W2(EA))

S14

1:30,000

1:30,000


Page 12-31

12.6.2 Surface Water Level Data

Results of surface water level logging are provided in Table 12-4, and illustrated in graphs in Appendix 4, with an example for site S8 presented in Figure 12-9. Surface water level graphs for Lunette Swamp and Bigfoot Swamp are presented in Appendix 15. These graphs also show rainfall during the monitoring period. There are some data spikes and drop outs noted in the data, these are likely due to the retrieval of the logger for downloading of data. These irregularities have been filtered from the data for the purpose of interpretation in this report.

The surface water level records have not been reduced to any local survey datum. Hence, surface water data records refer to water surface depths above the logger level. Despite this, the data is useful in understanding the seasonal variation in water levels and the response to rainfall events.

Surface water level in all locations is seasonally variable, with elevated water levels in the period February to March each year, co-incident with the wet season. The variation in water level between wet and dry seasons is between 0.88 to 4.2m, depending on the location. It is noted that water level responds very directly to rainfall, with an almost immediate response in water level to rainfall events apparent in Namaleta Creek. The response to rainfall of the sites in Lunette Swamp and Bigfoot Swamp is more subdued.

Table 12-4 Surface Water Levels

Site Number Location Minimum Water Level (m)

Maximum Water Level (m)

Seasonal Water Level Range (m)

S1 Namaleta Creek 0.35 1.23 0.88



S10 Lunette Swamp 0.0 4.20 4.2

S11 Bigfoot Swamp 0 3.0 3.0

Figure 12-9 Site S8 Surface Water Level and Rainfall


Page 12-32

12.6.3 Surface Water Quality

The results of surface water quality testing are tabulated and graphed in Appendix 4. The physical parameters from surface water monitoring has been summarised by the location, either Namaleta Creek, the wetlands (Lunette Swamp and Bigfoot Swamp) or kaolin water storages (Raw Water Pit and Fluvial Pit).

Physical parameter data from surface water has been obtained from Namaleta Creek over four wet seasons, and thus there is enough data to propose statistically valid site specific trigger values in accordance with the AWQG for a limited number of parameters (EC, pH, TDS and turbidity). The bulk of the trace metal and nutrient surface water quality data for Namaleta Creek has been obtained during a four month period of 2015. Thus, there is not enough data to propose statistically valid site specific trigger values for metals and nutrients in accordance with the AWQG. Despite this, there is sufficient data to make some initial interpretation of the surface water quality onsite.

12.6.3.1 Physical Parameters

Physical parameters for Namaleta Creek, the wetlands and kaolin water storages are presented in Table 12-5, Table 12-6 and Table 12-7 respectively. Note that there was not enough data for dissolved oxygen and redox for valid statistics.

pH is moderately acidic to neutral, ranging from 4.08 to 7.03 pH units. The weakly acidic pH is a reflection of the geology of the catchment.

EC is low, ranging from 16 to 440 µS/cm. The majority of EC is very low, with the 80th percentile value of 50 µS/cm for Namaleta Creek, 32 µS/cm for the wetlands and 97 µS/cm for the kaolin water stoarges. It is noted that elevated values can be recorded at site S6 (including the maximum of 440 µS/cm) and this is interpreted to occur due to evaporation, coincident with the dry season (hence low water levels in Namaleta Creek).

Table 12-5 Surface Water Physical Parameter Summary Results – Namaleta Creek

Sites Statistical Element pH (pH units) EC (µS/cm) TDS (mg/L) Turbidity (NTU)

S1, S2, S6, S8, S9 minimum 4.08 16.2 11 0

maximum 7.03 440 92 30.3

mean 5.15 46.10 25.97 3.56

median 5.04 32.85 21 2.645

20th percentile 4.78 25.00 16 1.50

80th percentile 5.45 50.02 31 4.51

n 124 128 46 134

Table 12-6 Surface Water Physical Parameter Summary Results – Wetlands


S10, S11, S12 minimum 5.6 18 18 1.4

maximum 6.2 35 200 140

mean 5.88 28 73.57 16.83

median 5.90 30.00 64.00 2.15

20th percentile 5.70 23.80 27.60 1.76

80th percentile 6.02 32.40 94.00 4.56

n 10 7 10 10

Table 12-7 Surface Water Physical Parameter Summary Results – Kaolin Water Storages


S3, S4, S5 minimum 4.58 25.40 0 0.9

maximum 7.13 162.00 105 310.0


Page 12-33


mean 5.50 81.47 49 22.3

median 5.41 83.20 50 14.9

20th percentile 5.06 62.80 41.8 7.78

80th percentile 5.83 97.24 53 28.9

n 116 117 44 99

12.6.3.2 Metals

Monitoring data for selected metals has been obtained, and is summarised in Table 12-8, Table 12-9 and Table 12-10 for Namaleta Creek, the wetlands and the kaolin water storages respectively. Dissolved metals values are very low across almost all sites, when compared with the AWQG. Most samples results are below the detection limit. Two exception are:

dissolved aluminium, which is variable and has a maximum of 0.1 mg/L in Namaleta Creek, 0.2 mg/L

in the wetlands and 0.08 mg/L in the kaolin water storages (compared to 0.027 mg/L per the AWQG)

dissolved copper, which is variable and has a maximum of 0.003 mg/L in Namaleta Creek, 0.004

mg/L in the wetlands and 0.002 mg/L in the kaolin water storages (compared to 0.001 mg/L per the

AWQG).

It is considered that these values of metals reflect the geology of the site.

Table 12-8 Surface Water Dissolved Metals Summary Results –Namaleta Creek

Sites Statistical Element

Al (mg/L)

As (mg/L)

Cd (mg/L)

Cr (mg/L)

Cu (mg/L)

Fe (mg/L)

Pb (mg/L)

Mn (mg/L)

Hg (mg/L)

Ni (mg/L)

Zn (mg/L)

S1,S2, S6, S8, S9

minimum 0.017 n/a n/a n/a 0.001 0.013 n/a 0.001 n/a n/a n/a

maximum 0.1 n/a n/a n/a 0.003 0.151 n/a 0.003 n/a n/a n/a

mean 0.0353 n/a n/a n/a 0.0017 0.0602 n/a 0.0022 n/a n/a n/a

median 0.025 n/a n/a n/a 0.0015 0.0435 n/a 0.002 n/a n/a n/a

80th percentile

0.0502 n/a n/a n/a 0.0042 0.1044 n/a 0.003 n/a n/a n/a

n 13 4 4 5 10 14 4 13 14 14 6

n/a - Results all below the detection limit, or not enough results for valid statistics.

Table 12-9 Surface Water Dissolved Metals Summary Results – Wetlands

Bores Statistical Element

Al (mg/L)

As (mg/L)

Cd (mg/L)

Cr (mg/L)

Cu (mg/L)

Fe (mg/L)

Pb (mg/L)

Mn (mg/L)

Hg (mg/L)

Ni (mg/L)

Zn (mg/L)

S10, S11, S12

minimum 0.011 n/a n/a n/a 0.001 0.029 n/a 0.003 n/a n/a n/a

maximum 0.201 0.001 n/a n/a 0.004 8.96 n/a 0.309 n/a n/a n/a

mean 0.0941 n/a n/a n/a 0.002 0.9829 n/a 0.0553 n/a n/a n/a

median 0.094 n/a n/a n/a 0.0015 0.085 n/a 0.0045 n/a n/a n/a

80th percentile

0.13 n/a n/a n/a 0.0028 0.1694 n/a 0.008 n/a n/a n/a

n 10 6 3 5 9 10 5 10 10 6 6


Table 12-10 Surface Water Dissolved Metals Summary Results – Kaolin Water Storages


Al (mg/L)

As (mg/L)

Cd (mg/L)

Cr (mg/L)

Cu (mg/L)

Fe (mg/L)

Pb (mg/L)

Mn (mg/L)

Hg (mg/L)

Ni (mg/L)

Zn (mg/L)

S3, S4, S5

minimum 0.011 n/a n/a n/a 0.001 0.015 n/a 0.001 n/a n/a 0.005

maximum 0.078 n/a n/a n/a 0.002 0.048 n/a 0.002 n/a n/a 0.005

mean 0.032 n/a n/a n/a 0.0015 0.032 n/a 0.001 n/a n/a 0.005

median 0.025 n/a n/a n/a 0.0015 0.033 n/a 0.001 n/a n/a 0.005


Page 12-34


Al (mg/L)

As (mg/L)

Cd (mg/L)

Cr (mg/L)

Cu (mg/L)

Fe (mg/L)

Pb (mg/L)

Mn (mg/L)

Hg (mg/L)

Ni (mg/L)

Zn (mg/L)

80th percentile 0.0494

n/a n/a n/a 0.0018 0.038

n/a 0.001

n/a n/a 0.005

n 8 0 0 3 4 8 1 7 8 0 2


12.6.3.3 Nutrients

Monitoring data for total nitrogen (TN) and total phosphorus (TP) has been obtained, and is summarised in Table 12-11, Table 12-12 and Table 12-13 for Namaleta Creek, the wetlands and the kaolin water storages respectively. Nutrient values (TN, TP) are low across all sites. It is generally noted that nutrients within the wetlands are an order of magnitude higher than levels recorded in Namaleta Creek. These elevated nutrient levels will be taken into account during longer term monitoring and management of site activities.

Table 12-11 Surface Water Nutrient Summary Results – Namaleta Creek

Sites Statistical Element Nitrogen (total) (mg/L N) Phosphorus (total) (mg/L P)

S1,S2, S6, S8, S9 minimum 0.05 n/a

maximum 0.16 n/a

mean 0.1008 n/a

median 0.095 n/a

80th percentile 0.15 n/a

n 14 14

Table 12-12 Surface Water Nutrient Summary Results - Wetlands

Bores Statistical Element Nitrogen (total) (mg/L N) Phosphorus (total) (mg/L P)

S10, S11, S12 minimum 0.11 0.02

maximum 2.4 0.28

mean 0.516 0.11

median 0.305 0.07

80th percentile 0.582 0.178

n 10 10

Table 12-13 Surface Water Nutrient Summary Results - Kaolin Water Storages

Bores Statistical Element Nitrogen (total) (mg/L N) Phosphorus (total) (mg/L P)

S3, S4, S5 minimum 0.05 n/a

maximum 0.26 n/a

mean 0.133 n/a

median 0.12 n/a

80th percentile 0.148 n/a

n 8 8

12.7 Groundwater Monitoring

12.7.1 Groundwater Monitoring Locations and Parameters

Groundwater monitoring has occurred intermittently in the Project area over the past 25 years, primarily to support the former kaolin mine operations. However in the past 2 to 3 years groundwater monitoring (including groundwater level and quality) has also been undertaken to understand the reliability of water supply from shallow aquifers for the Project. In addition, groundwater quality


Page 12-35

monitoring was undertaken in April 2015, June 2015 and July 2015 to provide additional data to support this EIS.

In order to avoid creating turbidity in clear water and thereby provide more consistent and accurate sampling of more representative samples, the sampling methodology for groundwater was undertaken using the low-flow sampling and purging guidelines described in QED Environmental Systems Inc: Low-Flow Ground-Water Sampling: Latest Research and Equipment Options (2014).

High purge volume sampling in low yield bores (such as those encountered within the Project area), can cause:

an underestimation of maximum contaminant concentrations (due to dilution),

an overestimation of contaminant concentrations due to contaminant mobilization and increased

sample turbidity (e.g. turbidity can elevate metals and some organics bound to solids (e.g.

polyaromatic hydrocarbons),

losses of volatile organic compounds, affected DO and carbon dioxide levels, and

increased sample turbidity.

Groundwater monitoring has occurred at the locations listed in Table 12-14 and shown in Figure 12-10. Over the history of the mining leases dating back to the 1990’s groundwater bores have been given alternative naming conventions. The alternative naming conventions are shown in Table 12-14.

During 2015, groundwater monitoring within and surrounding the Project area comprised 14 bores located on Gulf Alumina’s mining tenements (including exploration tenements adjoining the Project area) and 3 bores on Metro Mining’s adjoining tenements. Monitoring of these bores includes continual measurement with logging equipment of the standing water levels (and in some cases of physical parameters), and water quality sampling on a monthly basis (from April 2015). Table 12-14 summarises the details of the groundwater bores monitored on site. Water quality parameters measured in the field included pH, EC, TDS, DO and redox. In addition there were laboratory determinations of pH, EC, TDS, and selected metals. There was limited testing for nutrients, ions and hydrocarbons, which is of limited value as baseline data, but has been included for completeness.

Note that the C1, C2 and C3 bores are nested, with a shallow bore screened in the Bulimba Formation and a deep bore screened in the Rolling Downs Siltstone in each case. The depth logger is installed in the deep bore, while water quality samples have been taken from both the shallow and deep bores.

The hydrogeology of the Project area, including a description of the aquifers, is provided in Chapter 13, Section 13.5. The aquifers for which monitoring data was obtained are, in order of depth from oldest to youngest, the Rolling Downs Formation, Bulimba Formation and alluvium, valley cut and fill deposits. The Namaleta aquifer is considered to be a meandering palaeochannel within these valley systems and is described as ‘Bulimba Formation (Namaleta Creek) aquifer’ when discussing monitoring data below. For the purpose of this study, the aquifer monitored by the individual bores has been noted.

As noted in Chapter 13, studies were undertaken for the kaolin mine in the 1990s by Rockwater Pty Ltd (1994), Golder Associates Pty Ltd (1998) and Douglas and Partners Pty Ltd (1995) that are particularly relevant to developing understandings of the shallow aquifers.

Bore logs for existing bores were obtained from Golder Associates Pty Ltd (1998) for bores G1, G3, G4, G5, G12, G13, G14. Bores logs for bores drilled by Cape Alumina Pty Ltd (Metro Mining Ltd) were obtained for C1, C2 and C3. Bore log records from drilling campaigns in 2014 were obtained for G6, G7, G8, G9, G10 and G11. These bore logs, in combination with the understanding of the hydrogeology of the area were used to identify the formation which the aquifers are screened. Table 12-14 provides the formation in which aquifers are screened with bores separated into:


Page 12-36

Bulimba formation – alluvial deposits adjacent Namaleta Creek (also referred to as Bulimba

Formation (Namaleta aquifer))

Bulimba formation

Rolling Downs Siltstone

Bulimba Formation - Lunette sand aquifer (bore G1 only).

Additional bores (G15, G16, G17, G18, G29 and G30) have been proposed surrounding the Project area to provide baseline, upgradient information and to identify potential impacts in various aquifers. The formations in which these bores are proposed to be screened are provided in Table 12-14. Bores will be installed to monitor the appropriate aquifers within the vertical profile to meet the targeted monitoring requirements. The function of these bores is described in Table 12-30.

In relation to existing and proposed bores:

Bigfoot Swamp – Bores G9 and G10 are located in the Bulimba formation up-catchment from

Bigfoot Swamp. They will provide information on conditions in the areas during mining. Bore C2 is

located to the north and east of the swamp and will monitor conditions in the lower down the

catchment. A further bore is proposed (G29) to record groundwater levels below the Bigfoot Swamp

in the paleochannel.

Lunette Swamp – Monitoring bore G1 is screened in the Lunette sand aquifer. Bores C1 and G8 will

provide groundwater level information adjacent to Lunette Swamp. A further bore is proposed

(G30) to record groundwater levels below the swamp in the paleochannel.

Namaleta Creek – G12, G13 and G14 are local monitoring bores in the lateritic aquifer adjacent

Namaleta Creek that are believed to be in hydraulic continuity with the alluvial material and the

Namaleta sand aquifer system. Bores G2, G4 and G18 (proposed) will log groundwater levels higher

up the catchment on the banks of the Namaleta Creek.

Skardon River supratidal wetland – the bores included in the monitoring network to address

monitoring of conditions include bores G9, G10, G11 and C3, which are screened in the Bulimba

formation.


Page 12-37

Table 12-14 Groundwater Monitoring Data

Bore Number

Alternative Bore Name

Easting (m)

Northing (m)

Ground Level (m, AHD)

Casing Height (m)

Total Depth (m)

Formation Aquifer Screened

Water Level Data

Water Quality Data

G1 Camp bore, Gulf 1, AKP01

611810 8687604 11.287 0.67 18.385 Bulimba Formation; Lunette sand aquifer

Slotted uPVC: 3-9 mbgl; Slotted stainless steel: 9-12 mbgl

from Nov 2013

from February 2015

G2 Gulf 3, EMB01

610596 8687043 9.886 0.48 15.000 Bulimba Formation; alluvial deposits adjacent Namaleta Creek

Slotted uPVC: approx. 11 to 14 mbgl

from Nov 2013

from April 2015

G3 Gulf 4, AKM10


Slotted uPVC: 4-12 mbgl

from Nov 2013

from April 2015

G4 Gulf 6, AKM19s



from Nov 2013

from April 2015

G5 Gulf 5, AKM26, G10 (per EA)

616612 8699558 3.335 0.57 10.800 Bulimba Formation Slotted uPVC: 4-10 mbgl

from Nov 2013

from April 2015

G6 GMB2 608861 8688522 7.371 0.47 12.500 Bulimba Formation Slotted uPVC: 6-8 mbgl

from August 2014

from April 2015

G7 GMB6 606990 8688615 6.575 0.44 10.570 Bulimba Formation Slotted uPVC: approx. 6-10 mbgl

from August 2014

from April 2015


Page 12-38

Bore Number


Easting (m)

Northing (m)


Casing Height (m)

Total Depth (m)


Water Level Data

Water Quality Data

G8 GMB1 609603 8690668 7.149 0.45 11.190 Bulimba Formation Slotted uPVC: approx. 6-10 mbgl

from August 2014

from April 2015

G9 GMB3 614121 8692982 11.174 0.50 14.185 Bulimba Formation Slotted uPVC: 11.75-14.75 mbgl

from August 2014

from April 2015


from August 2014

from April 2015


n/a from April 2015

G12 AKM09 609468 8686946 n/a 0.46 18.480 Bulimba Formation; alluvial deposits adjacent Namaleta Creek


n/a from July 2015



n/a from July 2015



n/a from July 2015

C1 Cape 1, BH6 MB1 D 101

612629 8690559 11.926 0.50 22.120 Rolling Downs Siltstone

Slotted uPVC: approx.. 15-21 mbgl

from March 2014

from March 2015


Page 12-39

Bore Number


Easting (m)

Northing (m)


Casing Height (m)

Total Depth (m)


Water Level Data

Water Quality Data



Slotted uPVC: 13.8-19.8 mbgl

from March 2014

from March 2015




from March 2014

from March 2015

G15 proposed

614307 8689722 To be drilled To be drilled To be drilled

Bulimba Formation To be drilled

n/a n/a

G16 proposed



n/a n/a

G17 proposed



n/a n/a

G18 proposed


Namaleta sand aquifer system/Bulimba formation

To be drilled

n/a n/a

G29 proposed


Bigfoot Swamp alluvial sand aquifer

To be drilled

n/a n/a

G30 proposed


Lunette Swamp alluvial sand aquifer

To be drilled

n/a n/a

!(

!>

!>!>

!>

!>

!>

!>

!>

!> !>

!>

!>!>!>

!>

!>

!>

ML 6025

ML 40082

ML 40069

SKARDON RIVER

NAMALETA CREEK

G1(Gulf 1 /Gulf 2 /AKP01)

G8(G-MB1)

G6(G-MB2)

G9 (G-MB3)

G10(G-MB4)

G11(G-MB5)

G7(G-MB6)

C1 (Cape 1 /BH6 MB1 D 101)

C2(Cape 2 /

BH6 MB2 D 419)

C3(Cape 3 /

BH6 MB3 D 230)

605000 610000 61500086

8500

0

8685

000

8690

000

8690

000

8695

000

8695

000

8700

000

8700

000

Figure12-10

G:\CLIENTS\E-TO-M\Gulf Alumina\GIS\Maps\EIS\Ch12_WaterQuality\FIG_12_10_GWMP_Locations_160315.mxd

Revision: R1



Groundwater MonitoringLocations



!

!

!

!

Queensland

CAIRNS

BRISBANE

TOWNSVILLE

ROCKHAMPTON

±




!> Groundwater Monitoring Locations

!>

!>

!>

!>

!>!>

G2 (Gulf 3/ EMB02)

G3(Gulf 4 / AKM10)

G4(AKM19s)

G14(AKM07)

G13(AKM08)

G12(AKM09)

NAMALETACREEK

!(

!>G5 (AKM26/ G10(EA))

1:30,000

1:30,000


Page 12-41

12.7.2 Groundwater Levels

Results of groundwater level logging are tabulated and graphed in Appendix 4 and Appendix 15 for all bores Groundwater levels are summarised in Table 12-15 and graphs are presented for bore C1 in Figure 12-11 and bore G3 in Figure 12-12. These graphs are representative of trends in groundwater levels observed in all bores.

The graphs show rainfall during the monitoring period. There are some data spikes and drop outs noted in the graphs, these are likely due to the retrieval of the logger for downloading of data. These irregularities have been filtered from the data for the purpose of groundwater interpretation in this report.

Groundwater level in all aquifers is seasonally variable, with elevated groundwater levels in the period February to March each year, co-incident with the wet season. The variation in groundwater level between wet and dry seasons is between 3.9 to 10.04 m, depending on the bore. Groundwater level responds very directly to recharge from rainfall, with an almost immediate response in groundwater level to rainfall events apparent in all bores in Bulimba Formation aquifers. The response to rainfall of the bores in the Rolling Downs Siltstone aquifer is more subdued.

Table 12-15 Groundwater Level Data

Bore Number

Aquifer Minimum Water Level (m, AHD)

Maximum Water Level (m, AHD)

Seasonal Water Level Range (m)

G1 Bulimba Formation 2.67 10.52 7.85


G3 Bulimba Formation (adjacent Namaleta Creek)

-2.20 4.84 7.04


-1.63 2.30 3.93

G5 Bulimba Formation -0.81 3.20 4.01

G6 Bulimba Formation n/a n/a n/a

G7 Bulimba Formation -1.29 4.29 5.85




G11 Bulimba Formation n/a n/a n/a


n/a n/a n/a


n/a n/a n/a


n/a n/a n/a

C1 Rolling Downs Siltstone 1.71 11.75 10.04



n/a = not enough valid data to determine the response


Page 12-42

Figure 12-11 Standing Groundwater Level – Bore C1

Figure 12-12 Standing Groundwater Level – Bore G3

12.7.3 Groundwater Quality

The results of groundwater quality testing are tabulated and graphed in Appendix 4. Groundwater quality results are presented for all aquifers in combination and the different aquifers which are intersected by the bores, namely Bulimba Formation (Namaleta Creek) aquifer, Bulimba Formation aquifer and Rolling Downs Siltstone aquifer. Each aquifer has three or more bores screened within that


Page 12-43

aquifer, which can be considered ‘reference sites’. In general, the number of samples for each parameter within each aquifer ranges between 8 and 32 (Table 12-16). This is considered adequate for interim characterisation of the baseline water quality of physico-chemical, metal and nutrient parameters, with the 20th, 50th (median) and 80th percentiles presented in Table 12-16 to Table 12-27.

12.7.3.1 Physical Parameters

The physical parameters determined from the groundwater monitoring have been summarised in Table 12-16, Table 12-17, Table 12-18and Table 12-19 for the three different aquifer groupings.

pH is slightly acidic in all aquifers, ranging from 4.8 to 6.2 pH units. The weakly acidic pH is a reflection of the geology of the site.

EC is low, ranging from 22 to 196 µS/cm. Bores within the Bulimba Formation aquifer have the lowest mean EC (59 µS/cm), with bores in the Rolling Downs Siltstone aquifer have mean EC (74 µS/cm), and the bores within the Bulimba Formation aquifer adjacent to Namaleta Creek have highest mean EC (126 µS/cm).

Of the bores intersecting the Bulimba Formation aquifer, bores G3, G5, G12 and G13 have elevated EC (>100 µS/cm) when compared with the remainder of the bores. This may be due to their proximity to tidally influenced portions of Namaleta Creek (G3, 12, 13, 14) and Skardon River (G5).

Table 12-16 Groundwater Physical Parameter Summary Results – All Bores


pH (pH units) EC (µS/cm) TDS (mg/L) DO (mg/L) Redox (mV)

All Bores minimum 4.80 27.00 5.00 1.63 53.00

maximum 6.22 196.00 970.00 4.32 256.00

mean 5.52 74.23 122.09 2.34 200.00

median 5.50 52.00 47.00 1.95 228.00

80th percentile

5.83 101.60 120.00 2.82 249.00

n 54 43 54 8 8

20th percentile

5.30 36.00 18.8 1.69 160.80

Table 12-17 Groundwater Physical Parameter Summary Results – Bulimba Formation (Namaleta Creek) Aquifer



G3, G4, G12, G13, G14

minimum 5.02 69 44 n/a n/a

maximum 6 196 970 n/a n/a

mean 5.41 126.3 216 n/a n/a

median 5.33 115.5 74 n/a n/a

80th percentile

5.69 172.2 236 n/a n/a

n 8 8 8 n/a n/a

20th percentile

5.16 83.6 55.2 n/a n/a

n/a = not enough samples for valid statistics


Page 12-44

Table 12-18 Groundwater Physical Parameer Summary Results – Bulimba Formation Aquifer



G1, G2, G5, G6, G7, G8, G9, G10, G11, C1 (shallow), C2 (shallow), C3 (shallow)

minimum 4.8 27 5.5 1.63 53

maximum 5.88 185 470 4.32 256

mean 5.4 58.8 53 2.43 211

median 5.4 37 27 2.09 233

80th percentile

5.58 71.6 80 2.986 251

n 32 27 32 7 7

20th percentile

5.2 34.2 16 1.72

215


Table 12-19 Groundwater Physical Parameter Summary Results – Rolling Downs Siltstone Aquifer



C1, C2, C3 minimum 4.8 40 5 n/a n/a

maximum 6.22 106 620 n/a n/a

mean 5.65 74 218 n/a n/a

median 5.62 79 110 n/a n/a

80th percentile

5.92 87 519 n/a n/a

n 14 8 14 n/a n/a

20th percentile

5.46 55.8 42.6 n/a n/a


12.7.3.2 Metals

Monitoring data for selected metals has been obtained, and is summarised in Table 12-20, Table 12-21 Table 12-22 and Table 12-23 for all bores and the three aquifer groupings.

Dissolved metals values are very low across almost all bores in all aquifers, when compared with the AWQG trigger values. One exception is dissolved copper, which is elevated across all aquifers and has a maximum of 0.975 mg/L (compared to 0.0014 mg/L per the AWQG). Values of copper appear highest in the Rolling Downs Siltstone aquifer. The other exception is dissolved zinc, which is which is elevated across all aquifers and has a maximum of 1.17 mg/L (compared to 0.008 mg/L per the AWQG). Values of zinc appear highest in the Rolling Downs Siltstone aquifer. It is considered that these values of metals reflect the geology of the site.


Page 12-45

Table 12-20 Groundwater Dissolved Metals Summary Results – All Bores

Bores Statistical Element Al (mg/L) As (mg/L) Cd (mg/L) Cr (mg/L) Cu (mg/L) Fe (mg/L) Pb (mg/L) Mn (mg/L) Hg (mg/L) Ni (mg/L) Zn (mg/L)

All Bores minimum 0.0050 0.0010 n/a 0.0010 0.0010 0.0100 0.0010 0.0010 n/a 0.0010 0.0080

maximum 0.1230 0.0020 n/a 0.0020 0.8940 2.5500 0.0020 0.1770 n/a 0.0240 1.1700

mean 0.0240 0.0013 n/a 0.0013 0.0535 0.3502 0.0012 0.0266 n/a 0.0048 0.0965

median 0.0160 0.0010 n/a 0.0010 0.0070 0.1020 0.0010 0.0080 n/a 0.0020 0.0430

80th percentile 0.0276 0.0014 n/a 0.0016 0.0410 0.4860 0.0012 0.0192 n/a 0.0070 0.0908

n 54 21 14 38 52 46 36 54 54 41 52

20th percentile 0.0098 0.0010 n/a 0.0010 0.0020 0.0210 0.0010 0.0024 n/a 0.0010 0.0180

n/a = results all below the detection limit, or not enough results for valid statistics

Table 12-21 Groundwater Dissolved Metals Summary Results – Bulimba Formation (Namaleta Creek) Aquifer


Al (mg/L)

As (mg/L)

Cd (mg/L)

Cr (mg/L)

Cu (mg/L)

Fe (mg/L)

Pb (mg/L)

Mn (mg/L)

Hg (mg/L)

Ni (mg/L)

Zn (mg/L)

G3, G4, G12, G13, G14

minimum 0.006 0.001 n/a n/a 0.002 0.011 n/a 0.002 n/a 0.001 0.017

maximum 0.033 0.002 n/a n/a 0.014 0.975 n/a 0.167 n/a 0.004 0.069

mean 0.021 0.0015 n/a n/a 0.0055 0.268 n/a 0.051 n/a 0.0023 0.036

median 0.0215 0.0015 n/a n/a 0.0035 0.079 n/a 0.0295 n/a 0.002 0.029

80th percentile 0.027 0.0018 n/a n/a 0.0088 0.443 n/a 0.09 n/a 0.003 0.0466

n 8 5 8 5 8 8 7 8 8 8 8

20th percentile 0.0170 0.0012 n/a n/a 0.0020 0.0210 n/a 0.0056 n/a 0.0010 0.0268



Page 12-46

Table 12-22 Groundwater Dissolved Metals Summary Results – Bulimba Formation Aquifer

Bores Statistical Element Al (mg/L)

As (mg/L)

Cd (mg/L)

Cr (mg/L)

Cu (mg/L)

Fe (mg/L)

Pb (mg/L)

Mn (mg/L)

Hg (mg/L)

Ni (mg/L)

Zn (mg/L)

G1, G2, G5, G6, G7, G8, G9, G10, G11, C1 (shallow), C2 (shallow),

minimum 0.005 n/a n/a n/a 0.001 0.01 n/a 0.001 n/a 0.001 0.008

maximum 0.08 0.001 n/a 0.002 0.894 2.55 0.002 0.032 n/a 0.024 0.165

mean 0.0177 n/a n/a n/a 0.0496 0.3879 n/a 0.0089 n/a 0.0061 0.0442

median 0.014 n/a n/a n/a 0.004 0.1065 n/a 0.007 n/a 0.002 0.029

80th percentile 0.0184 n/a n/a n/a 0.0282 0.4416 n/a 0.0148 n/a 0.0104 0.0686

n 32 8 6 22 30 27 18 32 32 21 30



Table 12-23 Groundwater Dissolved Metals Summary Results – Rolling Downs Siltstone Aquifer

Bores Statistical Element Al (mg/L) As (mg/L) Cd (mg/L) Cr (mg/L) Cu (mg/L) Fe (mg/L) Pb (mg/L) Mn (mg/L) Hg (mg/L) Ni (mg/L) Zn (mg/L)

C1, C2, C3 minimum 0.006 n/a n/a n/a 0.001 0.011 n/a 0.002 n/a 0.001 0.013

maximum 0.123 0.001 n/a 0.001 0.762 0.55 0.001 0.177 n/a 0.008 1.17

mean 0.0412 n/a n/a n/a 0.0905 0.2980 n/a 0.0550 n/a 0.0046 0.2628

median 0.0285 n/a n/a n/a 0.04 0.42 n/a 0.012 n/a 0.0055 0.107


n 14 8 6 11 14 11 11 14 14 13 14




Page 12-47

12.7.3.3 Nutrients

Monitoring data for total nitrogen and total phosphorus has been obtained, and is summarised Table 12-24, Table 12-25, Table 12-26 and Table 12-27 for the three aquifer groupings. Nutrient values (TN, TP) are low across all bores, with no appreciable difference between aquifers. There are limited test results for nutrients, and additional sampling over time may lead to discernible differences being noted.

Table 12-24 Groundwater Nutrient Summary Results – All Bores

Bores Statistical Element Nitrogen (total) (mg/L N)

Phosphorus (total) (mg/L P)

G3, G4, G12, G13, G14 minimum 0.0500 0.0100

maximum 1.9000 0.3100

mean 0.2304 0.0727

median 0.1600 0.0400


n 54 54

Table 12-25 Groundwater Nutrient Summary Results – Bulimba Formation (Namaleta Creek) Aquifer



G3, G4, G12, G13, G14 minimum 0.06 0.02

maximum 1.9 0.24

mean 0.415 0.095

median 0.18 0.075


n 8 8

Table 12-26 Groundwater Nutrient Summary Results – Bulimba Formation Aquifer



G1, G2, G5, G6, G7, G8, G9, G10, G11, C1 (shallow), C2 (shallow), C3 (shallow)

minimum 0.05 0.01

maximum 0.84 0.31

mean 0.1947 0.0643

median 0.105 0.03


n 32 32

Table 12-27 Groundwater Nutrient Summary Results – Rolling Downs Siltstone Aquifer



C1, C2, C3 minimum 0.08 0.01

maximum 0.39 0.3

mean 0.1936 0.0710

median 0.19 0.04


n 14 14

12.8 Potential Impacts, Emissions and Releases

The potential impacts to surface water quality are:


Page 12-48

low risk of uncontrolled release of water with high sediment loads from bauxite mining areas (not

expected as mining areas will be internally draining)

stormwater runoff with sediment from haul roads, including the Namaleta Creek crossing area

sedimentation of waterways during construction and vegetation clearing

uncontrolled release of potentially hydrocarbon and chemical contaminated water from

infrastructure areas.

The potential impacts to groundwater quality are:

localised impacts to groundwater quality hydraulically down-gradient from the landfill, treated

effluent irrigation area and bio-remediation pad through seepage


infrastructure areas

possible saline water ingress resulting from extraction of water from kaolin storages, borefield

pumping for Project water supply and mining of pits.

Chapter 13 describes potential impacts to surface water hydrology and groundwater hydrogeology.

12.9 Mitigation and Management Measures

Water management for the Project is described in Chapter 6 and the management measures relevant to mitigating potential impacts described in Section 12.8 and achieving the environmental objectives and performance outcomes described in Section 12.2 are described below.

Kaolin mine water management is undertaken in accordance with the conditions of the existing EA and the kaolin mine’s Plan of Operations. Kaolin mine water management has been incorporated in the EM Plan (Appendix 13) and the Surface Water and Groundwater Monitoring Plan (Appendix 15).

The proposed groundwater and surface water monitoring plan is described in Section 12.10.

12.9.1 Mine Pits

During operational periods, rainfall runoff entering the pit will be drained internally and contained within the pit, to be lost as evaporation and as recharge to local aquifers. Mine pits are shown in Chapter 5, Figure 5-14.

Due to the nature of bauxite mining (shallow pits to approximately 6 m depth, located at the top of localised catchments and hydrogeology of pit areas allowing seepage from pits) there is no requirement for external storage and release of water captured within pits.

Surface water runoff does not occur as long as the mine floor lies below the surrounding terrain. Stormwater drains through the groundwater system. This process is enhanced by deep ripping of the mine floor, which will occur prior to the wet season in most bauxite mining areas. Placement of soil and bauxite waste on the mine floor will be even and parallel to the mine floor topography, which should be closely parallel to the original land surface. The edges of mining areas will be battered down to a 5:1 slope and re-vegetated as for the mine floor. Erosion within mined areas is negligible due to the generally flat or gently sloping terrain.

To prevent surface water runoff from mining areas, the following measures will be adopted for erosion and sediment management:

Clearing and mining will not be carried out in areas of steep drop-off slope from the general terrain

– expected generally to be within 100 m of natural waterways and swamps.


Page 12-49

Ripping will be conducted along contour lines, or offset to direct water away from valleys, using

Keyline principles (i.e. management of the topography to control runoff).

Should a low area be (erroneously) mined on the edge of a mining area, with potential to allow out-

flow of stormwater, earth bunds and silt traps will be constructed, as well as strategic contour banks

on the mine floor to direct flow away from the area. All structures would be stabilized with

establishment of grass cover, trees and shrubs.

Resource surveys have been undertaken to inform the location of economic bauxite resources. This has resulted in accurate delineation of pits areas which avoid:

buffer zones around wetland and watercourses (refer to Chapter 15)

low lying areas with the potential to require erosion and sediment control measures to prevent

outflow from pits

unnecessary clearance of vegetation in areas that will not be mined.

Land clearing in advance of mining will be undertaken in the dry season. Gulf Alumina will undertake annual vegetation clearing, windrowing and burning in advance of proposed mining. Mining will generally occur in the same year (i.e. during the dry season) and therefore there is limited potential for erosion following clearing activities. Following clearing and prior to mining, these areas will be stabilised by allowing regrowth of grasses and shrubs and to maintain viability of the soil for plant growth. Where there is a risk of increased sedimentation from areas cleared of deep rooted vegetation, erosion and sediment control measures (refer to Section 12.9.4) will be installed.

12.9.1.1 Mine Site Sediment Management

The topography of the Project area is shown in Chapter 10 and is generally low lying and flat with topography rising towards a ridge where bauxite deposits are located. The Project mining leases are at around 5 – 20 mAHD elevation where bauxite deposits occur, 3 - 8 mAHD at the Port infrastructure area and lower in creek and wetland areas. The bauxite pits are located at the top of the local catchments and hence external catchments reporting to the pits will be minimal.

Under the proposed mining approach, there will be no sediment runoff from mining areas to surrounding land and waters as runoff will be located within the pits. Sediment ponds receiving drainage from the disturbed mining areas will be managed in pit. Design will be carried out in accordance with best practice approaches and as part of an Erosion and Sediment Control Plan (ESCP). The ESCP will be developed in line with the IECA Manual which provides guidelines for erosion control on site, sediment pond design and construction, and their operation and maintenance.

The design and management details for in pit sediment ponds will be determined as an ongoing operational activity. However, preliminary estimates have been made for the sediment runoff volumes, and indicative geometric requirements for the expected sediment ponds within each pit. As described in Appendix 4, pond sizing was completed using the CALM approach. The approach depends on the erodibility of soil, peak runoff discharge and the volume of sediment likely to enter the structure. The basin surface area is determined as a function of the inflow rate and the target particle settling velocity.

The estimate catchments areas for each pit, sediment runoff volume and in-pit pond sizes and are provided in Table 12-28. Nominal sediment basin volumes range between 400 m3 and 88100 m3 with minimum storage depth requirements of between 2.0 and 2.3 m. This depth requirement could be reduced further, subject to pond management practices, with regular scouring and dredging to maximise containment volumes. The nominal in-pit pond size is approximately 0.5% of the pit catchment area for each pit. It is clear that in-pit sediment ponds will occupy a minor portion of each pit and that the pit itself will act to capture any runoff should the sediment basins overtop.


Page 12-50

Table 12-28 Catchments Areas, Sediment Runoff and Pond/Dam Sizing

Pit Local Catchment Area (ha)

Sediment Volume (m3/y)

Nominal Pond Area (m2)

Minimum Storage Depth (m)

Pond Volume (m3)

Pit 1 78.1 5639 3300 2.1 7055

Pit 2 31.0 2238 1400 2.0 2855

Pit 3 296.0 21337 25000 2.1 53436

Pit 4 7.4 536 350 2.0 693

Pit 5 27.8 2007 1200 2.1 2527

Pit 6 4.4 318 200 2.0 407

Pit 7 43.6 3145 1900 2.1 3971

Pit 8 18.2 1314 800 2.1 1663

Pit 9 17.3 1249 800 2.0 1604

Pit 10 8.9 645 400 2.1 820

Pit 11 160.0 11553 6800 2.2 15254

Pit 12 369.0 26644 38000 2.3 88131

Pit 13 65.6 4737 2800 2.1 5943

Pit 14 83.6 6036 3600 2.1 7593

Pit 15 219.0 15813 12000 2.1 25616

12.9.1.2 Mine Site Sediment Pond Management

The in-pit sediment ponds will be used opportunistically to meet local demand for water (e.g. dust suppression) thereby reducing the need for supply from other sources (e.g. shallow aquifer bores). For the dual purposes of containing sediment on site for controlled disposal and for providing low quality water supply, sediment and erosion control measures will include:

regular inspection of the in-pit sediment storage structures conducted at the conclusion of the wet

season (typically in April-May).

monitoring of sediment deposition volumes and identification if a clean out is required to provide

sufficient storage for sediment loading in runoff and improve storage availability where sediment in-

pit ponds are in use for dust suppression.

Clean out will be completed immediately prior to the wet season, and sediment will be disposed of in a location where erosion will be limited or contained (e.g. mining areas undergoing rehabilitation), and will not contribute to sediment loads reporting to other control structures.

12.9.2 Port Infrastructure Area

12.9.2.1 Design and Management

A new sediment pond will be required at the Port infrastructure area, in addition to the existing sediment pond (which will be retained) to capture runoff from disturbance areas, including the bauxite stockpile, paved areas, workshops and haul roads. The proposed and existing sediment ponds are shown in Figure 12-13, which also shows runoff flow paths and drainage control structures.


Page 12-51

The existing sediment pond will capture runoff from a smaller area than the area for kaolin mine activities only. The proposed sediment pond will absorb some of the catchment of the existing sediment pond and capture runoff from the bauxite stockpile area.

Port sediment pond conceptual engineering design has been undertaken to understand the performance of the dams in managing sediment in Port infrastructure area. The key issues in the design of the sediment ponds are:

pond catchment size and size of ponds

natural of material resulting in sediment (i.e. particle size, clay content) within each catchment

engineering design standards for sediment ponds

distinction between operational periods (i.e. April to December) and non-operational periods (wet

season shut down January to March) for sediment management.

Port sediment pond design and management is described in Chapter 6, Section 6.4.3.

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Revision: R1



Port Area Sediment Pondsand Drainage

0 50 100 150 200 250Meters


No warranty is given in relation to the data (including accuracy, reliability, completeness or suitability) and accept no liability (including without limitation, liability in negligence) for any loss, damage or costs (including consequential damage) relating to any use of or reliance upon the data. Data must not be used for direct marketing or be used in breach of privacy laws.Imagery supplied by Gulf Alumina (2014). Tenures © Geos Mining (2015). State Boundaries and Towns © Geoscience Australia (2006).

±

*Port/Wharf infrastructure are indicative layouts only and adapted from plans created by Sedgman Ltd.Pond catchments and drainage are indicative and based on plans created by Sedgman Ltd.


Page 12-53

12.9.2.2 Release Monitoring

Port sediment pond release monitoring, including contaminant release limits, are described in Chapter 17 as release limits are based on estuarine water quality data from the Skardon River, as presented in Chapter 17.

12.9.3 Effluent Irrigation Area

Chapter 8 describes treated effluent management, including release conditions to minimise the potential for impacts to land and waters. Chapter 8 describes monitoring of groundwater up gradient and down gradient of the treated effluent irrigation area, including monitoring locations, frequency, parameters and contaminant limits.

12.9.4 Erosion and Sediment Control

Other than the Port infrastructure area and mining areas, erosion and sediment control measures will be implemented at:

construction areas

permanent haul roads

haul road crossing of Namaleta Creek and other drainage features

12.9.4.1 Erosion and Sediment Control Plan

An erosion and sediment control plan (ESCP) will be developed for the Project prior to commencement of construction and mining activities and will cover all aspects of the Project including clearing, construction, operations, rehabilitation and decommissioning. The ESCP will be approved by a suitably qualified person2 (such as a Certified Professional in Erosion and Sediment Control).

An ESCP will be developed in accordance with the:

recommended guidelines of the International Erosion Control Association (IECA) Manual (IECA,

2008)

Soil Erosion and Sediment Control-Engineering Guidelines for Queensland Construction Sites

(Witheridge and Walker, 1996)

The most critical aspects of the ESCP are set out below.

An assessment of erosion risk will be undertaken for different parts of the Project area.

Soil types will be assessed (refer Chapter 10), including identification of erosion potential.

Soil will be managed in accordance with the measures described in Chapter 10 for soil stripping,

handling, stockpiling and testing.

Development of the ESCP will be integrated into the mine planning process.

Sensitive areas (e.g. buffer zones around watercourses and wetlands) that may require specific

measures to prevent sedimentation will be identified.

The period of maximum disturbance will be planned to occur in the dry season.

Construction activities and land clearing will be undertaken in the dry season.

The extent and duration of disturbance (topsoil and subsoil exposure) will be minimised.

2 For example, an appropriately qualified person as defined in Stormwater guideline – Environmentally relevant activities (EHP, 2014)


Page 12-54

Boundaries of areas to be cleared will be delineated and clearing will be authorised by use of a

‘permit to clear’ system.

Grubbing out and removal of ground cover will be carried out as close to the time of mining or

earthworks as possible.

Stabilisation of areas cleared in advance of mining will occur through allowing regrowth of grasses

and shrubs.

Stormwater runoff from external or undisturbed catchments will be diverted around or away from

infrastructure construction areas.

Uncontaminated stormwater run-off will be diverted around areas disturbed by Port infrastructure

area activities or where contaminants or wastes are stored or handled.

All drainage structures and sediment controls will have design specifications appropriate to the

rainfall regime and design life.

Erosion controls will be used to minimise sediment generation and transport.

Sediment controls will be used to treat run-off from disturbed areas prior to leaving the site.

Sediment controls will be located as close to the source as possible.

Erosion and sediment control structures will be installed as required, prior to disturbance in that

area of site.

Disturbed areas will be stabilised as soon as possible (progressively rehabilitated).

Control structures will be inspected regularly.

Details of the rehabilitation of the site, including final landform design is provided in Chapter 7. Rehabilitated landforms will be designed to minimise slope angle and length. Erosion loss decreases exponentially with percentage ground cover and is greatly reduced when cover exceeds 50%. For long-term stabilisation in tropical climates, IECA (2008) recommends a minimum ground cover of 80% which will considered as the target for this Project. Vegetation establishment will be required for long-term soil stabilisation. All revegetated areas will be monitored to ensure the desired ground cover is achieved and further seeding or planting is conducted in areas that do not meet the desired target.

Chapter 15 and Chapter 16 described the proposed vegetation buffer zones around wetlands, watercourses and drainage features. These buffer zones will act to reduce potential impacts from sediment laden runoff.

Erosion mitigation measures specifically relevant to waterways include the following:

Where earthworks are carried out in proximity to a watercourse, disturbance will be stabilised.

Felled timber will be removed from the area and stockpiled away from the watercourse.

Where required temporary controls will be installed along cleared slopes approaching watercourses,

to divert dirty water away from the watercourse.

Clean rock and culverts will be used for temporary watercourse crossings

Water discharged to a waterway will meet Project water quality objectives.

The ESCP may include measures such as:

velocity slowing methods including rock and log placement in cleared areas

restriction of land disturbance

scour protection design methods for drainage

rehabilitation practices to limit erosion.


Page 12-55

The ESCP will be implemented for construction and throughout operations. Drainage and erosion control will be implemented as a part of operational activities using measures such as erosion control blankets, check dams, filter fences and rock mattresses.

Monitoring of erosion and sediment control structures will be carried out both pre- and post-wet season and following any significant events. Monitoring may be done using visual methods (such as those for recording erosion features) and/or more quantitative methods such as those using erosion monitoring pins, or measuring sediment loads from monitored catchments.

Monitoring of erosion and sediment controls may include:

visual inspections undertaken regularly and following significant rainfall e.g. 20 mm in 24 hours

daily monitoring of weather predictions to manage clearing and construction activities.

completion of site inspection checklist

supervisors to visually monitor all operations and identify where correct procedures are not being

followed

contractors to monitor works and should they become aware of improper management practices, to

report the issue to their supervisor.

site supervisors will be responsible for modifying or stopping non-conforming management

practices until corrective actions are determined

corrective and preventive actions to be implemented and monitored visually on site to ensure they

are effective.

12.9.4.2 Permanent Haul Roads

Permanent haul roads (i.e. the main haul road connecting the Port area to the mining areas to the south) will be designed in consideration of the Department of Transport and Main Road’s (TMR’s) Road Drainage Manual (TMR, 2015). This provides technical guidance on road drainage, erosion, environmental and sediment control.

12.9.5 Namaleta Creek Crossing

12.9.5.1 Location

The location of the proposed crossing of Namaleta Creek is shown in Figure 12-14. This is the same location as the existing crossing.

12.9.5.2 Existing Crossing

The existing crossing of Namaleta Creek crossing consists of an earthen crossing (10 – 15 m wide), where two cylindrical pipes connect the upstream and downstream reaches of Namaleta Creek. These existing pipe culverts may be impacting flows and fish passage. The section of road currently crossing the south-western flood plain of Namaleta Creek (refer to Figure 12-14) is restricting normal flow during the height of the wet season.

12.9.5.3 Crossing Design

The crossing will be upgraded to support haul truck movements between mining areas to the south of Namaleta Creek and the Port. The corridor associated with the proposed upgrade of the crossing will be 25 m wide, except for the section requiring culverts, which may have a construction width of 60 m (culvert width approximately 40 m). The design of the crossing will be in accordance with the Department of Agriculture and Fisheries Code for Self-assessable Development – Minor Waterway Barrier Works, Part 3 Culvert Crossings, Code Number: WWBW01 April 2013 (the Code). This Code is


Page 12-56

designed to minimise impacts to fish passage. In this respect the upgraded crossing will result in the hydrology of the area more closely resembling its pre-disturbance condition.

Conceptual design schematics for the Namaleta Crossing are presented Chapter 6:

Schematic 1 shows the crossing layout, including chainage from the northern side of the crossing

(i.e. near the kaolin pits) on the left (chainage = 0 to the end of the floodplain to the south (chainage

494).

Schematic 2 shows the longitudinal plan with chainage 0 on the left and chainage 300 on the right,

which due to the scale, condenses the width of the culverts. As can be seem in Schematic 2, the

crossing height is at its maximum in the centre of the channel crossing, allowing for control of runoff

control away from the Creek.

Schematic 3 continues from the previous schematic and shows the longitudinal plan with chainage

300 on the left and chainage 494 on the right.

Schematic 4 shows a cross section through the portion of the crossing with the main flow path

channel of Namaleta Creek.

Chapter 14 describes the crossing design for the purpose of flood protection. This flood protection has been adopted in the conceptual engineering schematics shown above. A schematic cross-section of the Namaleta Creek crossing, for the purposes of modelling flood protection, is shown in Figure 12-15. The culverts and deck level of the crossing were sized for a 1:50 year AEP design flood standard. The flood model in Chapter 14 also demonstrates that the haul road crossing will meet a design flood level of 1:100 years (i.e. the haul road crossing will not be overtopped by a 1:100 year flood).. Figure 12-15 shows the preliminary sizings of the culvert groupings proposed to convey water through the haul crossing embankment, as applied in the model. Note that the culverts are distorted by the aspect ratio of the cross-section.

Namaleta CreekCrossing

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1.51.5

0.5

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0

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2.52.5NAMALETA CREEK

Pit #14

609400 609600 60980086

8580

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8686

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Figure12-14

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Namaleta Creek Crossing Location

0 50 100 150 200Meters


!

!

!

!

Queensland

CAIRNS

BRISBANE

TOWNSVILLE

ROCKHAMPTON

±

No warranty is given in relation to the data (including accuracy, reliability, completeness or suitability) and accept no liability (including without limitation, liability in negligence) for any loss, damage or costs (including consequential damage) relating to any use of or reliance upon the data. Data must not be used for direct marketing or be used in breach of privacy laws. Tenures © Geos Mining (2015). State Boundaries and Towns © Geoscience Australia (2006). Watercourses © Geoscience Australia. Imagery sourced from Gulf Alumina. Waterways for Waterway Barrierworks © State of Queensland (Department of Agriculture and Fisheries) 2015.


Mining Lease BoundariesWatercoursesExisting Disturbance FootprintProject Footprint

Haul RoadCrossing

Elevation Contours (0.5m)Queensland Waterways forWaterway Barrier WorksRisk of Impact

2 - Moderate (Streams)



Page 12-58

Figure 12-15 Namaleta Creek Crossing – Downstream View

Preliminary sizing of the culvert groups and bridge deck level required at the crossing was carried out with reference to the guidelines and recommendations of the Road Drainage Manual, Department of Transport and Main Roads, July 2015 (TMR-RDM).

Detailed design will be carried out in compliance with the TMR-RDM and with:

Roads in the Wet Tropics Manual, Transport and Main Roads, 1998)

design detail requirements of the Code for Self-Assessable Development; Minor Waterway Barrier

Works Part 3: Culvert Crossings, Code number: WWWBW01 (April 2013), Department of Agriculture,

Fisheries and Forestry (DAFF).

The following specific conditions are noted from the Code for addressing moderate impact waterways (applicable to Namaleta Creek):

Works must commence and finish within a maximum time of 360 calendar days and instream

sediment and instream silt control measures associated with the works must be removed within this

period.

The crossing must have a minimum (combined) culvert aperture width of 2.4 m or span 100% of the

main channel width.

All new or replacement culvert cells must be installed at or below bed level.

The internal roof of the culverts must be >300 mm above ‘the commence to flow’ water level.

Where the cell is installed at less than 300 mm below bed level (potentially the case for the

Namaleta Crossing), the culvert floor must be roughened throughout to approximately simulate

natural bed conditions.

The culvert must be installed at no steeper gradient than the waterway bed gradient.

Apron and stream bed scour protection must be provided in line with the design requirements of

the Code.

Based on conceptual design of the crossing presented in Chapter 6, it is expected that the Code requirements can be met for the Namaleta crossing design.

12.9.5.4 Crossing Drainage

Drainage from road surface of the crossing will be directed to the ends away from the Creek, by peaking the height of the crossing at its centre and raising the entire crossing above the elevation of the surrounding topography. Thus stormwater runoff will drain to the entry points of the crossing


Page 12-59

approximately 50 m to 100 m from the Creek bank. Silt traps will be installed at the end of the drains and over flow directed into contour drains. On the south-west side this water will flow into natural vegetation while on the north-east side water will be directed into kaolin mine revegetation areas, or kaolin mine water storages.

12.9.5.5 Crossing Construction and Rehabilitation

To prevent any instream impacts including sedimentation to Namaleta Creek and the mapped HES wetland during the construction of haul road crossing, construction activities will be scheduled for the dry season, when the potential for impact is minimised due to low or no flow conditions when temporary impoundments are not expected to be required when working within the in-stream environments. This strategy is also part of avoiding disturbance of acid sulphate soil, the management of which is described in Chapter 10.

With construction of the proposed crossing within a single dry season, temporary changes to the drainage and flow regimes will be avoided and Creek flow will be improved from the current situation in the following wet season. Construction work within Namaleta Creek will ensure that all surfaces are adequately stabilised following the completion of the haul road crossing. This will include revegetation of exposed embankment areas and mulching if necessary until stream banks have stabilised.

The crossing will be constructed with ironstone material from the borrow pits over a claystone core, using material from the kaolin claystone overburden stockpile. The claystone core material will not be exposed to erosion, with batter protection being provided through concrete, rock and / or geofabric, and material encased by ironstone and waste bauxite material.

12.9.6 Crossings of other Drainage Features

The haul road will cross a drainage feature between Pits 14 and 15 to the south of Namaleta Creek (referred to as Tributary 1), as shown in Figure 12-16. This drainage feature is mapped as moderate risk for waterway barrier works. Mining is not scheduled south of this crossing (i.e. when the crossing will be required) until Year 7 of mining. The design of the crossing will be in accordance with the Department of Agriculture and Fisheries Code for Self-assessable Development – Minor Waterway Barrier Works, Part 4 Bed Level Crossings, Code Number: WWBW01 April 2013.

The conceptual design of the crossing is shown in the schematics in Chapter 6:

Schematic 5 shows the crossing layout, including chainage from the northern side of the crossing

(chainage 0) to the southern side (chainage 240).

Schematic 6 shows the longitudinal plan with chainage 0 on the left and chainage 240 on the right.

All works required within the drainage feature will ensure that all surfaces are adequately stabilised following the completion of the haul road construction. This will include revegetation of exposed embankment areas and temporary erosion and sediment control until construction is completed or drainage feature banks have been stabilised.

The following specific conditions are noted from the Code for addressing moderate impact waterways (applicable to Tributary 1 crossing):

The bed level crossing must be no greater than 15 metres wide in an upstream/downstream direction (not including stream bed scour protection).

New bed level crossings must be aligned perpendicular (within 10°) to the water flow.

Where the bed level crossing is to be constructed from rocks, use clean rocks (minimal fine material) that are an equivalent or larger size than the natural bed material at the site, and at least 50 mm diameter.


Page 12-60

Stream bed scour protection must be provided in line with the design requirements of the Code.

Works must commence and finish within a maximum time of 360 calendar days and instream sediment and silt control measures associated with the works must be removed within this period.

The lowest point of the bed level crossing must be installed at the level of the lowest point of the natural stream bed (pre-construction), within the footprint of the proposed crossing.

There must be a height difference of at least 100 mm from the lowest point of the crossing to the edges of the low flow section of the crossing.

If the crossing is constructed from concrete or introduced rock, the level of the remainder of the crossing must be no higher than the lowest point of the natural stream bed outside of the low flow channel.

If the crossing is constructed from the natural bed material, the level of the remainder of the crossing must be no higher than the highest point of the natural stream bed outside the low flow channel.

Based on conceptual design of the crossing presented in the above schematics, it is expected that the Code requirements can be met for the Tributary 1 crossing design.

Drainage FeatureCrossing

9

8.5

8

7.576.5

8.5

8 9

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8

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Pit #14

Pit #15

Pit #15

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Figure12-16

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Haul Road Crossing ofDrainage Features

0 50 100 150 200Meters


!

!

!

!

Queensland

CAIRNS

BRISBANE

TOWNSVILLE

ROCKHAMPTON

±

No warranty is given in relation to the data (including accuracy, reliability, completeness or suitability) and accept no liability (including without limitation, liability in negligence) for any loss, damage or costs (including consequential damage) relating to any use of or reliance upon the data. Data must not be used for direct marketing or be used in breach of privacy laws. Tenures © Geos Mining (2015). State Boundaries and Towns © Geoscience Australia (2006). Watercourses © Geoscience Australia. Imagery sourced from Gulf Alumina. Waterways for Waterway Barrierworks © State of Queensland (Department of Agriculture and Fisheries) 2015.


Mining Lease BoundariesWatercoursesExisting Disturbance FootprintProject Footprint

Haul RoadCrossing

Elevation Contours (0.5m)Queensland Waterways forWaterway Barrier WorksRisk of Impact

2 - Moderate (Streams)



Page 12-62

12.10 Surface Water and Groundwater Monitoring Plan

A baseline monitoring programme, as described in Section 12.6 (surface water) and Section 12.7 (groundwater) has been established by Gulf to provide data for surface water quality, surface water depth, groundwater quality and groundwater level. This data has been used to establish baseline conditions and understand natural variations. These sites will continue to be monitored to detect potential Project impacts during construction and operations. The intention is to expand the monitoring network prior to construction and operations, as described below. The following areas are currently monitored in line with the EA requirements for the kaolin mine:

receiving waters affected by the release of process water and/or stormwater potentially

contaminated by former kaolin mining activities (approximately 100m upstream and 100m to 500m

downstream of the existing water storages)

contaminants from discharge points from kaolin mine water storages (discharge points from the

Raw Water Pit, western sump of Fluvial Pit, south side of Namaleta Creek and stormwater drains on

the bank of the Skardon River at the Port)

effluent released from the treatment plant at the camp to be released to the effluent irrigation area

groundwater potentially affected by former kaolin mining activities.

The proposed Surface Water and Groundwater Monitoring Plan is provided in Appendix 15. This plan describes:

rationale for selection of parameters to be monitored

proposed locations for monitoring and function of each monitoring location

proposed frequency of monitoring

additional analysis of existing water quality data (refer to Section 12.6.3 and Section 12.7.3)

selection of reference sites

proposed monitoring to establish local water quality objectives (baseline conditions) prior to mining

activities impacting particular waters, where local water quality objectives do not currently exist

monitoring to be undertaken as part of a Receiving Environment Monitoring Program (REMP)

monitoring of particular potential impacts:

Namaleta Creek and Tributary 1 construction crossing

releases from kaolin mine water storages

salinity levels in estuarine / freshwater zones of Namaleta Creek

potential groundwater contamination at the Port area from the landfill, bioremediation pad and

from hydrocarbon management

potential groundwater contamination at the treated effluent irrigation area

criteria for determining whether the Project has resulted in a ‘change’ in water quality

management and mitigation measures for Project impacts identified through monitoring

Information from the Surface Water and Groundwater Monitoring Plan is Appendix 15 is summarised below.


Page 12-63

12.10.1 Surface Water Monitoring Locations

Monitoring of surface water has been carried out at several sites on Namaleta Creek, Skardon River, Lunette Swamp and Bigfoot Swamp, as described in Section 12.6.

The existing and proposed surface water monitoring locations are described in Appendix 15 and shown in Figure 12-17.

The current EA specifies surface water monitoring for the decommissioned kaolin mine. This monitoring will continue during the Project and will provide information to understand potential impacts of the kaolin mine and the Project.

The proposed monitoring locations and function of each location are described in Table 12-29. Surface water monitoring will be for water quality, water levels in swamps and in receiving waterways, and for flows in the receiving waterway.

The catchments and drainages surrounding the Project area are small and comprise a mix of freshwater and estuarine water. The design of the monitoring programme involves three distinct catchment zones:

Namaleta Creek catchment, including Tributary 1, comprising freshwater and estuarine zones..

Skardon River supratidal wetland

Drainages and wetlands downstream of the central mining areas including Lunette Swamp and

Bigfoot Swamp.

Monitoring of the marine environment in the Skardon River is described in Chapter 17. Table 12-29 does not include Port sediment pond release monitoring sites (S13 and S14) or marine monitoring sites in the Skardon River as these are described in Chapter 17.

!(

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ML 6025

ML 40082

ML 40069

SKARDON RIVER

NAMALETA CREEK

S15

S16

S7

S10

S11

S12

S18

S19

S22S20

605000 610000 61500086

8500

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8685

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8690

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8690

000

8695

000

8695

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8700

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8700

000

Figure12-17

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Existing and Proposed SurfaceWater Monitoring Locations



!

!

!

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BRISBANE

TOWNSVILLE

ROCKHAMPTON

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!( Port of Skardon RiverPort Sediment PondWatercourses

Surface Water Monitoring Locations!> Existing!> Proposed

!>

!>

!>

!>

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S3

S2

S1

S4

S5

S6

S8

S9

S21

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S13

S14S17

1:30,000

1:30,000


Page 12-65

Table 12-29 Existing and Proposed Surface Water Monitoring Network

Monitoring Point

Name per Current EA#

Location Details Site Function – Kaolin Mine

Site Function – Bauxite Project Depth Logger Installed

Easting (m)

Northing (m)

Namaleta Creek

S1 n/a Namaleta Creek – upstream of bauxite mining

Reference Site Reference site – quality, depth and flows.

Yes 610491 8685825

S2 Namaleta Creek Upstream

100 m upstream of existing crossing

Reference site Reference site - downstream of Pits 12 and 14 during mining. Prior to mining, upstream of kaolin mine and hence provides baseline data.

No 609949 8686287

S3 W1 Discharge (release) point from the Raw Water Pit

Compliance - end of pipe discharge monitoring. Compared with Namaleta Creek upstream site

Limited direct relevance for bauxite mine, may assist in differentiating between potential impacts of kaolin mine and bauxite mining.

No 609803 8686458

S4 n/a Raw Water Pit Monitor water quality of storages

Limited direct relevance for bauxite mine. Water quality will be used to assess if it is suitable for use in dust suppression, bauxite stockpile moisture content and washdowns

Yes 609937 8686458

S5 W6 Discharge (release) point from Western sump of current Fluvial Pit

Compliance - end of pipe discharge monitoring. Compared with Namaleta Creek upstream site

Limited direct relevance for bauxite mine, may assist in differentiating between potential impacts of kaolin mine and bauxite mining.

Yes 609409 8686750


Page 12-66

Monitoring Point




Easting (m)

Northing (m)

S6 Namaleta Creek: Downstream

Namaleta Creek: for an impacted site between 100 and 500 m downstream of kaolin mining area

Compliance site. Compared with Namaleta Creek upstream site

Compliance site downstream of Pits 12 and 14 during mining. Downstream of existing kaolin mine so provides baseline data for water quality potentially impacted by kaolin mine. Flows to be monitored.

No 609392 8686912

S7 n/a Namaleta Creek – downstream of Pits 14 and 15, crossover between freshwater and estuarine systems

n/a Reference site prior to mining for estuarine water. Compliance site for estuarine water once mining commences.

No 607021 8685776

S8 n/a Namaleta Creek immediately upstream of current crossing

Water quality upstream of crossing and near Raw Water Pit. Access easy and safe from crossing.

Compliance site downstream of Pits 12 and 14. Provides reasonable indication of baseline water quality in Namaleta Creek. Proposed for ongoing monitoring programme for quality and depth in case access restricted at other locations.

Yes 609654 8686412

S9 n/a Namaleta Creek immediately downstream of current crossing

Water quality downstream of crossing and near Raw Water Pit. Access easy and safe from crossing.

Compliance site downstream of Pits 12 and 14 and crossing. Provides reasonable indication of baseline water quality in Namaleta Creek. Baseline depth data unimpacted by crossing. Proposed for ongoing monitoring programme in case access restricted at other locations.

Yes 609644 8686416


Page 12-67

Monitoring Point




Easting (m)

Northing (m)

S20 n/a Namaleta Creek – downstream of Pit 14, crossover between freshwater and estuarine systems

n/a Reference site prior to mining for estuarine water. Compliance site for estuarine water once mining commences. Additional data on estuarine / freshwater zone at a point between S6 and S7.

No 608243 8686784

S21 n/a Tributary 1 – upstream of proposed crossing and all mining

n/a Reference site prior to and during mining. Upstream monitoring during construction crossing.

No 609494 8685155

S22 n/a Tributary 1 – immediately upstream of confluence with Namaleta Creek

n/a Reference site prior to mining. Downstream monitoring during construction crossing.

No 608085 8686580

Wetlands

S10 n/a Lunette Swamp n/a Water quality and depth. Reference site prior to mining. Compliance site once mining commences.

Yes 612039 8688649

S11 n/a Bigfoot Swamp n/a Water quality and depth. Reference site prior to mining. Compliance site once mining commences.

Yes 612860 8695847

S12 n/a Unnamed creek – downstream Lunette Swamp

n/a Downstream of Pits 3, 4, 5, 8, 9, 10, 11, 12, 13. Reference site prior to mining. Compliance site once mining commences.

No 611778 8690224

S18 n/a Skardon River n/a Reference site prior to mining. No 616935 8697561


Page 12-68

Monitoring Point




Easting (m)

Northing (m)

supratidal wetland Compliance site once mining commences.

S19 n/a Skardon River supratidal wetland

n/a Reference site prior to mining. Compliance site once mining commences.

No 615955 8695448

# The location specified for ongoing monitoring may differ to slightly to the location in the EA in order to provide an improved monitoring location that considers accessibility and

effectiveness in achieving the intended monitoring purpose.


Page 12-69

12.10.2 Surface Water Monitoring Frequency and Parameters

Appendix 15 describes the proposed parameters for monitoring and the frequency of monitoring for:

establishing local WQOs

a REMP

kaolin mine water storages releases

construction of crossings

Appendix 15 provides the proposed end of pipe contaminant release limits for the kaolin water storages.

The surface water samples will be analysed by a registered NATA accredited laboratory and sample collection and transportation will follow guidelines and protocols provided within the Monitoring and Sampling Manual 2009 (EHP, 2010).

The following information will be recorded for all water monitoring:

the date on which the sample was taken

the time at which the sample was taken

the monitoring point at which the sample was taken

the results of all monitoring and details of any exceedances of the conditions of the EA.

12.10.3 Receiving Environment Monitoring Programme

The Surface Water and Groundwater Monitoring Plan (Appendix 15) will commence prior to construction and operations and continue throughout the mine life. This Monitoring Plan will inform the requirements of a Receiving Environment Monitoring Program (REMP) to monitor, identify and describe any adverse impacts to surface water environmental values, quality and levels due to bauxite mining activity. The REMP will be informed by:

environmental values identified in Section 12.4 and Section 12.5

water quality objectives and indicators / parameters proposed for monitoring, including water

depth and Creek flows (Section 12.5)

location of monitoring sites, including reference sites and compliance / control sites (Table 12-29)

timing and frequency of sampling (Appendix 15)

Monitoring will involve a combination of (i) in situ measurements obtained using field instruments to monitor indicators such as turbidity, EC, DO and pH, and (ii) field sampling using manual grab sampling or auto-sampling with subsequent laboratory analysis.

Monitoring will be undertaken in accordance with the Monitoring and Sampling Manual (EHP, 2009). The REMP will define quality assurance / quality control (QA/QC) procedures for all aspects of monitoring. Data analysis methods will be described in the REMP.

Proposed ecological and biological monitoring of creeks and wetlands is described in Chapter 16 and Appendix 16 – Vegetation and Aquatic Ecology Monitoring Plan. This monitoring is designed to tie in with the surface water monitoring by undertaking monitoring at the same sites. Vegetation and aquatic ecology monitoring will be used to identify potential ecological impacts where water quality or water level monitoring has identified a potential impact.

Proposed monitoring of releases from the Port sediment ponds and monitoring in the estuarine / marine environment of the Skardon River is described in Chapter 17.


Page 12-70

The REMP will be developed and implemented to monitor, identify and describe any adverse impacts to surface water and groundwater environmental values, quality and flows due to the authorised mining activity. This will include monitoring the effects of the mine on the receiving environment periodically (under natural flow conditions). For the purposes of the REMP, the receiving environment is the waters of Namaleta Creek, Skardon River and wetlands within and surrounding the Project area downstream or down gradient of the authorised mining activity.

The REMP will address the requirements of the REMP Guideline (EHP, 2015). A report outlining the findings of the REMP, including all monitoring results and interpretations will be prepared annually. The report will include an assessment of background reference water quality, the condition of downstream water quality compared against water quality objectives, and the suitability of current release limits to protect downstream environmental values.

12.10.4 Management Measures in Response to Monitoring

12.10.4.1 Water Quality

The criteria for determining whether the Project has resulted in a change in water quality are described in Appendix 15, involving comparison of multiple percentiles of sample data from compliance sites against baseline (population) data and reference site data.

Where a defined change has occurred then Gulf will:

complete an investigation into the potential for environmental harm and provide a written report to

the administering authority in the next annual return outlining:

details of the investigations carried out

actions taken to prevent environmental harm.

Investigations will consider:

results of vegetation and aquatic ecology monitoring (Appendix 16)

activities in the catchment with potential to cause impacts

natural changes in the catchment and seasonal factors.

Should activities be demonstrated to have an impact on water quality and associated vegetation and aquatic ecology (as measured in accordance with the Vegetation and Aquatic Ecology Monitoring Program in Appendix 16) over a period of 12 months (i.e. a wet season and dry season) then Gulf will seek to identify the cause of the impact and implement management measures (e.g. engineering controls).

Should activities be demonstrated to have a long term impact on water quality and associated vegetation and aquatic ecology (as measured in accordance with the Vegetation and Aquatic Ecology Monitoring Program in Appendix 16) despite the implementation of management measures, then offsets will be proposed for significant residual impacts to MSES and / or MNES. Long term impacts will be measured over the operational life of the mine comparing vegetation and aquatic ecology pre mining to post mining.

12.10.4.2 Wetland Water Levels

The methodology for determining whether the Project has resulted in a change in wetland water levels is described in Appendix 15 and involves comparing wetland level logger data against modelled percentile ranges in baseline water level.


Page 12-71

Where, over a period of 3 or more months, monitored water levels within swamps exceed the 90th percentile or fall below the 10th percentile of the modelled water levels, Gulf Alumina will conduct an investigation into the potential cause of the variance considering:

rainfall

trends in water level relative to trends in rainfall

quantum of change (i.e. variance in cm) relative to quantum of natural change within wetlands

proximity of mining activities (noting that mining activities within 3 km of Bigfoot Swamp are not

scheduled to commence until Year 4 (2020) of mining and that mining activities within 1 km of

Lunette Swamp are not scheduled to commence until Year 3 (2020) of mining (2019))

proximity of aquifer pumping for mine water supply

changes in groundwater bore levels

results of vegetation and aquatic ecology monitoring

mining activities by other proponents in the area, in particular Metro Mining’s proposed mining

activities near Bigfoot Swamp.

Where a short term change (e.g. over a period of 12 months) in wetland water levels, resulting in impacts to vegetation and aquatic ecology, is considered to be a result of the Project’s mining activities, Gulf Alumina will:

cease pumping water from aquifers with hydrological connection to the wetlands

alter the location of mining away from the affected wetland and commence rehabilitation of the

nearer mining area

reduce mining activities in areas with potential for impact until such time as wetland hydrology is

restored.

increase buffer zones around wetlands if it is found that the proposed buffer zones provide

insufficient protection.

Should activities be demonstrated to have a long term impact on wetland water levels and associated vegetation and aquatic ecology (as measured in accordance with the Vegetation and Aquatic Ecology Monitoring Program in Appendix 16) despite the implementation of management measures, then offsets will be proposed for significant residual impacts to MSES and / or MNES. Long term impacts will be measured over the operational life of the mine comparing vegetation and aquatic ecology pre mining to post mining.

12.10.5 Groundwater Monitoring

The groundwater monitoring programme will include ongoing monitoring of the existing groundwater bores and additional bores. The bore number, location, purpose and summary of monitoring are described in Table 12-30.

The locations for the monitoring bore sites are shown in relation to the proposed bauxite mining pits and other bauxite mine infrastructure in Figure 12-18. The proposed monitoring bore network comprises existing bores and new bores. Reference bores provide information on groundwater upgradient of potential Project impacts. Compliance bores will be used for comparison to reference bores to assist in understanding potential Project impacts on groundwater. Prior to mining all bores will provide baseline groundwater data for the area.

The groundwater levels for all bores will be recorded with a continuous, automatic logger to determine any shallow groundwater responses to rainfall events and to changes in local pumping regimes. Manual readings of standing water levels will be measured with a water level dipper quarterly so as to capture


Page 12-72

data during the wet and dry seasons and for calibration of the automated instrumentation within bores fitted with pressure transducers.

It is intended that data will be downloaded from the pressure transducers on a quarterly basis at beginning and end of wet season and dry season. Manual water level measurements will be taken prior to downloading the data from the pressure transducer, such that the pressure transducer measurements can be calibrated.

Analysis of groundwater samples will be recorded at the existing and proposed monitoring locations listed in Table 12-30 at quarterly intervals. The samples will be tested at a NATA accredited laboratory for standard suites of analytes. Sample collection and transportation will follow guidelines and protocols provided within the Monitoring and Sampling Manual 2009 (EHP, 2010), with consideration given to sampling techniques for groundwater in a low yield bores.

Appendix 15 describes the parameters for monitoring and frequency of monitoring for a REMP

saline water intrusion in Namaleta aquifer bores

treated effluent irrigation area

Port area including landfill and bioremediation pad.

The following information will be recorded for all groundwater monitoring:

the date on which the sample was taken

the time at which the sample was taken

the monitoring point at which the sample was taken

the results of all monitoring and details of any exceedances of the conditions of the EA.

Bore construction, maintenance and decommissioning will be carried out in compliance with the guidelines of “Minimum Bore Construction Requirements for Water Bores in Australia (Edition 3)”, ARMCANZ (2012), to prevent or minimise impacts to the environment and further to ensure the integrity of the bores to obtain accurate monitoring data for the Project.

12.10.6 Saline Water Ingress

Mining of the pits and water supply from the Namaleta borefield, is predicted to result in potential drawdowns of 0.4 m at reaches of the Creek immediately adjacent to the former kaolin mine (refer to Chapter 13 for groundwater modelling results). A reduction in local baseflow has the potential to change normal tidal behaviour of Namaleta Creek that could result in increased seasonal saline excursion upstream.

Appendix 15 describes the groundwater monitoring plan to detect saline water incursion (bores G3, G4, G12, G13 and G14 in Table 12-30) and inform operational decisions such as borefield pumping. In addition the exact location of future supply bores (refer Chapter 6) in the area will be chosen to avoid impacting baseflow and inducing potential intrusion of saline water.


Page 12-73

Table 12-30 Groundwater Monitoring Network

Monitoring Point

Location Details Location (GDA94 – Zone 54) Bore Purpose Monitoring

Easting (m) Northing (m)

Reference Bores

G1 Near Lunette Swamp and camp – used for camp supply

611810 8687604 Conditions at the top of Lunette Swamp catchment; indicative of conditions near Pits 10, 11, 12 and 13. Supply water to camp from bore upgradient of impacts. Water quality historically suitable for potable camp water.

Water levels recorded with continuous logger; Sampling and laboratory testing; Continuous logging EC. Bore water quality will also be tested against Australian Drinking Water Quality guidelines.

G9 Near haulroad, west of Pit 3

614121 8692982 Aquifer conditions at central mining pits (predominantly upgradient of Pit 3 area) and upgradient of Bigfoot Swamp

Water levels recorded with continuous logger; Sampling and laboratory testing.

G10 Near haulroad in line with Bigfoot Swamp

614846 8695174 Aquifer conditions at the northern end of mine (predominantly upgradient of Pits 3, 2 and 6) and upgradient of Bigfoot Swamp


G15 New bore upgradient of Lunette Swamp

614307 8689722 Aquifer conditions upgradient of Lunette Swamp and all mine pits (Pits 5, 8, 9, 10)


G16 New bore upgradient of Pits 14 and 15

610300 8685023 Aquifer conditions upgradient of Namaleta Creek and southern mine pits (Pits 14 and 15)


C2 Near Bigfoot Swamp 613940 8695676 Aquifer conditions up gradient from Bigfoot Swamp Water levels recorded with continuous logger; Sampling and laboratory testing.

Compliance Bores

C1 West of proposed mining

612629 8690559 Groundwater conditions upgradient of Lunette Swamp but downgradient of Pits 4, 5, 8, 9 and 10


G2 Former kaolin mine wet plant area (decommissioned)

610596 8687043 Aquifer condition upgradient of kaolin mine, within proposed mining area (Pit 12), downgradient Pits 11 and 13


G6 West end of airstrip 608861 8688522 Aquifer condition at downgradient of Pits 11,12, 13 Water levels recorded with continuous logger; Sampling and laboratory testing.


Page 12-74

Monitoring Point



G3 North of Namaleta Creek

609635 8686879 Namaleta Creek and aquifer condition at downgradient of Pits 11,12, 13 and to monitor potential migration of saltwater interface resulting from water use from Namaleta aquifer and kaolin pit areas.

Water levels recorded with continuous logger;

Sampling and laboratory testing.

Continuous logging EC, TDS and physico-chemical.

G5 Port Area 616612 8699558 Downgradient of Port infrastructure area Water levels recorded with continuous logger; Sampling and laboratory testing.

G4 Namaleta South 609339 8686392 Conditions south of Namaleta Creek in palaeochannel aquifer (downgradient of Pits 14, 15) and to monitor potential migration of saltwater interface resulting from water use from Namaleta aquifer and kaolin pit areas.




C3 Skardon River 615194 8692649 Between mining lease boundary and Skardon River South Arm. Aquifer conditions downgradient of central mining pits (Pit 3 area)


G8 North of airstrip 609603 8690668 Groundwater conditions down gradient from Lunette Swamp and Pits 11, 12, 13)


G11 Skardon River 615671 8695166 Aquifer conditions at the northern end of mine down gradient of Pit 3.


G7

West of mining, Beach road

606990 8688615 Conditions at western end of mining area downgradient of Pits 11,12, 13)


G13 Downstream Namaleta Creek

609329 8687070 Existing bore, to be monitored for groundwater conditions downstream in Namaleta Creek and to monitor potential migration of saltwater interface resulting from water use from Namaleta aquifer and kaolin pit areas.

Downgradient of Pit 12

Water levels recorded with continuous logger; Sampling and laboratory testing; Continuous logging EC, TDS and physico-chemical.


Page 12-75

Monitoring Point











G17 Near proposed water supply production bores at the Port area

615305 8698170 Monitor groundwater levels near proposed water supply bores at Port area



G18 Near proposed Namaleta borefield, south of Namaleta Creek

609807 8685933 Monitor groundwater levels near proposed water supply bores in Namaleta Borefield and to monitor potential migration of saltwater interface resulting from water use from Namaleta aquifer and kaolin pit areas.




G29 Downgradient of Bigfoot Swamp

612793 8697010 Monitor groundwater levels downgradient of Bigfoot Swamp in alluvial sand aquifer.



G30 Downgradient of Lunette Swamp

611696 8690871 Monitor groundwater levels downgradient of Lunette Swamp in alluvial sand aquifer.



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ML 40082

ML 40069

SKARDON RIVER

NAMALETA CREEK

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G10G11

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Figure12-18

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Existing and ProposedMonitoring Bores



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Page 12-77

12.10.7 Targeted Monitoring Bores

Groundwater monitoring bores will be installed upgradient and downgradient of the following Project activities with the potential to contaminate groundwater:

landfill near the Port

bioremediation pad – currently located near the former kaolin mine wet plant area but proposed for

relocation to the landfill area at the Port once prior to mining in this area (Year 2 or 3)

hydrocarbon storage at the port

effluent irrigation area.

The monitoring programme for these bores is described in Appendix 15 and Chapter 8 (effluent irrigation area) and Chapter 11 (landfill, bio-remediation pad and hydrocarbon storage). Bores will also become operational at commencement of the Project operations and will include monitoring of specific parameters, as per Table 12-2b.

12.10.8 Management Measures in Response to Monitoring

12.10.8.1 Groundwater Quality – Mining Areas

The criteria for determining whether the Project has resulted in a change in groundwater quality in mining areas are described in Appendix 15, involving comparison of multiple percentiles of sample data from compliance sites against baseline (population) data and reference site data.






Investigations will consider:


activities with potential to cause impacts

natural changes in groundwater quality

groundwater levels

seasonal factors.

Should mining activities be demonstrated to have an impact on groundwater quality and associated vegetation and aquatic ecology (as measured in accordance with the Vegetation and Aquatic Ecology Monitoring Program) over a period of 12 months (i.e. and wet season and dry season) then Gulf will seek to identify the cause of the impact and implement management measures (e.g. engineering and operational controls).

Should mining activities be demonstrated to have a long term impact on groundwater quality and associated vegetation and aquatic ecology (as measured in accordance with the Vegetation and Aquatic Ecology Monitoring Program) despite the implementation of management measures, then offsets will be proposed for significant residual impacts to MSES and / or MNES. Long term impacts will be measured over the operational life of the mine comparing vegetation and aquatic ecology pre mining to post mining.


Page 12-78

12.10.8.2 Groundwater Quality – Saline Water Intrusion

The criteria for determining whether the Project has resulted in a change in salinity in Namaleta aquifer bores are described in Appendix 15, involving comparison of multiple percentiles of sample data from compliance sites against baseline (population) data.






During operations Gulf Alumina will also monitor EC and TDS levels in water supply bores in the Namaleta aquifer (i.e. AKP02, AKP03, AKP04, AKP05 and Supply Bore #4 in Chapter 6, Figure 6-9). Any investigation into increased salinity in monitoring bores will consider:

EC and TDS in water supply bores

volume of pumping from each water supply bore (based on flow meter readings)

period over which water was pumped from each water supply bore

water level in water supply bores

water level in monitoring bores


rainfall events.

Should an investigation determine that aquifer pumping and / or mining activities have resulted in saline water intrusion to bores, resulting in impacts to groundwater dependent vegetation and aquatic ecology, Gulf will:

cease pumping those bores used for mine site water supply which may have resulted in saline water

intrusion

not recommence pumping until salinity levels in bores are the same as population percentiles.

Gulf Alumina will continue to investigate other potential aquifers for water supply, as shown in with:

proposed supply bores #1, #2, #3 near the Port area

existing production bore G5 at the Port area

proposed supply bore #5 and Lunette Bore near the Lunette aquifer.

These alternative water supplies will be used to reduce pressure on the Namaleta aquifer.

12.10.8.3 Groundwater Quality – Port Area and Treated Effluent Irrigation Area

The criteria for determining whether the Project has resulted in a change in groundwater quality downgradient of potential contamination area are described in Appendix 15, involving comparison of multiple percentiles of sample data from compliance sites against baseline (population) data and reference site data.






Page 12-79


Investigation will consider the potential source of any contamination, measures to prevent future contamination (e.g. design and engineering controls) and remediation of potential contamination.

12.10.8.4 Groundwater Levels

The methodology for determining whether the Project has resulted in a change in groundwater levels is described in Appendix 15 and involves comparing groundwater level logger data against modelled percentile ranges in baseline groundwater level.

Where, over a period of 3 or more months, monitored water levels within groundwater exceed the 90th percentile or fall below the 10th percentile of the modelled groundwater levels, Gulf Alumina will:

Compare water levels in compliance bores with water levels in reference bores over the period

Where trends in water levels in compliance bores are similar to those of reference bores then no

action will be taken

Where trends in water levels in compliance bores are different to those of reference bores, then

Gulf will Alumina will complete an investigation into the potential for environmental harm and

provide a written report to the administering authority in the next annual return outlining:



Investigations into the potential cause of the variance considering:

rainfall

trends in water level relative to trends in rainfall

quantum of change relative to quantum of natural change within bores

proximity of mining activities to bores

proximity of bores used for aquifer pumping for mine water supply

changes in wetland water levels.

mining activities by other proponents in the area, in particular Metro Mining’s proposed mining

activities near Bigfoot Swamp.

results of vegetation and aquatic ecology monitoring.

Where Project activities result in a short term change (e.g. over a period of 12 months) in bore water levels that is considered to be resulting in an impact to groundwater dependent ecosystems, Gulf Alumina will:

cease pumping water from aquifers with hydrological connection to the groundwater dependent

ecosystems

alter the location of mining away from the affected groundwater dependent ecosystems and

commence rehabilitation of the nearer mining area

reduce mining activities in areas with potential for impact until such time as groundwater

dependent ecosystems hydrology is restored.

increase buffer zones around groundwater dependent ecosystems if it is found that the proposed

buffer zones provide insufficient protection.


Page 12-80

Should activities be demonstrated to have a long term impact on groundwater water levels and associated, dependent vegetation and aquatic ecology (as measured in accordance with the Vegetation and Aquatic Ecology Monitoring Program in Appendix 16) despite the implementation of management measures, then offsets will be proposed for significant residual impacts to MSES and / or MNES. Long term impacts will be measured over the operational life of the mine comparing vegetation and aquatic ecology dependent on groundwater pre mining to post mining.

12.11 Risk Assessment

A risk assessment assessing the likelihood and significance of impacts to surface water and groundwater quality from the Project is provided in Table 12-31. The risk assessment considers mitigated risk; that is, the impact from the Project with the implementation of management measures. The risks to water quality are low to medium.

Table 12-31 Risk Assessment and Management Measures for Impacts to Water Quality

Environmental Value

Impacts / Emissions / Releases

Proposed Management Practices

Likelihood Consequence (Magnitude)

Risk Rating

Surface water quality (watercourses and wetlands)

Increased sedimentation. Refer Section 12.8.

Refer Section 12.9 and Section 12.10.

Unlikely Minor Low

Hydrocarbon or chemical contamination. Refer Section 12.8.


Unlikely Minor Low

Contamination from waste or bio-remediation pad. Refer Section 12.8.


Unlikely Minor Low

Groundwater quality

Hydrocarbon or chemical contamination. Refer Section 12.8.


Possible Minor Medium

Contamination from waste or bio-remediation pad. Refer Section 12.8.


Possible Minor Medium

12.12 Cumulative Impacts

Cumulative impacts are considered for all known or reasonably foreseeable projects with the potential for spatial and temporal impacts in combination with the Skardon River Bauxite Project. The projects in the Cape York region which potentially meet these criteria are:

Metro Mining Ltd’s (formerly Cape Alumina Ltd’s) Bauxite Hills project

Rio Tinto’s existing bauxite mining operation near Weipa

Rio Tinto’s proposed South of Embley Project


Page 12-81

Rio Tinto’s existing and proposed projects are not considered to have a cumulative impact on water quality with the Skardon River Bauxite Project as the projects are approximately 90 km apart, do not share the same catchments or hydrology and do not operate in the same near shore waters.

The only project considered to have a cumulative impact with the Skardon River Bauxite Project is the Bauxite Hills project. Based on publically available information (EPBC Act Referral), the Bauxite Hills project would be for an integrated bauxite mine adjacent (east and west) to the Project and port located to the immediate south of the Skardon River. The Referral for the Bauxite Hills project describes a 2 Mtpa bauxite mine with over 21 year mine life and a 61.5 Mt indicated and inferred resource (In November 2015 this was revised to a 5 Mtpa operation for 12 years, but no impact assessment is publically available for this scenario). The Bauxite Hills project includes a new barge loading facility on the Skardon River, barging of bauxite to an offshore transhipment area, workers camp and haul road transport corridor. A mine plan from the Referral for the Bauxite Hills project is provided in Figure 12-19, which shows mining to the east and west of the Skardon River Bauxite Project.

Figure 12-19 Conceptual Mine Plan – Bauxite Hills Project

For the purpose of assessing cumulative impacts to groundwater, Chapter 13 demonstrates that groundwater gradients for shallow aquifers are similar to surface water catchments and assesses cumulative impacts on groundwater hydrology.

The Bauxite Hills Project is not located within the Namaleta Creek or Lunette Swamp catchments and hence there is not expected to be cumulative impacts to surface water or groundwater quality in Namaleta Creek and Lunette Swamp.

Based on publically available information, the Bauxite Hills project will include mine pits in close proximity to Bigfoot Swamp. Therefore, there may be cumulative water quality impacts on Bigfoot


Page 12-82

Swamp dominated by Bauxite Hills project’s activities. As Bigfoot Swamp occurs in close proximity Metro Mining’s leases, it is expected that they will undertake ongoing monitoring of water levels and quality and, in consultation with Gulf Alumina, implement any management measures or investigations required by monitoring results.

Both project’s mining activities occur within upper catchment of the wetland complex to the west and north-west of both Project’s mining leases. There is potential for cumulative surface water quality impacts on this wetland complex, although due to separation distance and proposed management measures expected from both projects, impacts are likely to be minimal. As operations on Metro Mining Ltd’s ML 20689, are located directly west of Gulf Alumina’s ML 40082, Gulf Alumina will seek a cooperative relationship with Metro Mining and the landowners for access, establishment and ongoing monitoring of water quality in these wetland areas.

The Skardon River Bauxite Project will not impact the catchments to the east of Skardon River South Arm where the mining is proposed for the Bauxite Hills project. Nevertheless, the Skardon River South Arm (estuarine environment) may be impacted by runoff from both the west, mainly from the Skardon River Bauxite Project, but also small areas of the Bauxite Hills project, and from the east (Bauxite Hills Project).

Gulf Alumina has proposed a buffer around the fringing supratidal wetland area along the Skardon River South Arm, where this buffer extends into Gulf Alumina’s mining lease. Publically available information from Metro Mining indicates that this area within 100m of the Skardon River may contain a haul road to support movement of bauxite within their tenements to a new proposed Port location. There are potential cumulative impacts to surface water quality in this wetland. This area will be subject to ongoing and cooperative monitoring to establish if impacts are occurring and the potential cause of impacts.

Gulf Alumina will seek to cooperate and consult with Metro Mining on all aspects of water management, water monitoring, identification of potential cumulative impacts and measures to mitigate impacts.

12.13 Conclusion

The watercourses and catchments potentially impacted by the Project are the Skardon River and Namaleta Creek. The Skardon River is considered a predominantly estuarine system, consisting of freshwater systems within its upper reaches. The Skardon River catchment is approximately 480 km2, which is relatively small compared to other catchments on Cape York. Namaleta Creek is a localised drainage, tidally influenced in its lower reaches and with a catchment of 37 km2, of which 21 km2 lies upstream of the eastern mine boundary.

The freshwater wetland ecosystems within and surrounding the Project area are Lunette Swamp, Bigfoot Swamp, Namaleta Creek, a tributary of Namaleta Creek, supratidal wetlands to the west of the Skardon River South Arm and wetland complexes to the west and north of the Project area.

Environmental values and water quality objectives have been nominated for the Project based on the requirements of the Queensland Water Quality Guidelines. Sufficient data is available for some water quality parameters to set local water quality objectives. Where there is an absence of sufficient information to set local water quality objectives, default water quality objectives based on the Australian Water Quality Guidelines have been proposed.

Surface water quality and surface water depths have been monitored at locations within and surrounding the Project area. Surface water level in all locations is seasonally variable, with elevated water levels in the period February to March each year, co-incident with the wet season. pH is moderately acidic to neutral, which is a reflection of the geology of the catchment. The majority of EC is very low, with the 80th percentile value of 50 µS/cm. Dissolved metals values are very low across almost


Page 12-83

all sites, when compared with the AWQG, other than copper. Most samples results are below the detection limit. Nutrient values (TN, TP) are low across all sites.

Groundwater quality and groundwater levels have been monitored at bores within and surrounding the Project area. Groundwater level in all aquifers is seasonally variable, with elevated groundwater levels in the period February to March each year, co-incident with the wet season. pH is slightly acidic in all aquifers, which is a reflection of the geology of the site. EC is low across all aquifers. Dissolved metals values are very low across almost all bores in all aquifers, when compared with the AWQG trigger values, with the exception of dissolved copper and dissolved zinc. Nutrient values (TN, TP) are low across all bores.

The potential impacts to surface water quality are:

low risk of uncontrolled release of water with high sediment loads from bauxite mining areas (not

expected as mining areas will be internally draining)

stormwater runoff with sediment from haul roads, including the Namaleta Creek crossing area

increased sedimentation of waterways during construction and vegetation clearing


infrastructure areas.

The potential impacts to groundwater quality are:

localised impacts to groundwater quality hydraulically down-gradient from the landfill, treated

effluent irrigation area and bio-remediation pad through seepage

uncontrolled release of potentially hydrocarbon and chemicals

The Project’s water management strategy is described in Chapter 6 and has been designed to minimise the potential for release of sediment laden water from mining areas and to control runoff from the Port infrastructure area.

Chapter 15 and Chapter 16 described the proposed vegetation buffer zones around wetlands. These buffer zones will act to reduce potential impacts from sediment laden runoff.

Measures to prevent contamination of surface water and groundwater from hydrocarbons, chemicals in infrastructure areas, and from the bio-remediation pad are described Chapter 11. The proposed measures will minimise the risk of release of contaminants to water bodies.

Design and management of the landfill and waste storage areas are described in Chapter 8. The proposed measures will minimise the risk of release of contaminants to water bodies.

Design and mitigation measures for impacts to water quality from construction of the Namaleta Creek crossing and the crossing of the mapped wetland to the south are described in Chapter 16.

An erosion and sediment control plan (ESCP) will be developed for the Project construction and operations, with localised erosion and sediment control structures to be designed within the recommended guidelines of the International Erosion Control Association (IECA) Manual (IECA, 2008).

A comprehensive surface water and groundwater monitoring plan has been proposed to assist in determining potential Project impacts and to inform potential mitigation measures. With the implementation of proposed mitigation measures, environmental objectives and performance outcomes are expected to be achieved and the risks to surface water and groundwater quality are low to medium.

chapter 12 – water values and quality - metro mining · 2018-08-09 · skardon river bauxite...

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