tailings storage facility – rav 8 pit tectonic …

SOIL & ROCK ENGINEERING

Project no: PS5720.03 17 June, 2005 Our ref: PS5720.03 AA inpitnoi Rev 0 PROJECT: TAILINGS STORAGE FACILITY – RAV 8 PIT

CLIENT: TECTONIC RESOURCES NL

LOCATION: RAV 8 OPERATIONS

SUBJECT: NOTICE OF INTENT – SUMMARY ________________________________________________________________________________ Tectonic Resources NL proposes to store tailings from the new conventional floatation and CIP/CIL plant at RAV 8 in the RAV 8 Pit. The pit is located approximately 800m east of the existing workshop and offices, at the RAV 8 Mine, on Mining Lease number M74/13. Nickel Ore is currently mined from the RAV 8 Pit and associated underground workings. Underground mining is expected to cease in 2005. It is planned to develop and mine new gold and polymetallic ore deposits, at Kundip and Trilogy, 16 and 27 km southeast of Ravensthorpe respectively. The extraction of these ores will necessitate the construction of a new processing plant. The tailings slurry produced will require containment and storage. It is proposed to utilise the RAV 8 Pit to provide for future tailings storage requirements. A pipeline corridor from the plant to the pit will be established, primarily along existing road alignments. Little or no disturbance of land / clearing will be performed, in order to allow the project to proceed. The final surface area of the tailings storage area after the pit is filled will be approximately 8.27ha. The maximum depth of the RAV 8 Pit is approximately 129m. The RAV 8 Pit has storage capacity of approximately 3.3 x 106 m3. This is more than sufficient capacity to store the projected tailings production of 2.4 Mt over a project life of 6 years (at this stage), assuming an average insitu tailings density of 1.50t/m3 (dry). The design concept for the pit incorporates, a surface return water recovery system in order to maximise water return to the plant and hence maximise tailings density. Monitoring bores adjacent to the pits would be utilised as recovery bores, if required. A similar design concept to that proposed in this document for the RAV 8 Pit has been utilised successfully at the following sites:

• Redeemer Pit Agnew. • Fisher Pit Jundee. • Perch, Perch North and Perch West Pits Plutonic Gold Mine, near Meekatharra. • South Bounty and East Bounty Pits Bounty Gold Mine, Forrestania. • HP and Carolyn Pits Lawlers Gold Mine, near Leinster.

PS5720.03 AA inpitnoi Rev 0


• Venture Pit, Central Norseman Gold Corporation. • Gwendolyn Pit, Herbert Mining, Diemals. • K1 Pit, Marymia Gold Operation, Meekatharra. • K1SE Pit, Marymia Gold Operation Meekatharra.

The tailings storage has been assigned a hazard rating of Low, Category 3, based on classification criteria outlined in Table 1 and Figure 1 of the Department of Industry and Resources (DoIR), (formerly the DME) (1999) document titled ‘Guidelines on the Safe Design and Operating Standards for Tailings Storage’. A geochemical characterisation of the tailings indicated that the oxide ore types are Non Acid Forming, however one primary ore type is Potentially Acid Forming – [Long Lag]. Rehabilitation strategies will be developed in order to minimise the potential environmental impact from acid mine drainage. A geotechnical assessment of the pit indicates that the pit can be safely operated as a tailings storage facility provided liberated tailings slurry water is removed so that the risk of pit wall failures are reduced. It must be stressed that the safe operation of the tailings storage facility relies upon the implementation of all the tailings operation, management, inspection and maintenance procedures to maximise water return and to reduce the potential for a pit wall failure. Tectonic Resources NL make the following commitments in respect to the R8TSF:

(i) Minimal disturbance of land will be performed in order to allow the project to proceed. Pipelines to and from the pit will be bunded to prevent spillage of tailings or return water into the surrounding area in the event of pipeline failure.

(ii) An adequate total freeboard of 0.68m will be available to store the design storm event

of a 1 in 100 year, 72 hour storm during the operation of the facility. (iii) Monitoring / recovery bores adjacent to the pit will be utilised to monitor water levels

and water quality. Base line water levels and samples will be taken prior to tailings deposition to the pit to monitor existing water quality. Routine water samples will be taken every three (3) months from monitoring bores for the pit to check water quality, with water levels in the monitoring bores read on a monthly basis.

(v) Manage and operate the tailings storage in general accordance with the Operations

Manual provided with the Notice of Intent. Independent audits will be performed on a yearly basis.



(vi) A detailed rehabilitation plan will be developed. At this stage, it is planned to cover the PAF tailings with oxide tailings and waste to form a storm and release cover.

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Project no: PS5720.03 17 June, 2005 Our ref: PS5720.03 AA inpitnoi Rev 0 PROJECT: TAILINGS STORAGE FACILITY – RAV 8 PIT

CLIENT: TECTONIC RESOURCES NL

LOCATION: RAV 8 OPERATIONS

SUBJECT: NOTICE OF INTENT ________________________________________________________________________________ 1.0 INTRODUCTION This document presents the details required, by the Department of Industry and Resources, (DoIR) Western Australia, for a Notice of Intent (NOI) for the use of the RAV 8 Pit for the storage of tailings. The RAV 8 Tailings Storage Facility (R8TSF) is located approximately 800 m east of the existing workshops and offices, at Tectonic Resources NL RAV 8 Operations. Nickel Ore is currently mined from the RAV 8 Pit and associated underground workings. Underground mining is expected to cease in 2005 when all known mineralization has been exhausted within a 300m envelope around the open pit and 100m below the workings. It is planned to develop and mine new gold and polymetallic ore deposits, at Kundip and Trilogy, 16 and 27km southeast of Ravensthorpe respectively. The extraction of gold and associated minerals will necessitate the construction of a new processing plant and as a by product the production of a tailings slurry that will require containment and storage It is proposed to utilise the RAV 8 Pit to provide for future tailings storage requirements. A pipeline corridor from the plant to the pit will be established, primarily along existing road alignments. Little or no disturbance of land / clearing will be performed, in order to allow the project to proceed. For details of the full operation description, the operation environmental impact assessment, management commitments and the project social impacts, reference should be made to the original mining NOI for the RAV 8 Pit and the Phillips River Gold Project NOI. Details contained in this report were compiled in accordance with the requirements of the DoIR1,2 documents ,‘Guidelines on the Safe Design and Operating Standards for Tailings Storage’, dated May 1999 and ‘Guidelines to help you get Environmental Approval for Mining Projects in Western Australia’, dated March 1998, as appropriate. The tailings storage has been assigned a hazard rating of Low, Category 3, based on the classification criteria outlined in Table 1 and Figure 1, of the above guidelines. A tailings storage data sheet and explanatory notes are attached as Figures 1 and 2. A Tenement Location Plan is attached as Figure 3.

PS5720.03 AA inpitnoi Rev 0 Page 2


1.1 Location The RAV 8 Pit is located solely on Mining Lease M74/13 approximately 800m east of the existing workshops and offices. The approximate centre of pit is on AMG coordinates 6,278,285m north and 249,440m east or mine grid 11,000m north and 6,000m east. The mining lease is located 25kms east of the town of Ravensthorpe; access to the site is via the main South Coast Highway that links Ravensthorpe to Esperance. The highway passes through the lease area and serves as an ideal transport and access route for delivery of the nickel sulphide ore offsite and receival of supplies for the project. The site of the project is bordered by Vacant Crown Land [classified as Water Reserve] to the north and free hold farming to the south. 1.2 Ownership Mining Tenement M74/13 is 100% owned by the public company Tectonic Resources NL. Part of the lease includes the farming properties owned freehold by Tectonic Resources NL (Oldfield location 317) and the Burton Family (Oldfield location 62). The total area covered by the lease is 427.6 hectares. 1.3 Existing Facilities Construction of the RAV 8 Nickel Project commenced in March 2000. It involved the construction of an open pit, waste rock stockpiles, processing facility, power station, reverse osmosis plant, a saline water storage dam and associated offices and workshop areas. The affiliated mill processing facility consisted of a crushing & screening circuit, a grinding circuit (ball mill), and an ore floatation circuit plus infrastructure associated with the disposal of thickened and filtered tailings. A decision to close the onsite treatment plant and truck the ore to Kambalda was made in November 2001. Onsite processing of the nickel sulphide ore at RAV 8 ceased on December 30th 2001. The crushing and screening circuit was dismantled and removed from site in 2002. The ore floatation circuit and infrastructure associated with the disposal of thickened and filtered tailings is currently retained on site and has been placed under care and maintenance. The project still generates its own power but has removed the reverse osmosis plant. The emergency tailings storage facility was divided into three (3) cells to provide a total capacity of 42,000 m3 (each cell was designed to contain 40,000 tonnes of material). The western waste dump surrounds the cells on three sides and will be shaped to encapsulate the cells prior to decommissioning.



The emergency tailings storage cells were designed as part of the onsite facilities to contain tailings produced by the plant during periods when the thickener and/or drum filter was undergoing maintenance. The tailings initially deposited into the emergency tailings storage [ETS] cells were progressively excavated and transported in a dry to semi-dry state [approx. 85% solids] to designated areas within the waste dump. These areas were covered on a continual basis as the western waste dump was constructed. In the long term all the ETS cells will be covered by the construction of the western waste dump – any tailings that remain within the cells will be permanently encapsulated within the dump. The eastern cell was encapsulated by waste rock prior to March 2001. Following closure of the mill, all remnant dry tailings material stacked on the ROM pad was trucked to the top of the western waste dump and pushed down over the middle storage cell; this was completed in September 2002. The western cell currently has a capacity of 9,840 m3, which is sufficient to contain any onsite contaminants. Sufficient non-acid forming oxide material is stockpiled next to the storage facility to cover the western cell. The final capping over the cells will be mounded to shed incident rainfall. Tectonic Resources NL outlined their intention in the NOI to dispose of dry tailings in the ETS cells and within the confines of the western waste dump. The initial application sought to accommodate 120,000 m3 (estimated insitu dry density of 1.4 t/m3) of dry tailings. An addendum to the NOI was approved in 2001 to increase the volume of tailings contained within the western waste dump to 190,000 m3 over a two (2) year operating period. A total of 136,062 m3 (190,486 t) of tailings material was produced as an end product of processing the RAV 8 ore deposit. 2.0 GENERAL INFORMATION A tailings storage data sheet is attached as Figure 1, explanatory notes are attached as Figure 2. 2.1 Process Type Ore processing will utilise a conventional flotation and CIP/CIL. 2.2 Rated Throughput The ore through put of the mill will be between 0.4 and 0.8 million dry tonnes per annum. 2.3 Ore Type



Ore types comprise oxide and primary ore from the Trilogy and Kundip Pits. Tectonic Resources NL advise that the ores will be processed in campaigns. 2.4 Tailings Production Refer to Section 2.2. 3.0 TAILINGS PROPERTIES 3.1 Mineralogy Geochemical characterisation testwork was undertaken under the direction of Graeme Campbell & Associates (GCA). The following table is presented of the ‘enriched’ elements in various tailings solids samples subjected to geochemical testing:

Element Kundip Oxide (mg/kg or %)

Kundip Primary (mg/kg or %)

Trilogy Oxide (mg/kg or %)

Ag 3.7 3.5 16 Cu 2,800 1,900 780 Cd 0.2 1.1 0.1 Pb 200 440 1,300 Co 120 550 19 Hg 0.82 0.09 2.5 As 140 37 520 Bi 4.0 5.0 150 Sb 0.77 0.73 56 Se 1.9 1.7 8.4 Mo 17 33 54 B 110 <50 480

Total S 0.31% 9.1% 0.10% Sulphide S 0.20% 9.1% 0.08%

3.2 Residual Process Chemicals The following data is presented based on laboratory testwork. Total Cyanide ex-plant 300 ppm* Total Cyanide in tailings return water 100 ppm* Free Cyanide ex-plant approx 250 ppm* Free Cyanide in tailings return water less than 50 ppm* Salinity of process water 26,000 to 29,000 mg/L Salinity of tailings return water similar to process water



pH of slurry ex plant 8.4 – 8.7 pH of return water approx 7 * Note - detox of the tailings prior to discharge may be undertaken after 2 years. 4.0 SITE SELECTION 4.1 Background To limit the requirement to clear and disturb new areas of land it is proposed to fill the RAV 8 Pit to provide tailings storage capacity for the project. The volume available for tailings storage within the RAV 8 Pit, which is approximately 125m deep, is approximately 3.5 x 106 m3, with approximately 2.5 x 106 m3 being below the original groundwater level. The volume available for tailings storage within the underground workings beside and below the RAV 8 Pit is 0.25 x 106 m3. In order to maximise the filling of voids within the underground workings the initial tailings deposition will be into the underground workings. The tailings deposition line taken into the workings via the portal at RL 1100 and tailings discharge point will be located within the workings at RL1080 with tailings allowed to flow down the workings which plunge at approximately 30o to the southwest. With a volume of approximately 0.25 x 106 m3 within the workings it is expected that the tailings will displace some water, which will accumulate within the mine after the dewatering is turned off, and gradually build up within the workings to exit into the base of the pit after a period of between 3 months to 6 months depending on the discharge rate and the density achieved within the underground workings. After the underground workings have been filled it is expected that the tailings will ‘emerge’ from the underground workings into the pit at the RL1044m level. Tailings deposition will then be undertaken from the pit rim via a single point discharge. A pipeline corridor from the plant to the pit will be established, primarily along existing road alignments. Little or no disturbance of land / clearing will be performed, in order to allow the project to proceed. Significant infrastructure, roads, reticulated power, return water sumps and water pipelines are already in place and can readily be utilised for this project. The proposed R8TSF utilises an existing pit which has been mined. Drilling has confirmed that no economic mineralisation is present below the existing pit. Hydrogeological3 and Geotechnical Assessments4 of the pit area have been undertaken as part of the development of the pit or during the life of the pit. A Geotechnical Assessment of the pit is presented in Attachment 1. 4.2 Climate



The climate of the Ravensthorpe area is typically dominated by hot dry summers and cold wet winters with potential evaporation greater than the annual rainfall. The following climatic data has been used in the design:

(i) Average annual rainfall is approximately 425 mm; (ii) Average annual evaporation is estimated at 1,850 mm/year; and (iii) Rainfall intensity estimation for Ravensthorpe for a 1 in 100 year ARI 72 hour storm

event. 4.3 Landform and Soils A large percentage of M74/13 is on elevated ground, however, the northern extremity of the open pit cuts across the path of a surface drainage system emanating from slightly undulating country (approx. 1 km) to the northwest of the site. Kim Bennett (Tectonic Resources NL) advised that the diversion channel, which was located on the outer edge of the eastern pit wall, was redirected in 2003 to enhance the long-term stability of the northern and eastern pit walls. The diversion channel now directs uncontaminated water from the upper part of the catchment away from the lease area and into the Bandalup Creek system, approx. 0.5 km east of the site. The ground surrounding the pit grades gently to the south. The subsoil conditions at the RAV 8 Pit comprise a thin veneer of soils overlying a combination of weathered felsic and ultramafic rocks. 4.4 Geology The geology of the pit comprises an ultramafic rockmass plunging at moderate angles hosting mineralisation of 1m to 9m in thickness located in close proximity to a contact with felsic rocks (quartzite). The contact is located in the footwall and is frequently sheared and fractured. 4.5 Hydrogeology A hydrogeological assessment of the RAV 8 Pit has been undertaken based on data supplied by Rockwater Pty Ltd3. Aquifers in the project area are generally associated with joints, fractures and zones of alteration/weathering in Archean ‘greenstone’ rocks. It is understood the original groundwater was between 20m and 30m below the original ground surface (ie prior to mine de-watering). The groundwater is saline (20,000mg/L to 25,000mg/L). From the information provided and the performance of the pit, it was concluded the proposed development of the RAV 8 Pit as a TSF is unlikely to impact on the existing groundwater conditions in the immediate area of R8TSF provided supernatant water recovery is undertaken.



4.6 Hydrological Characteristics 4.6.1 Surface Water There are no named drainage lines through the area of RAV 8 TSF. The RAV 8 Project area drains to the east south east and the project area is part of the ‘greater’ Bandalup Creek catchment system. The catchment area of the mine water storage dam to the south of the RAV 8 Pit is approximately 75 hectares. Part of this catchment lies to the west – northwest of the plant site. The upper catchment area measures 41 ha. In order to minimise the amount of water held in the water storage dam, runoff from the upper catchment is contained within a small diversion dam to the northwest of the saline water storage dam. The volume of fresh water is relatively small (approx. 2 800 m3), on a regular basis this fresh water is pumped out of the diversion dam. The landowner wishes to retain this diversion dam for watering of stock within this paddock. 4.6.2 Design Floods The pit is surrounded by a bund thus any watershed into the storage area will be by incident rainfall only. No creek diversion works are required for the tailings storage. The storage will be operated such that an adequate total free board of 0.68m to contain the design rainfall event of a 1 in 100 year ARI 72 hour storm event (2.5 mm/hour) is always provided, this will only be an issue when the facility is nearly full. At start up the pit will have a freeboard in excess of 100m. 5.0 TAILINGS STORAGE FACILITY STRUCTURE The recommended operation of the storage is aimed at:

• minimising water losses from evaporation and seepage; • maximising water return to the plant, where practical; and • maximising tailings storage capacity.

The following environmental considerations have been incorporated into the tailings storage design.

(i) Following initial tailings deposition into the underground workings, refer to Section 4.1, tailings in the form of a slurry will be discharged sub-aerially initially from the northern end of the pit by a single open ended discharge and then after nominally six months from the southern end of the pit. That is the tailings spigot location will be swapped when the tailings level reaches nominally RL1075 (storage capacity



approximately 200,000m3). The tailings will cascade over slightly weathered and fresh rock benches to the floor of the pit.

(ii) Keeping the supernatant pond to a minimum size will have the effect of minimising

evaporation from the surface of the pond and hence will assist in optimizing the water recovery and tailings density.

(iii) The original pit dewatering bores, where still accessible, and monitoring bores

adjacent to the pit will be utilised as monitoring / recovery bores, as appropriate.

Water samples will be taken every three (3) months from monitoring bores for the pit to check water quality, with water levels in the monitoring bores being read on a monthly basis.

(iv) Towards the end of the life of the pit, the facility should have adequate freeboard

available (total freeboard 0.68m) to store the design rainfall event being that of a 1 in 100 year average recurrence interval (ARI), 72 hour storm event (180mm).

(v) On decommissioning, the tailings facility will remain as a permanent feature of the

landscape. It will consolidate to an increasingly stable mass. Settlement of the upper surface will occur as the tailings consolidate and is likely to be in the order of 1m. This settlement will increase the freeboard capacity of the structure. The actual settlement at any point within the pit will vary dependent on the thickness of tailings and the tailings filling rate of the pit. Section 14.0 contains brief details of the proposed rehabilitation plan.

(vi) Pipelines to and from the RAV 8 Pit will have bunding to prevent spillage of tailings

or return water into the surrounding area in the event of pipeline failure.

5.1 Drawings The following drawings which are presented in Attachment 2 are based on the mine grid and were prepared from data provided by Scott Williams (Surveyor for Tectonic Resources NL). RAV 8 Pit Tailings Storage Facility Drawing No. 5720/03/01 General Arrangement Monitoring Bore, Typical Details Sketch 5.2 Construction Method



Construction will include installation of pipelines for tailings delivery and return water, pipeline bunding and associated sumps, and establishment of monitoring / recovery bores (refer to Attachment 2 for drawings/sketches). 5.3 Area The final surface area of inpit tailings facility, after deposition of tailings, to a nominal level of RL1157m will be approximately 8.27 ha. For the purposes of setting bonds the R8TSF has a surface area of 8.27ha. 5.4 Depth The maximum depth of the pit is approximately 125 m and the underground workings extend to a depth of 200m below the base of the pit. Based on a tailings production of 2.4 Mt and assuming an insitu (dry) density of 1.5t/m3, the estimated tailings depth is approximately 102m (filling to RL1130m nominal). 5.5 Capacity The capacity of the pit to RL 1157m is approximately 3.3 x 106 m3, allowing for an ‘operational’ freeboard allowance of 300mm. A depth capacity curve for the pit is presented as Figure 4. 5.6 Wall Angles Overall pit slope angles are estimated to vary between 30o on the north and west sides of the pit where the main pit ramp is located to 47o on the eastern side of the pit. 5.7 Water Recovery System Surface water liberated from the tailings slurry will be recovered from the impoundment area via a pontoon mounted pump. The original pit dewatering bores, where still accessible, and monitoring bores could be utilised as recovery bores, if required. The option of installing an underdrainage within the underground workings has been examined. The decision not to proceed with construction of such a facility was based on the following factors:

(i) The ore body is relatively flat dipping and the method of underground mining within the narrow orebody with a limited number of drives has precluded the use of filters as was



achieved at the Angew Mine (Redeemer Pit Tailings Storage Facility). The main drives which provide opportunities for filter construction are relatively high within the workings, only just below the proposed tailings discharge point, and therefore the benefits of the underdrainage system were limited.

(ii) The water inflows to the workings, currently 10 l/sec, the nature of the flat dipping orebody

and mining methods give limited scope for the tailings slurry reach an average dry density of much more than 1.0 t/m3.

(iii) The storage volume within the underground workings is very small in comparison to the

total volume of the pit Preliminary estimates of settlement for the surface of the tailings for a pit of 120m depth and assuming filling over a 6 year period have been undertaken and these analyses show negligible difference in the final surface settlement, less than 1.0m, with and without the underdrainage. 5.8 Liners The tailings storage design does not incorporate any artificial liners within the pit. 6.0 TAILINGS DEPOSITION METHOD Tailings placement is by single point spigot discharge, with tailings initially deposited into the underground workings as described in Section 4.1. Tailings will be deposited subaerially. A detailed description of the operating procedures is included in the operations manual presented as Attachment 3. 7.0 MONITORING In addition to the water level and groundwater monitoring, detailed in Section 11.0, daily inspections of the pit rim and access ramp will be undertaken during the operations of the inpit tailings storage to monitor for any signs of distress that may lead to wall instability. 8.0 GEOTECHNICAL INVESTIGATIONS The Geotechnical Assessment for this project comprised a desktop study of information provided by Tectonic Resources NL which was supplemented by an inspection of the pit. The Geotechnical Assessment is included in the document titled ‘RAV 8 Pit, Tailings Storage Facility, Geotechnical Assessment, RAV 8 Mine’, presented as Attachment 1. The design concept adopted for this tailings facility was formulated to meet both the general requirements of the mine, the general parameters discussed in the previous sections and is based on a review of existing similar, inpit type tailings storage facilities at the following locations:



• Redeemer Pit Agnew. • Fisher Pit Jundee. • Perch, Perch North and Perch West Pits Plutonic Gold Mine, near Meekatharra. • South Bounty and East Bounty Pits Bounty Gold Mine, Forrestania. • HP and Carolyn Pits Lawlers Gold Mine, near Leinster. • Venture Pit, Central Norseman Gold Corporation. • Gwendolyn Pit, Herbert Mining, Diemals. • K1 Pit, Marymia Gold Operation, Meekatharra. • K1SE Pit, Marymia Gold Operation Meekatharra.

The geotechnical assessment of the existing pit indicates the storage can be operated safely, provided operational guidelines are followed. It is anticipated that some minor pit wall failures may occur during the operation of the tailings storage facility, however these minor failures are unlikely to effect the operation of the decant system or the access ramp, and are unlikely to pose a risk to personnel servicing pumps etc. A major deep seated pit wall failure which may extend beyond the pit perimeter is not anticipated. It will be necessary however for personnel to monitor the walls and pit rims for any signs of distress that may indicate a possible failure mechanism, particularly the southern wall approximately 100m from the South Coast Highway. It should be noted that there was a DoIR requirement that a buttress be formed at the toe of the southern wall of the pit with 50,000m3 of waste prior to the mine being closed. With the proposed tailings deposition into the pit, the DoIR requirement will effectively be superseded, as the tailings will form a much larger buttress. 9.0 OPERATING PROCEDURES An operations manual titled, ‘RAV 8 Pit, Tailings Storage Facility, Operations Manual, RAV 8 Mine’, presented as Attachment 3, provides a description of the operating procedures to achieve the design objectives. 10.0 GEOCHEMICAL CHARACTERISATION Geochemical characterisation testwork was undertaken under the direction of Graeme Campbell & Associates (GCA). The results of the testwork indicate that the ‘oxide’ ores from the Trilogy and Kundip Pits are Non Acid Forming (NAF) and the ‘primary’ ore from the Kundip Pit should be classified as Potentially Acid Forming – [Long Lag] (PAF-[Long Lag]). The testwork also indicates that the ores are variously enriched in an array of elements (refer to Section 3.0). The covering of the tailings solids with water during deposition will reduce the impact of PAF materials and exposure to sunlight will result in volatilization (disassociation) of cyanide. The GCA geochemical assessment report is presented in Attachment 4 and the recommendations for an oxide capping of the TSF in the GCA report have been adopted. 11.0 INSTRUMENTATION



It is planned to monitor the existing monitoring/mine dewatering bores around the RAV 8 Pit. These existing bores will be supplemented with 3 new monitoring/recovery bores, located by the Project Hydrogeologist in order to target geological structures/shears. Water samples will be taken every three (3) months from the monitoring bores located around the RAV 8 Pit to check water quality as per the requirements stipulated by the DoE. Water levels however will be read on a monthly basis. 12.0 TAILINGS PROPERTIES

• Average slurry density ex-plant 40% solids • Final tailings density (average) 1.50 dry t/m3 ( average dry density) • Angle of internal friction 28o and 340 • Particle size distribution 80% passing 75µm • Hydraulic Conductivity (estimated) 10-7 to 10-9 m/s

13.0 EMERGENCY ACTION PLAN An emergency action plan is included in the operations manual presented as Attachment 3. 14.0 REHABILITATION A tailings deposition strategy will be adopted such that some ‘oxide’ ore will be stockpiled (or mined) and processed after the processing of the PAF-[Long Lag] Kundip ‘primary’ ore. The final tailings surface will therefore be NAF and the facility will be capped with mine waste from the surrounding dumps. Environmental management and rehabilitation plans to be implemented at the completion of filling include: (i) Monitor the level of the tailings surface following the completion of the last tailings

deposition cycle. (ii) Monitor the formation of the crust following the completion of the last tailings cycle,

prior to the deposition of new tailings as part of the ‘topping up’ process. This monitoring may comprise moisture and density monitoring as well as shear strength testing as appropriate.

(iii) Once topping up has been completed and little further settlement is expected, the top

surface of the storage will capped with a layer of mine waste (1m to 2m nominal thickness) in order to minimise the ingress of rainfall into the tailings, dust generation from the dried tailings surface and support topsoil / a ‘growth’ medium for re-vegetation of the top surface.

The rehabilitation concept is presented as Figure 5. Rehabilitation/decommissioning plans will be produced by Tectonic Resources NL and submitted to the DoIR near the end of the life of the facility.



15.0 REFERENCES

1. Department of Industry and Resources document titled, ‘Guidelines on the Safe Design and Operating Standards for Tailings Storage’, dated May 1999.

2. Department of Industry and Resources document titled, ‘Guidelines to help you get

Environmental Approval for Mining Projects in Western Australia’, dated March 1998.

3. Rockwater Proprietary Limited, ‘RAV 8 Nickel Mine, Ravensthorpe, Groundwater Production/Monitoring Summary, June 2002 to May 2003,’ dated November 2003 (report no.253.0/03/05).

4. Peter O’Bryan & Associates, various geotechnical reports and in particular letters dated

December 2000 and July 2001.



TABLE OF CONTENTS Page no.

1.0 INTRODUCTION 1 1.1 Location 2

1.2 Ownership 2

1.3 Existing Facilities 2

2.0 GENERAL INFORMATION 3 2.1 Process Type 3

2.2 Rated Throughput 3

2.3 Ore Type 3

2.4 Tailings Production 4

3.0 TAILINGS PROPERTIES 4 3.1 Mineralogy 4

3.2 Residual Process Chemicals 4

4.0 SITE SELECTION 5 4.1 Background 5

4.2 Climate 5

4.3 Landform and Soils 6

4.4 Geology 6

4.5 Hydrogeology 6

4.6 Hydrological Characteristics 7 4.6.1 Surface Water 7 4.6.2 Design Floods 7

5.0 TAILINGS STORAGE FACILITY STRUCTURE 7

5.1 Drawings 8

5.2 Construction Method 8

5.3 Area 9

5.4 Depth 9

5.5 Capacity 9

5.6 Wall Angles 9



5.7 Water Recovery System 9

5.8 Liners 10

6.0 TAILINGS DEPOSITION METHOD 10

7.0 MONITORING 10

8.0 GEOTECHNICAL INVESTIGATIONS 10

9.0 OPERATING PROCEDURES 11

10.0 GEOCHEMICAL CHARACTERISATION 11

11.0 INSTRUMENTATION 11

12.0 TAILINGS PROPERTIES 12

13.0 EMERGENCY ACTION PLAN 12

14.0 REHABILITATION 12

15.0 REFERENCES 13

LIST OF FIGURES AND APPENDIXS (behind text) Tailings Storage Data Sheet and Explanatory Notes FIGURES 1 and 2 Tenement Location Plan FIGURE 3 Depth Capacity Curve for the Storage Facility FIGURE 4 Rehabilitation Concept FIGURE 5 Geotechnical Assessment of the Pit ATTACHMENT 1 Drawings ATTACHMENT 2 Operations Manual ATTACHMENT 3 Geochemical Assessment Report ATTACHMENT 4

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Project no: PS5720.03 17 June, 2005 Our ref: PS5720.03 AA inpitnoi Rev A Tectonic Resources N.L. Suite 4, 100 Hay Street SUBIACO WA 6902 Attention: Ms Kim Bennett Dear Kim RE: RAV 8 INPIT TAILINGS STORAGE FACILITY NOTICE OF INTENT DOCUMENTATION Please find attached three (3) bound copies and six (6) unbound copies of the Notice of Intent (NOI) for the above project. It is understood that you will distribute copies of this document to the various government departments for regulatory approvals. Please note that unbound copies of the Executive Summary only, have also been provided to you, for your distribution to the Local Shire and Local Pastoralist. We trust this information meets your immediate requirements. Should you require clarification of any information, please do not hesitate to contact Soil and Rock Engineering Pty Ltd for technical details of the design. Yours faithfully for and on behalf of SOIL & ROCK ENGINEERING Christopher Lane REGIONAL MANAGER Distribution: Tectonic Resources NL 3 Copies.


TAILINGS STORAGE DATA SHEET RAV 8 INPIT TSF

Job No.: PS5720.03 Please answer all questions, with separate sheets for cells of different ages. Ref No.: ps5720.03 AA inpitnoi Rev A 1. PROJECT DATA

1.1 Project Name: RAV 8 Mine 1.2 Date: March 2004 1.3 TSF name: R8TSF 1.4 Commodity: Gold and Polymetallic Minerals 1.5 Name of data provider:* Kim Bennett Phone:* 9388 3872 1.6 TSF centre co-ordinates (AMG): 6,278,285m North 249,440m East 1.7 Lease numbers: M74/13 2. TSF DATA

2.1 TSF Status: Proposed X 2.2 Type of TSF:1 Inpit 2.2.1 Number of cells:2 1

2.3 Hazard rating:3 Low 2.4 TSF category:4 3

2.5 Catchment area:5 9ha 2.6 Nearest watercourse: Bandalup Creek

2.7 Date deposition started (mm/yy): N/A 2.7.1 Date deposition completed (mm/yy): N/A 2.8 Tailings discharge method:6 Single Spigot 2.8.1 Water recovery method:7 pontoon pump

2.9 Bottom of facility sealed or lined? No 2.9.1 Type of seal or liner:8 N/A

2.10 Depth to original groundwater level: 20–30m 2.10.1 Original groundwater TDS: 20,000/25,000mg/L 2.11 Ore process:9 Floatation CIP/CIL 2.12 Material storage rate:10 0.4-0.8 tpa

2.13 Impoundment volume (present): 0 x 106m3 2.13.1 Expected maximum: 1.6 x 106m3 2.14 Mass of solids stored (present): 0 x 106 t 2.14.1 Expected maximum: 2.4 x 106 tonnes 3. ABOVE GROUND FACILITIES

3.1 Foundation soils: N/A 3.1.1 Foundation rocks: N/A 3.2 Starter bund construction materials:11 N/A 3.2.1 Wall lifting by:12 N/A 3.3 Wall construction by: mechanically hydraulically

3.3.1 Wall lifting material:13 N/A.

3.4 Present maximum wall height agl:14 N/Am 3.4.1 Expected maximum: N/Am 3.5 Crest length (present): N/A 3.5.1 Expected maximum: N/Am 3.6 Impoundment area (present): N/Aha 3.6.1 Expected maximum: N/Aha 4. BELOW GROUND / IN-PIT FACILITIES

4.1 Initial pit depth (maximum): 125m 4.2 Area of pit base: 0.02ha 4.3 Thickness of tailings (present): 0m 4.3.4 Expected maximum: 102m 4.4 Current surface area of tailings: 0ha 4.5 Final surface area of tailings: 8.27ha 5 PROPERTIES OF TAILINGS

5.1 TDS: 25,000-30,000mg/L

5.2 pH:8.4-8.7 5.3 Solids content: 40% 5.4 Deposited density: 1.5t/m3

5.6 WAD CN: <50mg/L 5.7 Total CN: 300mg/L 5.5 Potentially hazardous substances:15

5.8 Any other NPI listed substances in the TSF?:16..

Not to be recorded in the database; for 1, 2, 3 etc see explanatory notes on the next page.


EXPLANATORY NOTES FOR COMPLETING TAILINGS STORAGE DATA SHEET The following notes are provided to assist the proponent to complete the tailings storage data sheet. 1. Paddock (ring-dyke), cross-valley, side-hill, in-pit, depression, waste fill etc. 2. Number of cells operated using the same decant arrangement. 3. See Table 1 in the Guidelines. 4. See Figure 1 in the Guidelines 5. Internal for paddock (ring-dyke) type, internal plus external catchment for other facilities. 6. End of pipe (fixed), end of pipe (movable), single spigot, multi-spigots, cyclone, CTD (Central Thickened

Discharge) etc. 7. Gravity feed decant, pumped decant, floating pump etc. 8. Clay, synthetic etc. 9. See list below for ore process method. 10. Tonnes of solids per year 11. Record only the main material(s) used for construction eg: clay, sand, silt, gravel, laterite, fresh rock,

weathered rock, tailings, clayey sand, clayey gravel, sandy clay, silty clay, gravelly clay, etc or any combination of these materials.

12. Wall lifting method during the reporting period, if raised. 13. If the wall has been raised during the reporting period, the wall lifting material used. Is it tailings or any

other (or combination of) material(s) listed under item 11 above. 14. Maximum wall height above the ground level (not AHD or RL). 15. Arsenic, Asbestos, Caustic soda, Copper sulphide, Cyanide, Iron sulphide, Lead, Mercury, Nickel

sulphide, Sulphuric acid, Xanthates etc. 16. NPI – National Pollution Inventory. Contact Dept of Environmental Protection for information on NPI

listed substances.

ORE PROCESS METHODS The ore process methods may be recorded as follows: Atmospheric Acid Leaching Atmospheric Alkali Leaching

Bayer process Becher process

BIOX CIL/CIP

Crushing and screening Flotation

Gravity separation Heap Leaching

Magnetic separation Ore sorters

Pressure Acid leaching Pressure Alkali leaching

Pyromet SX/EW (Solvent Extraction/Electro Wining)

Vat leaching Washing and screening


RAV 8 PIT TAILINGS STORAGE FACILITY

NOTICE OF INTENT RAV 8 MINE

Report prepared for: TECTONIC RESOURCES NL SUITE 4 100 HAY STREET SUBIACO WA 6902 Report prepared by: SOIL & ROCK ENGINEERING (A Division of Coffey Geosciences Pty Ltd) PO BOX 1530 OSBORNE PARK WA 6916 Ref: PS5720.03 AA inpitnoi Rev 0 Date: 17 June, 2005

Ref: PS5720.03 AA inpitnoi Rev 0


RAV 8 PIT TAILINGS

STORAGE FACILITY

RAV 8 MINE

NOTICE OF

INTENT

for

TECTONIC RESOURCES

NL

PS5720.03

17 June, 2005

tailings storage facility – rav 8 pit tectonic …

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