MANCALA RESOURCES PTY LTD NOTICE OF INTENT Burns Peak ...epa.tas.gov.au/documents/mancala resources pty ltd... · mining is the trenches or mini open cuts plus adits or tunnels. The

MANCALA RESOURCES PTY LTD NOTICE OF INTENT Burns Peak Operation

September 2012

This Notice of Intent was prepared by: CALOUNDRA ENVIRONMENTAL PTY LTD P O Box 242 Golden Beach Qld 4551 Contact: Stephen Kent Telephone: 07 5439 7877 Mobile 0417 574 799 E mail [email protected] in conjunction with: Mancala Resources Pty Ltd Launceston, Tasmania 7250 Postal Address PO Box 240 Launceston, Tasmania 7250 Contact: Tim Akerman Business Development Manager Telephone: 03 6334 7034 Mobile: 0419 138 251 Email: [email protected] Website: http://www.mancala.com.au The NOI will be submitted to: The Chairperson Board of Environmental Management and Pollution Control Tasmanian Environment Protection Authority GPO Box 1751 Hobart TAS 7001

LIMITATIONS OF REPORT

Purpose of Report

Caloundra Environmental Pty Ltd ("Caloundra Environmental") has prepared this document titled “Mancala Resources Pty Ltd, Notice of Intent, Burns Peak Operation" (the “Report”) for the use of Mancala Resources Pty Ltd ("the “Client”).

Limitations of Report

The Report must be read in light of:

the readership and purposes for which it was intended;

its reliance upon information provided to Caloundra Environmental by the Client and others which has not been verified by Caloundra Environmental and over which it had no control;

the limitations and assumptions referred to throughout the Report;

the cost and other constraints imposed on the Report; and

other relevant issues which are not within the scope of the Report.

Care Taken by Caloundra Environmental

Subject to any contrary agreement between Caloundra Environmental and the Client:

Caloundra Environmental makes no warranty or representation to the Client or third parties (express or implied) in respect of the Report, particularly with regard to any commercial investment decision made on the basis of the Report; and

use of the Report by the Client or third parties shall be at their own risk.

TableofContents

INTRODUCTION .................................................................................................................. 7

The Proponent ........................................................................................................................................................... 7

Scope and History of the Proposal .............................................................................................................................. 7 Timber extraction ............................................................................................................................................................. 7 Mining .............................................................................................................................................................................. 8

Development Timeframe ......................................................................................................................................... 10

Mineral Resource and Mining Plan ........................................................................................................................... 11 Costean Lode .................................................................................................................................................................. 12 Southern Trenches Deeps .............................................................................................................................................. 12 Browns Tunnel ............................................................................................................................................................... 13 Land Tenure ................................................................................................................................................................... 13

Legislative Approval ................................................................................................................................................. 15 Commonwealth Assessment Process ............................................................................................................................ 15 Environmental Management Plans ................................................................................................................................ 15 Relevant Legislation, Regulations, Codes and Policies ................................................................................................... 15 Environmental Policy ..................................................................................................................................................... 16

Mancala Sustainable Development and Environmental Policy ................................................................................. 17

SITE DESCRIPTION AND EXISTING ENVIRONMENT .................................................... 18

Location of Site, Land Use and Tenure ...................................................................................................................... 18

Terrestrial Environment ........................................................................................................................................... 19 Meteorology .................................................................................................................................................................. 19 Flora ............................................................................................................................................................................... 19 Fauna .............................................................................................................................................................................. 20 Geological Setting .......................................................................................................................................................... 22

Heritage .................................................................................................................................................................. 22

Aquatic Environment ............................................................................................................................................... 23 Hydrology ....................................................................................................................................................................... 23 Water Quality ................................................................................................................................................................. 23

PROJECT DESCRIPTION ................................................................................................. 25

Mining plan ............................................................................................................................................................. 25 Costean Lode .................................................................................................................................................................. 25 Southern Trenches ......................................................................................................................................................... 25 Browns Tunnel ............................................................................................................................................................... 26

Haulage of Ore ........................................................................................................................................................ 27

MANAGEMENT OF POTENTIAL ENVIRONMENTAL IMPACTS ..................................... 28

Assessment of Environmental Impacts ..................................................................................................................... 28

Risk Assessment ...................................................................................................................................................... 30 Identifying the Hazards .................................................................................................................................................. 30 Risk Ranking ................................................................................................................................................................... 31

Methodology ............................................................................................................................................................ 31 Likelihood of Occurrence. ..................................................................................................................................... 31 Consequence of hazard......................................................................................................................................... 31

Risk Ranking Matrix ........................................................................................................................................................ 32 Hazard Risk Evaluation ................................................................................................................................................... 32 Surface Footprint ........................................................................................................................................................... 33 Waste Rock .................................................................................................................................................................... 35 Mine Water .................................................................................................................................................................... 35 Traffic ............................................................................................................................................................................. 38 Rehabilitation and Closure ............................................................................................................................................. 38

Legacy Environmental Disturbance and ARD ............................................................................................................ 39

Consultation ............................................................................................................................................................ 39

KEY ENVIRONMENTAL ISSUES ...................................................................................... 40

Miscellaneous Environmental Issues ........................................................................................................................ 40

REFERENCES ................................................................................................................... 41

APPENDIX 1 EPBC REFERRAL ....................................................................................... 42

List of Figures

FIGURE 1 ML6M/2012 ................................................................................................................................................ 11 FIGURE 2 BURNS PEAK ‐ OLD WORKINGS ................................................................................................................... 12 FIGURE 3 LAND TENURE ............................................................................................................................................. 14 FIGURE 4 REGIONAL LOCALITY ................................................................................................................................... 18 FIGURE 5 CLIMATIC AVERAGES ‐ HELLYER 1985 TO 1994 ........................................................................................... 19 FIGURE 6 TOPOGRAPHY BURNS PEAK ........................................................................................................................ 24 FIGURE 7 ISOMETRIC VIEW OF ST PIT, PROPOSED PORTAL AND DECLINE/INCLINE DEVELOPMENT ......................... 26 FIGURE 8 BROWNS TUNNEL PIT ................................................................................................................................. 27 FIGURE 9 AERIAL PHOTO SHOWING CURRENT AREAS OF IMPACT ............................................................................ 34 FIGURE 10 SCHEMATIC REPRESENTATION OF WATER MANAGEMENT DURING STAGE 1, COSTEAN LODE ................ 36 FIGURE 11 SCHEMATIC REPRESENTATION OF WATER MANAGEMENT DURING STAGE 2 MINING ............................. 37 FIGURE 12 LAYOUT BROWNS TUNNEL ......................................................................................................................... 37 FIGURE 13 SITE HAULAGE ROUTE ................................................................................................................................. 38

List of Tables

TABLE 1 FAUNA SPECIES OF CONSERVATION SIGNIFICANCE RECORDED ON DPIPWE NATURAL VALUES ATLAS ........ 21 TABLE 2 FAUNA SPECIES OF CONSERVATION SIGNIFICANCE ‐ EPBC PROTECTED MATTERS SEARCH TOOL. ............... 22 TABLE 4 EIS MATRIX ASSESSMENT ............................................................................................................................... 28 TABLE 5 PRELIMINARY RISK ASSESSMENT BURNS PEAK .............................................................................................. 33 TABLE 3 PROPOSED ACTIVITY STAGES AND REMEDIATION WORKS ............................................................................ 39

Burns Peak Operation - Notice of Intent – Mancala July 2012 7

INTRODUCTION

The purpose of this Notice of Intent (NOI) is to describe the proposed operation and identify environmental management issues for the Mancala Resources Pty Ltd (Mancala) Burns Peak Operation and to support an eventual application for a Land Use Permit under the Land Use and Approvals Act (LUPAA). Mancala is currently developing Stage 1 and Stage 2 of the Burns Peak Operation which comprise a small open cut at Costean Lode and an underground operation at Southern Trenches. At Burns Peak, MMG Australia Limited (MMG) is the current holder of EL48/2004, known as the Mt Kershaw Licence. Mancala have entered into a Heads of Agreement which allows Mancala to explore and define resources on the EL and to apply for a depth limited mining lease if the exploration success warrants such. MMG and Mancala, as per the Heads of Agreement, are nearing completion of negotiations in respect to an Ore Sales Agreement which will govern the commercial relationship between the parties for ore production from the proposed ML. This Notice of Intent is provided in sufficient detail to allow the EPA to initially review the project, determine the appropriate level of assessment, and provide the proponent with guidelines by which they can prepare a Development Proposal and Environmental Management Plan to accompany the eventual development application to the Waratah Wynyard Council.

The Proponent

Mancala Resources (ACN 153 561 169), is an Australian Proprietary Company, Limited by Shares. The Mancala Group head office is located in Melbourne Australia, with subsidiary offices in Launceston, Burnie, Bendigo and Sydney. Ownership of the Group is retained by its Directors. Within Tasmania, besides short term mining contracts with the major mines, the Group has conducted seven mining operations in the state, culminating with the Fossey underground mine owned by Bass Metals.

Scope and History of the Proposal

Mancala has a depth limited mining lease over an area of 143 hectares as shown in Figure 1. The area is totally enclosed by Exploration Licence 48/2004 held by MMG Australia Limited. The area has been used in the past for forestry and mining operations.

Timber extraction

Evidence of old logging activity is present and former snigging tracks are evident. Logging is not occurring at present and there are no plans to log the area in the near future. The legacy of this activity is a paucity of large trees and old tracks.


Mining

The site has been subject to moderate mining activities in the vicinity of the “Southern Trenches” and “Browns Tunnel”. This activity took place from around 1899. The legacy of mining is the trenches or mini open cuts plus adits or tunnels. The water draining from the adits and legacy costeans into Strong’s Creek are showing evidence of iron hydroxides, an indicator of acid drainage (Plates 1- 4). Hercules Resources P/L (a wholly owned subsidiary of Mancala P/L) was the holder of ML 20M/2000 at Burns Peak and operated the ML during 2001 producing approximately 14,000 tonnes at 7.9% Pb, 11.9% Zn, 8.9g/t Au and associated copper and silver credits. All production was sourced from a small open cut and hauled to the Pasminco concentrator at Rosebery. Approximately 90,000m3 of overburden was removed and encapsulated within a waste dump. The lease was relinquished in 2005.

Plate 1 Exposed Sulphides on Floor of Costean Trench


Plate 2 Water overflowing Southern Trenches Pit Towards Strong Creek

Plate 3 Exposed sulphides on Surface of Waste Rock Dump


Plate 4 Evidence of ARD from Legacy Waste Rock Dump

Since the early 20th century the Browns Tunnel area has been the site of extensive exploration activity with over 36 diamond drill holes for 7,540m of drilling over a strike extent of only 300m.

Development Timeframe

Construction is expected to commence in early 2013 following environmental approval. Stages 1 & 2 will last between 6 and 11 months. Stage 3 is scheduled to be mined over 16 months but could take as long 24 months for completion after Stages 1 & 2.


Mineral Resource and Mining Plan

The Burns Peak mine is expected to deliver between 30,000 and 50,000 tonnes of lead zinc ore to the existing Rosebery mine's concentrator over a 6 - 33 month period.

Figure 1 ML6M/2012

Mancala is planning to cut back an existing costean trench (Costean Lode Pit) to excavate ore resources left on the floor of the trench (Stage 1) and planning to develop an underground mining operation using stoped and draw techniques to extract remaining ore


resources from the floor of an existing but abandoned open cut mine (Stage 2) at Southern Trenches. The mining operation will necessitate the development of access tracks, a Run of Mine ore stockpile, a portal and small profile decline to develop the stoping operation, a water treatment facility and small holding dam to take metal hydroxide sludges and some remediation of legacy issues at the site A 3rd Stage of the project is planned to exploit remnant ore from the Browns Tunnel area approximately 1 kilometre to the north of the open cut (See Figures 1 - 3). This is expected to be via standard open cut operations using truck and shovel using infrastructure developed for Stages 1 & 2 plus additional access tracks.

Figure 2 Burns Peak - Old Workings

JORC compliant mineral resource estimates have been compiled for the Southern Trenches Deeps and Costean Lode areas based upon recent (2011) drilling and sampling programs.

Costean Lode

Costean Lode is located approximately 120m South West of the Thomas Tunnel portal at 4,920N and 4640E (BPMG – Burns Peak Mine Grid). The mineralisation was located following the discovery of sulphide rubble at the toe of an 1970’s costean. The costean floor was subsequently cleaned with an excavator and some 6.5m of high grade mineralisation was discovered. This was assayed to contain 1.0% Cu, 21.1% Pb, 43.1% Zn, 124g/t Ag and 3.5g/t Au.

Southern Trenches Deeps

Southern Trenches mineralisation was mined via open cut methods in 2001, producing approximately 14,000 tonnes of high grade based metal and gold ore. On closure an ore remnant was known to exist in the pit floor. This mineralisation remained un-mined as the ore was thought to be limited in extent (a vertical DDH significantly limited its down dip projection) and any extraction via open cut would require a significant cut back to the east.


The 2011 drilling program showed the remnant ore steepening in dip and plunging approximately 60m below the current pit floor. The strike extent is limited to approximately 35m.

Browns Tunnel

Browns Tunnel is located at the northern extremity of the Burns Peak area, between 5,200mN and 5,500mN. Browns Tunnel itself, is a small tunnel and associated small open cut driven (in the 1890’s) into the eastern flank of Burns Peak. Some 300 tonnes of 2% Zn, 2g/t Au and 44g/t Ag was reportedly produced from the operation. The complex nature of the geology at Browns Tunnel is evidenced by successive drill programs resulting in diminishing (tonnes and grade) resource estimates. In 1984, 110kt at 25%Pb+Zn was estimated from Browns Tunnel from 5 drill holes. The most recent (1998) resource estimate, based on 24 holes in the same spatial area as the 1984 estimate resulted in some 90kt at 9.5% Pb+Zn.

Land Tenure

Mancala Resource has been granted a depth limited Mining Lease ML6M/2012. On the ML, all land is Crown Land gazetted as State Forest, informal reserves, portions of the Burns Peak and Mt Kershaw Forest Reserves and some HEC reserves. The proposed Mining Lease is contained wholly within the Burns Peak Forest Reserve, part of the CAR Reserve System (Figure 3). The Regional Forest Agreement requires that the area protected in CAR reserves be maintained. Any loss of a Formal Reserve must therefore be replaced by the reservation of an alternative area. The Burns Peak area is contained within the Tarkine area boundary that is currently under assessment for inclusion on the National Heritage List.


Figure 3 Land Tenure


Legislative Approval

As the Burns Peak Operation proposes to extract and process in excess of 1,000 tonnes of ore per annum, Mancala will need to obtain approvals to operate under the Land Use Planning and Approvals Act (LUPA) and the Environmental Management and Pollution Control Act (EMPCA) as a Level 2 activity.

Commonwealth Assessment Process

Under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act), actions that have, or are likely to have, a significant impact on a matter of national environmental significance require approval from the Australian Government Minister for Sustainability, Environment, Water, Population and Communities (SEWPaC). The minister will decide whether assessment and approval is required under the EPBC Act. The proposal was referred to the Australian Department of Sustainability, Environment, Water, Population and Communities (SEWPaC) on 19 June 2012 and was deemed to be a controlled action (See Appendix 1) on 22 August 2012. An agreement exists between the Commonwealth of Australia and the State of Tasmania under Section 45 of the EPBC Act 1999 relating to Environmental Impact Assessment. The agreement provides accreditation for the Tasmanian environmental impact assessment processes in the Environmental Management and Pollution Control Act 1994.

Environmental Management Plans

Mancala will develop environmental management plans for the operation commensurate with the risks inherent in the operation and good environmental practice.

Relevant Legislation, Regulations, Codes and Policies

Mancala operates under and complies with a variety of Acts, regulations, policies and guidelines that are likely to be significant for this development, including:

Mineral Resources Development Act 1995.

Environmental Management and Pollution Control Act 1994 (and associated Policies and Regulations).

Draft Environment Protection Policy (Noise) 2002.

Groundwater Act 1985.

Resource Management and Planning Appeal Tribunal Act 1993 and associated amendments.

State Policy on Water Quality Management 1997.

Threatened Species Protection Act 1995.

Water Management Act 1999 and associated regulations.


Workplace Health and Safety Act 1995.

Aboriginal Relics Act 1975.

Environment Protection and Biodiversity Conservation Act 1999.

National Parks and Wildlife Act 1970.

National Environmental Protections Council (Tasmania) Act 1995.

Forest Practices Act 1985.

Native Forestry Agreement Act 1980.

Historical Cultural Heritage Act 1995.

Weed Management Act 1999.

Land Use Planning Act 1993

Native Title (Tasmania) Act 1994.

Local Government (Building and Miscellaneous Provisions) Act 1993.

Crown Land Act 1976.

There are no known proceedings standing against Mancala under any Commonwealth, State or Territory law regarding the protection of the environment or the conservation, and sustainable use of natural resources in the Project area.

Environmental Policy

Mancala’s Environmental Policy forms part of its Corporate Governance. The relevant environmental section is provided below.


Mancala Sustainable Development and Environmental Policy

The Board and Management of The Mancala Group (Mancala) are committed to the principles of sustainable development. We see the environment as an opportunity for economic growth and business success while acknowledging that all of our activities must be balanced with protection of the environment. To achieve the standards of environmental performance to which it is committed, Mancala shall provide both adequate financial and human resources which shall endeavour to ensure the following:

• Conducts operations, as a minimum, in compliance with all relevant environmental codes of practice, licences and legislation;

• Identifies monitors and manages environmental risks arising from its operations; • Seeks continuous performance improvement in environmental management,

production processes, waste management and the use of resources; • Sets and periodically reviews objectives and targets which relate to

environmental management; • Provides appropriate training and awareness for all employees on environmental

issues; • Communicates regularly with employees about its aim and about the

responsibilities of individuals; and • Communicates with shareholders and the community about its environmental

performance and contributes to the development of laws and regulations which may affect our business.

The acceptance and development of an environmentally responsible culture is to be promoted at all locations and environmental awareness is to be included as a major component in the induction of personnel at all sites, including the corporate head office. An integral process through all phases of Mancala’s mining and contracting activities is the assessment and control of environmental impacts. ……………………………….. ………………………………….. M.P Kyne Executive Director F.W.Lannen Executive Director


SITE DESCRIPTION AND EXISTING ENVIRONMENT

Location of Site, Land Use and Tenure

The Burns Peak project is located approximately 6 km northwest of the township of Tullah and to the north of Lake Rosebery. The site is within the municipality of Waratah-Wynyard. (Figure 4)

Figure 4 Regional Locality


Terrestrial Environment

The proposed Burns Peak Operation is located within the Burns Peak Forest Reserve, on the west coast of Tasmania. It is located approximately nine kilometres to the north-east of Tullah within the Tasmanian West bioregion. It is currently accessed via Boco Road from the Murchison Highway. The topography can be summarised as comprising the lower south-western slope of Burns Peak and other associated hills and valleys running off this feature. The eastern section is higher ground leading up to Burns Peak, while the western section drops away to lower lying valleys that are dissected by upper level drainage lines. North Barker Ecosystem Services undertook a flora and fauna habitat assessment in March 2012 to assess the natural values of the study area.

Meteorology

The climate of the Burns Peak area is characterised by cool temperatures and high annual rainfall averaging 1981mm per year. Rainfall exceeds evaporation by more than 4:1 with no months where evaporation exceeds rainfall. Average monthly rainfall figures for the Hellyer site (some 17 kilometres to the north-east) exhibit a range from approximately 85mm in February to 270mm in August. The mean maximum temperature ranges from 29oC in January to 11oC in July.

Figure 5 Climatic averages - Hellyer 1985 to 1994

Flora

The vegetation on site has a history of disturbance from both logging and mining activities. Disturbance appears to be both historical from the original mine that operated on site and


also some areas appear to have been logged and are in a regrowth stage. Historic mining activities have left on site more obvious disturbance associated with quarry areas, access roadways and a large waste rock dump. Acid drainage from the previous mining activities has killed some small areas of low-lying heathland. Recent disturbance from the current exploration activities is also significant and takes the form of roads, exploration tracks, cut lines and drilling platform areas. The vegetation in the study area is variable but can be summarised in the following way. Most of the study area is composed of Eucalyptus nitida forest over Leptospermum (WNL) and associated Buttongrass moorland with emergent shrubs (MBS) and Melaleuca squamea heathland (SMM) on the poorer soils, in terms of nutrient levels and/or drainage. Melaleuca squamea heathland (SMM) occurs on the lower lying areas within the study area. In areas of better quality soils taller forest occurs, including Eucalyptus obliqua forest with broad-leaf shrubs (WOB), Eucalyptus obliqua forest over rainforest (WOR), Eucalyptus nitida forest over rainforest (WNR) and Nothofagus - Atherosperma rainforest (RMT). None of the vegetation communities recorded are listed as threatened under the Tasmanian Nature Conservation Act 1995.

Fauna

The area contains a range of fauna habitats including rainforest, eucalypt forest, heathland, buttongrass moorland and the aquatic environments of the minor creeklines. The altitudinal range is from approximately 370m asl in the south-west to 550 m asl in the north-east. The complex structure of the habitat on site provides suitable habitat for a range of bush birds and mammals. In terms of wedge-tailed eagles, the area contains suitable vegetation, in the form of large old trees capable of supporting a nest which are located in suitably sheltered areas. Consequently the overall area is suitable for breeding. However the available habitat is considered low quality, because the vegetation type suggests that prey availability would be low. Eight threatened fauna species have been recorded in the Natural Values Atlas (DPIPWE database, Tasmania) within a 5 km radius of the area or are considered to have the potential to occur because of the presence of suitable habitat. Table 1 lists all threatened fauna species and gives a brief discussion to indicate if there is suitable habitat present.


Table 1 Fauna Species of Conservation Significance recorded on DPIPWE Natural Values Atlas

Status

EPBCA

Occurs along the forested margins of major river systems. It usually occurs in shady and often overhanging vegetation of riverine forests dominated by w et

sclerophyll and mixed forest supporting mainly eucalypt species[4]. It is historically also know n from eastern Tasmania. No know n nest sites or records

occur w ithin 5km of the study area.Suitable habitat consists of slow moving water, typical of larger rivers, and banks composed of sediments for nesting in. No suitable habitat

occurs within the study area.

Endangered/

tasmanian wedge-tailed eagle

Require large eucalypt trees in sheltered locations for nesting and are highly sensitive to disturbance during the breeding season. No nest

site records of this species have been recorded within 5km of the study area.

Aquila audax subsp. fleayi ENDANGERED

A wedge-tailed eagle nest survey carried out on 27th July 2011 failed to find any nests, however the area was considered to contain suitable nesting trees. The habitat within the study area was considered to

contain low quality eagle habitat21. This is partly related to the habitat type which suggests that prey availability will be low.

The study area is therefore most likely to be part of a larger foraging territory, but has a low likelihood of being used for breeding.

tasmanian masked owl

Preferred habitat is lowland dry forest and woodland, with nesting occurring in old growth eucalypts with large main stem hollows. The

study area is outside of the core range for this species. No known nest sites or records occur within 5km of the study area.

Tyto novaehollandiae castanops VULNERABLE

The wet vegetation types within the study area are considered to be sub optimal habitat. Due to past disturbance from mining and logging

activities it is considered likely that most of the eucalypts that would have contained large enough hollows to be suitable would have

already been removed. VERY LOW

swift parrot Lathamus discolorVERY LOW – only

as fly overRequires tree hollows for nesting and feeds on nectar of blue gum (E. globulus ) and black gum (E. ovata ) flowers. No records of this species

LOW

SpeciesLikelihood of

occurrence[1] Preferred Habitat[2] and Observations[3]

BIRDS

tasmanian azure kingfisher Ceyx azurea diemenensis ENDANGERED NIL

spotted-tailed quoll

This naturally rare forest-dweller most commonly inhabits rainforest, wet forest and blackwood swamp forest. It forages and hunts on

farmland and pasture, travelling up to 20 km at night, and shelters in logs, rocks or thick vegetation. One record of this species has been

recorded from within 5km of the study area.

Dasyurus maculatus ssp. maculatus VULNERABLE

The study area is highly likely to be within the home range of resident quolls; however, the location is outside the core range of northern

lowland habitat. No scats were observed in the study area.

tasmanian devil

Inhabits a range of forest types, usually within extensive tracts of remnant native vegetation. Seven records of this species have been

recorded within 5km of the study area.

Sarcophilus harrisii ENDANGERED

The study area is highly likely to be within the home range of resident devils and several devil scats and latrine sites were found during this

survey.

MAMMALS

HIGH

HIGH


Table 2 Fauna Species of Conservation Significance - EPBC Protected Matters Search Tool.

Geological Setting

The proposed mining lease is located in the northern portion of the Mt Read Volcanics approximately 10km north of Rosebery (Figure 4). The stratigraphic sequence in the Pinnacles area is analogous to the sequence exposed in and around the Rosebery Mine. The prospects are hosted by the Browns Tunnel Formation, a complex suite of volcaniclastics, interbedded sediments, dacitic and andesitic intrusives. The Browns Tunnel Formation can be broadly correlated with the upper portion of the Central Volcanics Sequence, which at this location, is overlain by the Pinnacles Rhyolite and the White Spur Formation (Southwell Subgroup). Interbedded within the lower portions of and underlying the Browns Tunnel Formation is the feldspar phryic dacitic pumice breccia and dacite lava/intrusives of the Central Volcanic Sequence. At Southern Trenches, both the hanging wall and footwall of the host rocks are pumice breccias while further north at Thomas’s Tunnel dacitic tuffs and andesite form the hanging wall sequence. Further north at Browns Tunnel, the Thomas’s Tunnel hanging wall sequence becomes the footwall sequence.

Heritage

There is no evidence of an Aboriginal presence or artefacts on the project area. Even though there has been old logging and mining in the past, apart from old tracks and two adits, there is no other evidence of this European heritage in the form of machinery, housing, bottles or other artefacts.

Species StatusLikelihood of

occurrence[1] Preferred Habitat[2] and Observations[3]

Australasian bitternBotaurus poiciloptilus

fork-tailed swiftApus pacificus

great egret, white egretArdea alba

cattle egretArdea ib is

white-throated needletail

It is an entirely aerial species occurring between 1 m and 100 m above the ground. It occurs throughout Tasmania for a brief period at the southern most point of its annual migration between February and

March. It is predominantly an aerial species and is not associated with any particular habitat..

Hirundapus caudacutus Could occur in the study area; however no direct impact is anticipated.

Australian grayling Prototroctes maraena Vulnerable NONE

Inhabits the middle and lower reaches of rivers and streams that open to the sea. No suitable habitat occurs within the study area.

FISH

Migratory/ Marine NIL Not a forest or moorland species.

Migratory/ Marine NILLatham’s snipe, Japanese

snipe Migratory/ Marine NILOccurs through out Tasmania and occupies a variety of habitats including swamps, wet grasslands and freshwater or brackish

Migratory/ Marine NILAerial species, no terrestrial habitat in the study area. Predominantly

coastal in Tasmania. Feeds on insects rising in unstable air.

Migratory/ Marine NIL Not a forest or moorland species.

BIRDS

Endangered NILThe Australasian bittern occurs mainly in densely vegetated freshwater wetlands and, rarely, in estuaries or tidal wetlands. No suitable habitat


Aquatic Environment

Hydrology

The relief runs from east to west and precipitation falling on the site currently is shed into Strong’s Creek which runs into the Marionaok River to the west of the site (Figure 6). Although to date no specific hydrological studies have been undertaken in and around the proposed open cut mine workings, water ingress is not anticipated to be significant as:

The existing costean (3.0m depth) shows no evidence of near surface water inflows, especially at its western terminus where it approaches the level of the heath plane;

Resource drilling showed consistent water return suggesting the deeply weathered and oxidised pumice breccia host rocks have a significant clay component preventing water loss; and

On completion of drilling, drill holes do not “make” water and have standing water at approximately 5.0m below surface.

Water Quality

Baseline surface water sampling has commenced on site. Figure 6 shows the location of rivers and creeks, existing tracks and initial surface water sample sites. The initial results indicate the presence of acid rock drainage from the legacies of mining and exploration (costeans, pits, waste rock dumps). Water drainage from the Costean Lode is influenced by the exposed sulphides on the costean floor with pH <5,Total Al > 1000µg/L, Total Zn > 300µg/L and Total Fe 1000µg/L. Water draining from the Southern Trenches open cut has concentrations of Total Cu between 64 and 400µg/L, Total Pb > 1000µg/L, Total Fe > 7000µg/L and with a pH <4.


Figure 6 Topography Burns Peak


PROJECT DESCRIPTION

Mining plan

Conceptually, the Burns Peak Operation will consist of three stages: 1. Open cut mining of the Costean Lode; 2. Underground development and extraction of the Southern Trenches deeps

mineralisation along with further resource definition drilling and mine planning on the Browns Tunnel/Thomas’s Tunnel areas.

3. Open cut mining in the Browns Tunnel area. The proposed stages differ extensively in their infrastructure requirements, operational procedures and manning levels however all are inherently limited in their production profile by the commercial arrangements with MMG (200 tonnes ore per week day). The proposal is a small scale mining operation. The site will operate on a 5 days/week, single day shift basis with preventative maintenance taking place on a weekend. Nominally 10 hour days will be worked by the employees. For Stage 1 a total operating period of 14 weeks is scheduled from site infrastructure preparatory works to placement of the compacted clay impoundment wall in the pit access ramp. Final rehabilitation and closure activities add 4 weeks to the schedule. Actual ore and waste mining activity will occur over a 9 week period. Two months of production drilling/blasting and underground haulage from Stage 2 is scheduled. Ideally Stage 1 and 2 operations would take place over the drier summer months. The 2012/13 summer is targeted for the activity. Stage 3 will follow Stages 1 and 2 with the supporting infrastructure in place for these stages to be used for Stage 3.

Costean Lode

Costean Lode is a small near surface high grade pod of mineralisation which will be extracted via open cut methods. Mineralisation extends to a depth of 20m below surface or 18m below the floor of the costean. A seven metre strike dimension has been conservatively defined by drilling. The proposed pit will be developed by effectively enlarging the existing costean to form a 1:100 upward sloping ramp to the east and developing a semi-circular pit over the ore zone. The pit will be developed to a 17m depth with a 3.0m deep “farewell” cut in the floor. Overall the pit will be 17m deep, 40m in extent north south and 140m east/west (including the ramp access). This will involve mining of 22,850 BCM of ore, overburden and waste rock.

Southern Trenches

The Southern Trenches mineralisation was subject to open cut mining activity in 2001. This resulted in a 55m deep pit excavated into the flank of Burns Peak. A small underground mine is proposed to extraction the remnant ore from the available resource.


Access to the resource will be afforded by a small (3.0 wide x 4.0m high) decline of some 320 metres in length to the mines lowermost level (340mRL). The decline will commence at a portal location to the south west of the pit. The site selected is preferred because:

It minimises the total decline length; Surface topography favours the site i.e. an extensive box cut or similar is not

required; Access to the site is largely via an existing roadway, albeit heavily overgrown; and On closure a low head plug can be easily constructed

At a point some 120 metres down the decline, an incline will be developed to access the midpoint of the ore body, while the decline continues to the low point (Figure 7) The resource base for ST Deeps has been detailed in section 8.2, consisting of 23,000 tonnes at 16.6% Pb+ Zn.

Figure 7 Isometric view of ST Pit, proposed portal and decline/incline development

Browns Tunnel

Browns Tunnel will consist of an open cut pit some 80 metres deep as shown in Figure 8. The pit will excavate a total of 613,156 M3 of material of which 18,878 M3 will be ore.


Figure 8 Browns Tunnel Pit

The pit will cover a surface area of 19,109 M2.

Haulage of Ore

Haulage of ore from the site will be undertaking by contract haulage operators within road registered semi-tipper or truck and dog combinations at a rate of 25 tonnes per load. The haulage route will be via the Southern Trenches Road, the Boco Forestry Road and the Murchison Highway to Rosebery.

495

480

465

450

435

420

BURNS TUNNEL PITTOTAL 613,156m3


MANAGEMENT OF POTENTIAL ENVIRONMENTAL IMPACTS

Assessment of Environmental Impacts

Environmental issues were assessed by reviewing the proposed operation against a checklist developed from Leopold’s original matrix (Table 4). A risk assessment was then carried out against each of the expected impacts from the operation to rate the priorities for investigation and management (Table 5). It is envisaged that the risk assessment will be completed in the final DPEMP by adding an assessment column for mitigated risks based on management protocols devised by the various studies recommended by this risk assessment.

Table 3 EIS matrix assessment

Assessment of Impact on Receiving Environment

Burns Peak Operation Stages 1 & 2 YES NO Comment

Is site part of conservation estate/agreement/treaty?

national park X

conservation park X

resources reserve X Burns Peak Forest Reserve - does not exclude mining

nature refuge X

co-ordinated conservation area X

wilderness area X

world heritage management area X

international agreement area X

Is it an environmentally significant area?

Geomorphological characteristics: X

wetlands X

lakes X

coastlines and dunes X

islands X

rivers or estuaries X Strong Creek ruins into Marionoak River

arid zones X

karst

Ecological systems:

flora and fauna (uncommon/threatened/endangered) X

mangroves X

environmentally sensitive marine localities X

saltmarshes X

coral and seagrass meadows X

rainforest X

old growth indigenous forests X Previously harvested & disturbed

desert communities X

urban bushland X

remnant vegetation X

wildlife corridor X

Vulnerability to major natural or induced hazards?

flood prone areas X

steep slopes X West facing ridge from Burns Peak

catchment for ground and surface water resources X Surface flows to Marionoak River

bushfire prone area X

Is site a special purpose area?

aesthetic or high scenic value X

land use designation (TP scheme zone) X

recognised tourist area X

area targeted for growth X

other special purpose (defence/communication/etc) X Mining province since 1899


Are human communities vulnerable?

previous pollution/contamination X ARD & water qlty issues from mining

socio-economic factors X

assimilation potential X

Does proposal involve a renewable/non-renewable resource?

oil/gas/coal/gravel/sand/mineral X

forest area X Forest reserve may require offsets

fish breeding area and fishing ground X

good agricultural land X

Is site degraded or a potentially contaminated site?

air quality/pollution X

surface water quality/pollution X ARD & water qlty issues from mining

groundwater quality/pollution X

soil quality/contamination X Mining province since 1899

geological stability X

POTENTIAL PROJECT IMPACTS

Will significant change occur in the receiving environment?

Physical Factors X Underground operation. Minimal surface disturbance. Small open cut

significant land disturbance X

erosion, subsidence and instability X

alteration of water courses/drainage patterns X

effects on quantity/quality/availability of surface or groundwater X Potential to mitigate ARD from previous operations

alteration of wetlands/mangroves/lakes/estuaries X

earthworks in water inundated areas for creation of islands/basins etc X

likelihood of salinisation X

effects on coastal processes (wave action/sediment movement or X accretion/water circulation patterns)

Biological Factors

threat to biodiversity X

threat to maintenance of ecological processes X

involves extensive clearing/burning/modification of vegetation X

threatens ecological processes or life support systems X

displaces fauna or creates significant faunal movement barriers X

may introduce noxious weeds/vermin/feral species/disease etc X Weed management necessary

risk of fire X Fire management necessary

use of environmentally persistent pesticides/herbicides/fertilisers X

Land Use

major changes of land use X

significant difference to surrounding land uses or strategic zoning X

involves the reservation/alteration or alienation of Crown land X

involves significant change to economic value of land/water X

curtails alternative beneficial uses of area X

places increased demands on natural resources in local short supply X

Resource Use

development of alternative uses of a natural resource is foregone X

may significantly affect the livelihood of existing users X

may disrupt other industries using a locally renewable resource X

Community

involves large population movement X

may cause significant change to local/regional demographic structure X

may cause significant change to local/regional economic structure X

may cause disruption to quality of life through downstream pollution X

community concern through vulnerability/privacy/safety/amenity etc X

Infrastructure

significant increase in demand on:

local services/infrastructure (roads, power, water, waste, housing etc) X

Heritage

any adverse effects on Aboriginal communities X

may cause damage or increase exposure to Aboriginal sites etc X


may adversely affect other sites or items of historic significance X

Aesthetics

obstruction of views X

exceeds local planning authority restrictions X Planning permit needed

degrades scenic amenity by extensive clearing/land disturbance X

major illumination or reflection impacts on adjacent properties X

may cause creation of adverse wind effects X

Could project give rise to unhealthy/unsafe conditions?

Air

cause significant generation of dust/smoke/odours/toxic gases etc X

greenhouse gas contributions (CO2,CH4,NO,O3,CFCs,water vapour) X Short term small scale mining project

Water

significant deterioration to local water quality (salinity/colour/odour/ X Potential for ARD issues and impact on ground and surface waters

turbidity/temp./DO/nutrients/pH/heavy metals/oil/toxins etc)

possible accidental spills into aquatic environment X Chemical and hydrocarbon management necessary

Wastes

disposal of significant volumes of sewage/industrial waste X

disposal of significant volumes of spoil/overburden/process wastes X Underground operation and open cut small volumes

Hazards

hazards due to use/storage/disposal/transportation of substances X Chemical and hydrocarbon management necessary

emission of electromagnetic or other significant radiation X

Noise Factors

significant increases in road/rail/aircraft/marine noise and/or vibration X Additional road transport of supplies and ore significant increase in plant machinery/site activities noise and vibration X Consider the potential for cumulative environmental impacts on the region X

Will the project significantly divert resources (at cost to others?)

provision of services and infrastructure X

opportunity costs/options foregone X

ongoing industrial viability and competitiveness X

RESILIENCE OF ENVIRONMENT TO COPE WITH CHANGE

Can the receiving environment absorb and/or recover? X Opportunity to provide long term improvements to water emissions

consider assimilative capacity X Opportunity to improve previous closure planning

consider potential for rehabilitation X Closure and rehabilitation planning necessary

Can adjacent land uses be sustained?

consider viability and competitiveness of existing neighbours X

Can sustainable uses of site be achieved beyond project life?

consider future uses X Closure and rehabilitation planning necessary

Risk Assessment

The overall methodology for the Risk Assessment has adopted the recommended approach as outlined by the Australian and New Zealand Standard, Risk Management, AS/NZ 4360.

Identifying the Hazards

This initial step seeks to identify potential hazards and the modes by which they may occur. It is conducted using a structured, systematic process to ensure that all possible hazards are identified. Thus, the hazard identification process included:

discussions with mining, & environmental personnel,

desktop review of available information,

and site inspections.

In all cases, the process considered the potential timescale and extent of influence of the hazard’s effect.


Risk Ranking

Methodology

The objective of the assessment is to evaluate the risks associated with potential operational aspects on a semi quantitative basis to provide a mechanism for prioritizing hazards. The risk is scored using a semi quantitative numerical scoring system that combines estimates of the likelihood and consequences of a hazard in the context of the existing control measures. The risk analysis provides a ranking system with the capacity to be used compare and prioritize risks associated with each hazard.

The evaluation of likelihood and consequence involves comparing the significance of the hazard against predetermined criteria. The following table outlines the general assumptions used to categorize the likelihood and consequence of the identified hazard:

Likelihood of Occurrence.

Numerical Ranking Description 1 Rare Hazard is unlikely to occur within lifetime of project operations. Low

likelihood of occurrence. No further management controls are required to minimise potential for occurrence.

2 Low Minor management control may need to be considered to reduce likelihood of occurrence.

3 Moderate Hazard has moderate likelihood of occurrence. Appropriate management control can result in low likelihood of occurrence.

4 High Appropriate management control may not be sufficient to minimise likelihood and thus engineering or design solutions may need to be considered.

5 Almost Certain Hazard will inevitably occur or has already occurred. Management controls cannot practically minimise likelihood of occurrence to acceptable levels. Engineering or design solutions are required.

Consequence of hazard

Numerical Ranking Description 1 Low Negligible or acceptable impact. No further management controls are

required assuming no change to current conditions. 2 Low to Moderate Impact may be acceptable. Further monitoring is required to establish

potential significance. Implementation of simple management controls may be required.

3 Moderate Moderate impact. Potentially acceptable if appropriate management controls are implemented.

4 Moderate to High Impact has the potential to be unacceptable. Further monitoring may be required to establish potential significance. Implementation of appropriate management controls is required.

5 High Unacceptable impact. The potential impact has a high severity and cannot be managed should it occur.


Risk Ranking Matrix

The ranking for likelihood and severity are combined in a matrix to establish an overall risk ranking as follows:

Consequence

Likelihood Low

(1)

Low to Moderate

(2)

Moderate

(3)

Moderate to High (4)

High

(5)

Rare (1)

1

Low

2

Low

3

Low

4

Moderate

5

Moderate

Low likelihood (2)

2

Low

4

Low

6

Moderate

8

Moderate

10

Moderate

Moderate Likelihood (3)

3

Low

6

Moderate

9

Moderate

12

Moderate

15

High

High Likelihood (4)

4

Moderate

8

Moderate

12

Moderate

16

High

20

High

Almost certain (5)

5

Moderate

10

Moderate

15

High

20

High

25

High

Where - High Degree of Risk - Score above 15 inclusive, Moderate Degree of Risk - Score between 5 – 15, Low Degree of Risk - Score between 0 – 5 inclusive.

Hazards which are considered to have a low risk would be periodically monitored to assess whether the status of the hazard has altered. For example, based on the sample risk matrix, a low degree of risk (score 0 - 5) would indicate that the potential hazard/impact was acceptable and that no additional management controls are required. Conversely, when neither the consequence nor frequency, of the hazard/impact can be appropriately managed, the risk would be regarded as high (score above 15) and should be engineered to reduce or remove the hazard. In comparison, hazards with a moderate risk may need only to be mitigated through administrative changes (procedures etc).

Hazard Risk Evaluation

This section of the study has been presented in spreadsheet form for ease of reference. The table summarises the outcome of the environmental hazard identification and risk evaluation study as outlined. It must be understood that the values of likelihood and consequences, which have been assigned in this table, are based on subjective interpretation and experience. The risk rankings are intended to provide a basis for prioritizing the hazards as outlined and should not be interpreted as a relative magnitude of risk. There may be orders of magnitude difference in risk between each hazard. In addition, the consequence of the hazard is based on the most sensitive environmental receptors. Hence, in some cases, the environmental receptor may be people, whilst in others this may be ecological species, aesthetic issues or amenity.


Table 4 Preliminary Risk Assessment Burns Peak

Surface Footprint

The proposed mining lease covers an area of approximately 143 hectares, embracing the former open cut mine, costean trenches and sufficient area for water treatment, ore

Burns Peak Operation - Preliminary Risk Assessment

ITEMENVIRONMENTAL ASPECT

Source Consequence Rating Likelihood RatingRisk

RankingSummary of Action Required

Atmospheric emissions1 Gaseous by products of

combustionDiesel exhausts from mining f leet and light vehicles

Soot, diesel particulates, hydrocarbon emissions, VOC, SOx, Nox, CO, CO2

2 Low . Minor combustion engine emissions

1 2 Cost eff icient f leet selection and management. Ventilation of underground operations

2 Greenhouse gases2.1 Greenhouse gas mainly

carbon dioxideCombustion by products from internal combustion engines. Mining fleet & light vehicles

Addition to global w arming. Tasmania is a greenhouse positive state w ith hydro pow er


1 2 Desktop calculations of greenhouse gas emissions.

2.1 Greenhouse gas mainly carbon dioxide

Transportation of goods and products

Addition to global w arming. Tasmania is a greenhouse positive state w ith hydro pow er


1 2 Desktop calculations of greenhouse gas emissions.

3 Dust generation3.1 Dust from product

movementsRaw material transfer Dust settlement on site.

Considerable distance to off-site human receptors.

2 High rainfall at site means that dust levels w ill be low .

1 2 Routine informal site dust monitoring.

3.2 By products of combustion Diesel exhausts from mining f leet and light vehicles

Soot, diesel particulates. Considerable distance to off-site human receptors.


1 2 Cost eff icient f leet selection and management. Ventilation of underground operations

3.3 Dust generated from road use

Source of fugitive site dust.

Dust settlement on site. Considerable distance to off-site human receptors.

2 Site rainfall means that dust levels are low .

2 4 Road w atering

4 Noise4.1 Mining f leet noise Noise associated w ith

running a small mining fleetDisturbance to people in noise sensitive areas.

2 Nearest sensitive receptor >6k distant. Daylight hours w orking only

1 2 Desktop calculations of noise levels in DPEMP

5 Acid Rock Drainage5.1 ARD from UG w orkings

reporting to ground and surface w aters during dew atering

Underground w ater from dew atering old mining w orkings

Impact on river system w ater quality and on dow nstream species abundance and diversity.

5 High dissolved metal loads w ill need treatment and resulting hydroxide sludges w ill need secure storage

3 15 Develop pumping system to take acidic w ater to holding dam for treatment prior to release

5.2 Ongoing ARD from legacy w aste rock dump, pit and costeans

Sulphides exposed to air w ith oxidise

Impact on river system w ater quality and on dow nstream species abundance and diversity.

5 Acidity and high dissolved metal loads w ill need treatment and resulting hydroxide sludges w ill need secure storage.

5 25 Hydrogeological and geochemical investigation needed to evaluate magnitude of problem and develop treatment and storage solutions. Effective closure plan to stop oxidation also required

5.3 ARD from exposed pyrites in new UG and open cut mining operations

Sulphidic material w ill be exposed during mining

ARD contamination of surface w aters from mine dew atering

5 Acidity and high dissolved metal loads w ill need treatment and resulting hydroxide sludges w ill need secure storage.

4 20 Hydrogeological and geochemical investigation needed to evaluate magnitude of problem and develop treatment and storage solutions

6 Water emissions6.1 Treatment dam decant Treatment dam fails to meet

specified emission limitsImpact on river system w ater quality and on dow nstream species abundance and diversity.

4 Cause of deteriorating w ater quality needs to be quantitatively determined

4 16 Review technology and set up management control loop

6.2 Stormw ater runoff from disturbed areas

Sediment loads & metals in solution from contaminated areas of mine site

Impact on river quality if settling is insuff icient or metals remobilise

4 TSF and or w etlands could be used to settle out TSS and turbidity.

2 8 Effective w ater management plan needed

6.3 Treatment Dam failure Loss of metal hydroxides into Strong Creek

Pyrite & heavy metal & sludge discharges into receiving w aters

3 End of costean to be backfilled and clay costean to form a a seal. Less than ANCOLD size limits

3 9 Review construction & loadings on proposed dam and have engineer review

7 Fire7.1 Bush Fire Site operations ignite forest

bushfire, eg. tip f ires, use of hot equipment etc.

Damage to rainforest areas. Combustion and exposure to intense heat.

4 No reported incident w here fire has been identif ied as being started directly by previous operations.

2 8 Ensure adequate buffer to nearby vegetation from active areas. Formal f ire management protocol required.

8 Chemical storage & handling8.1 Chemicals Fire Fire in areas of

hydrocarbon storage or refuelling areas.

Waste f ire w ater enters river system via stormw ater drainage. Impact w ill be short term.

3 Fire management plan w ill be in operation on site.

2 6 Formal f ire management protocol required. Protocol for containment and treatment of w aste w ater required. Specialist f ire fighting equipment installed in key locations.

8.2 Diesel storage tank or bund failure

All hydrocarbon storages to AS 1940 -1993.

Spill causes localised soil contamination.

3 Low . Minor storage quantities

2 6 Conduct regular area inspections


stockpile, waste dump, topsoil stockpile, office, haul roads, and drainage diversion structures.

Figure 9 Aerial photo showing current areas of impact

However with the small scale of the operations the development of Stages 1 & 2 will only necessitate the removal of approximately 5 ha of native vegetation. Stage 3 will see a further 2 ha of vegetation removed for the pit with another 2 -3 ha removed for roads and ancillary infrastructure associated with the pit. To avoid impacts where possible and to reduce impact where unavoidable Mancala will commit to: Utilizing where possible, existing disturbed areas to site proposed infrastructure

Clearly defining the extent of clearance required for the project, defining the timing of each stage. Minimise the extent of vegetation clearing, and ensure that any additional impacts are considered. In designing and developing access roads and tracks, Mancala will alter routes to avoid identified potential denning habitat as much as possible.

Investigate implication of land tenure within the Burns Peak Forest Reserve. Consult the District Forester of Forestry Tasmania and provide like for like offset for any losses of reserved land.

Prepare a devil and spotted-tailed quoll management plan. The plan will cover buffer zone surveys of suitable denning habitat, mine site interactions with animals and habitat, and appropriate mitigation measures.

Reduce the risk of introduction and spread of plant pathogens, and declared and environmental weeds, during and after works, by implementing vehicle hygiene, weed management, and spread prevention plans.

Prepare plans that prescribe limits to access and works on site to the defined footprint of the project.


Waste Rock

During Stage 1 activities the waste rock will be temporarily stockpiled on the low relief area west of the pit workings. Based on drill core NAG and NAPP sampling and the presence of the same lithology’s at depth (20m) in the resource drilling all waste rock below 13 metres depth is expected to be PAF consisting of highly weathered and oxidised volcaniclastics. This material (approximately 20,00 BCM) will be stockpiled for a period of approximately 11 months, being the duration of Stage 1 and 2 activities. Kinetic acid base accounting is being undertaken to evaluate the potential impact and mitigation of impacts from this. Sufficient alkalinity will be added to the waste rock during deposition (along with paddock dumping in 5 metre layers to exclude oxygen ingress) to extend its pre oxidisation lag phase so that no sulphide oxidation occurs during the 11 - 33 months of stockpiling. The Stage 1 waste rock will be the placed back into the pit during closure and rehabilitation and capped with a compacted clay cover to exclude oxygen ingress and prevent sulphide oxidation. NAG and NAPP determinations of the host rocks surrounding the ST Deeps mineralisation indicate the majority of lithology’s are NAF in character. Some low grade PAF rocks are present associated with disseminated pyrite within volcaniclastics sequences. The geochemical nature of lithology’s to be traversed by the decline will be investigated by a dedicated cover hole. Intuitively it is anticipated these rocks will also be largely NAF in character. The total volume of rock to be excavated by Stage 2 development activity is approximately 5,800m3. Rock which is determined either by the cover hole or by the site geologist to be PAF will be stored within the ST Pit access roadway. NAF material may be used around the site for infrastructure work. If all rock excavated was determined to be PAF there is ample storage capacity (8,000m3 to 390.5 RL) within ST Pit to ensure that all PAF waste is stored sub aqueously. Old drill core from the Browns Tunnel area has been reviewed by Mancala to assess both the ore resource and the waste rock. Lithology for this proposed pit is the same as in the Costean pit for the purposes of waste rock assessment and management, similar prescriptions for waste rock geochemistry have been assumed, i.e. NAF waste associated with the dacites and clays to a depth of 15 metres with all waste below that classified as PAF. This produces 215,993 M3 of NAF waste and 378,285 M3 of PAF waste. PAF waste from Browns Tunnel will be hauled to the legacy waste rock dump (see Figure 9) where it will be layered and compacted in 5m lifts to prevent the ingress of oxygen and minimise sulphide oxidation. The waste rock dump will cover a surface area of 39,772 M2 extending north and west from the existing waste dump. Additional resource drilling to be carried out during Stage 1 and 2 operations will further define the geochemical characteristics of the Browns Tunnel pit. This may see the amount of waste and amount of PAF reduce from the worst case scenario outlined in this document.

Mine Water

The small open cut being developed in Stage 1 will be self-draining, with both ground water and incident rainfall reporting to a settling pond located adjacent to the pits access ramp. Overland flow will be prevented from entering the pit by constructing diversion drains.


Water management around and in the pit will be facilitated by: Diversion drains around the eastern high wall; Free draining nature of pit; A sediment trap constructed at the entrance to the ramp; and Sediment traps at the toe of both the soil and waste rock dumps.

At the completion of Stage 1 mining a compacted impermeable wall will be constructed in the pit access with the intention of impounding water to form a settling area for the water treatment activities of Stage 2.

Figure 10 Schematic representation of water management during Stage 1, Costean Lode

The underground development of Stage 2 will encounter ground water which will have to be pumped from the workings and treated (at a minimum for sediment settling) prior to release to the environment. In addition water in the Southern Trenches pit will require removal and treatment as the stoping operations will extend upward to the pits floor. This water has become acidified and polluted with metals in solution due to the oxidation of sulphides in the pit wall. It will need treatment to remove these metals prior to release into the environment. It is planned to use the Stage 1 pit as a settling dam for contaminated water produced in Stages 2 and 3. Use of the pit is preferred as the alternative of constructing a dedicated dam would cause significant disturbance (owing to the areas high relief), would be expensive and would create a long life, high maintenance liability post mine closure. Stage 3 water management will follow the same basic criteria as for Stages 1 & 2, i.e. upstream diversion drains to divert clean water away from the workings, and downstream sump to settle solids (see Figure 12). Where pit water is clean (pH>6.5 and EC < 500 µs/cm) it will be allowed to decant from the settling pit to the nearest water course. Where water from the settling pit does not meet these criteria it will be pumped to the Costean Pit for treatment and setline prior to discharge.

Pit

Soil Stockpile

Waste Rock Dump

Tributary to Marionoak River

Settling Pond

Settling Pond

Diversion Drain


Figure 11 Schematic Representation of Water Management during Stage 2 mining

Figure 12 Layout Browns Tunnel

ST Pit

Costean Pit

U/G Workings Decline Face

De-Watering

Settling Pond

Strong’s Creek

Tributary of Marionoak River

De-Water Bore Hole

Water Treatment

DiversionDrain3mw x 1md 45⁰ Will catch and divert all clean water from entering the pit

PIT ACCESS RAMPMain access ramp to the pit @ 471mRL

Existing RoadsCreekFresh water run off is diverted into this creek

TOTAL SURFACE AREA15m Bench Interval70⁰ Batter19,109m2


Traffic

The mining at Burns Peak will operate 5 days per week during daylight hours. This will limit any impact from haulage of ore to Rosebery. As the agreement with the MMG Rosebery concentrator is for a weekly production limited to 1,000 tonnes per week, this equates to an average of eight loads per day on the Murchison Highway.

Figure 13 Site Haulage Route

Rehabilitation and Closure

Rehabilitation of the Costean Lode Pit will involve reforming the landscape to mimic a natural setting and in so doing so rehabilitate the deep existing costean. On completion of mining a free draining pit will be present along with adjacent soil and waste rock stockpiles. The rehabilitation concept involves: The construction of an impermeable barrier in the access ramp to prevent sub-

surface flow and saturate any remaining sulphides within the pit; Sequential replacement of stockpiled materials back into the void; Drainage re-establishment; and Re-vegetation.

The high clay component of the waste rock is likely to permit some of the excavated material to be used in the impermeable barrier. Its use will be subject to geotechnical appraisal. If unsuitable, a small (2,000m3) clay borrow pit location has been identified adjacent to Thomas’s tunnel.


Besides the rehabilitation of tracks and laydown areas by ripping and soils spreading, the major rehabilitation activities involve the Stage 2 underground workings and the ST Pit. Mancala plan to ensure the workings are flooded to prevent acid rock drainage formation. To facilitate this, a pressure resistant concrete plug will be installed near the decline entrance. The Stage 3 pit will be cut into the slope of the hill to the northeast (See Figure 8). This means that the remnants of the sulphide orebody which slopes downward and to the north will be flooded on closure of the pit. There may also be scope for deposited waste materials into the pit and covering these with compacted clays prior to closure.

Legacy Environmental Disturbance and ARD

The Burns Peak Operation provides an opportunity to address existing environmental disturbance and sources of Acid Rock Drainage (ARD) as part of the operations environmental management plan. The major legacy environmental issues on the site consist of:

A number of deep costeans traversing the flanks of Burns Peak which remain un-rehabilitated and un-vegetated;

ARD resulting from exposed sulphides in costeans and disturbed areas; Un-rehabilitated tracks and clearings associated with past exploration activity; ARD emanating from turn of the century underground workings; ARD generated within and flowing from the Southern Trenches pit; Lack of significant re-vegetation surrounding the Southern Trenches pit; and ARD seeping from the toe of the Southern Trenches Pit waste dump.

The staged approach to development at Burns Peak will allow the legacy issues to be addressed in line with the stages and scale of operations on the site.

Table 5 Proposed activity stages and Remediation Works

Stage Stage Activity Legacy Amelioration Activity Pre-Work

Environmental base line surveys

Assessment of the location and scale of past environmental disturbance, on particular ARD sources.

1 Small open cut on Costean Lode

Removal and/or aqueous isolation of ARD producing sulphides. Rehabilitation of some 200m of deeply incised costean and roadway

2 U/G mining of Southern Trenches Deeps mineralisation

Treatment of ARD accumulation in Southern Trenches Pit and construction of impoundment wall in pit to raise water level above exposed sulphides. Re-vegetation of pit and rehabilitation of roadways and costeans.

3 Conceptual Mining of Browns Tunnel resource by open cut methods

Removal of Browns Tunnel ARD source, encapsulation of existing waste dump ARD seep, rehabilitation of access tracks and disturbed areas.

Consultation

Ongoing public and key stakeholder consultation is planned as the project develops and specific information on the mining and trucking proposed is available. Initial discussions have been held with the Tasmanian Aboriginal Land and Sea Council (TALSC) and a formal survey is planned.


Mancala has also commenced negotiations and information secessions with the projects major stakeholders. These consist of:

o MMG via heads of agreement. EL owner; o MMG via ore sales agreement; o Tarkine Trails – eco lodge and bush walking tourism operator; o Tarkine Collation – environmental activist group seeking high level reserve

status for the area between the Pieman an Arthur Rivers; o Forestry Tasmania – underlying land manager and manager of Boco access

road; o Bee Keepers – access road interaction discussions; and o Waratah Wynyard Council – local planning and approval authority.

Key Environmental Issues Mancala believes that the key environmental issues for the Burns Peak Operation will be:

Water quality. Management of water exposed to sulphidic material being discharged from the decline and management of existing acidic water on site.

Acid Rock Drainage (ARD). Management of acid rock drainage.

Development of closure and rehabilitation plans which return the site to a stable durable landform (commensurate with its condition before this proposed operation) with no long term, unacceptable adverse impacts (primary or secondary) as a result of this proposed operation.

Miscellaneous Environmental Issues

Minor issues which will need to be addressed in the Development Proposal and Environmental Management Plans for the Burns Peak Operation will include:

Transport of goods to and from the mine

Emergency and Fire Management

Noise Management

Air quality management

Solid Waste management.

These are not expected to present significant difficulties and will be managed through effective planning and management practices.


REFERENCES Bureau of Meteorology Website, Burnie Round Hill Meteorological Station DIER Website (Transport), Connecting Tasmania – Draft Tasmanian Road Hierarchy and Targets. DPIWE 1997. State Policy on Water Quality Management, Tasmania. Forest Practices Authority (2011). Wedge Tailed Eagle Nest Search. Burns Peak Region. Report for Mancala Pty Ltd. North Barker Ecosystem Services (2012) Burns Peak Mine Proposal. Botanical Survey and Fauna Habitat Assessment.


Appendix 1 EPBC Referral

Documents

MANCALA RESOURCES PTY LTD NOTICE OF INTENT Burns Peak ...epa.tas.gov.au/documents/mancala resources pty ltd... · mining is the trenches or mini open cuts plus adits or tunnels. The