Development Proposal and Environmental Management Plan … Coal Mining... · 2012-08-31 ·...

Hardrock Coal Mining Pty Ltd – Fingal Tier Coal Project DPEMP Supplement

FINGAL TIER COAL PROJECT

Development Proposal and Environmental Management Plan

Supplement

Prepared for: Hardrock Coal Mining Pty Ltd

July 2012


CBM Sustainability Group 2

CLIENT: Hardrock Coal Mining

PROJECT: Fingal Tier Coal Project Development Application

JOB NO: 25159P

This Report has been prepared in reliance on data, surveys, analysis, designs, plans and other information provided by the client, and other individuals and organisations referenced herein. Except as otherwise stated in this report, CBM has not verified the accuracy or completeness of such data, surveys, analysis, designs, plans and other information. The passage of time, manifestation of latent conditions or impacts of future events may result in the actual contents differing from that described in this report.

No responsibility is accepted for use of any part of this report in any other context or for any other purpose by third parties.

This report does not purport to provide legal advice. Readers should engage professional legal advisers for this purpose.

CBM Sustainability Group Pty Ltd

8 Broadland Dve, PO Box 1971

Launceston Tasmania 7250 Australia

Telephone: (03) 63326999

Facsimile: (03) 63318300

Email: [email protected]

Date Purpose of Issue/Nature of Revision Revision No. Authorised by

15/04/2012

19/06/2012

23/07/2012

30/07/2012

Draft Submission to EPA



Final Issue

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02

03

04

SD

SD

SD

SD



Contents

1 Introduction .......................................................................................................................... 4

2 Public Representations .......................................................................................................... 5

2.1 Summary ....................................................................................................................... 5

2.2 Comments and responses ............................................................................................. 5

2.2.1 Flora and Fauna Assessments ............................................................................... 5

2.2.2 Land stability ......................................................................................................... 6

2.2.3 Groundwater ......................................................................................................... 6

2.2.4 Compatibility with planning Codes ....................................................................... 7

2.2.5 Traffic Safety.......................................................................................................... 8

3 Referral Agency Comments ................................................................................................... 9

3.1 DPIPWE Heritage Tasmania ........................................................................................... 9

3.2 DPIPWE Resource Management and Conservation ...................................................... 9

3.3 EPA division ................................................................................................................. 11

3.4 DIER - Mineral Resources Tasmania (MRT) ................................................................. 18

3.5 Forestry Tasmania ....................................................................................................... 24

3.6 DIER Roads and Traffic Division ................................................................................... 26

3.7 Supplement Revision 2 comments .............................................................................. 28

4 Revised Commitments ........................................................................................................ 43

5 Appendices .......................................................................................................................... 45



1 Introduction

A DPEMP for The Fingal Tier Coal Project was advertised for public comment on 21 January

2012. The Break O’Day Council received two public representations, and the EPA received

comments from a number of State Government departments. These representations and

comments were reviewed by the EPA and made available to Hardrock Coal Mining (HRCM) in

the form of a supplement request. This document seeks to provide the information requested

through this process.



2 Public Representations

2.1 Summary

Two representations were received from the public during the advertising period. The first was

received from Peter and Beverley Rubenach in regards to concerns around traffic safety and

coal and noise emissions from the coal stockpile area. Peter was met on site by CBM staff on

22nd February 2012, and the plans for the proposed coal stockpile and rail loading facility were

outlined. It was explained that this project would be the subject of a separate Development

Approval process. This alleviated Peter’s concerns, and a letter was received by Break O’Day

Council on 28th February 2012 advising that the representation to the project was withdrawn.

The second representation was received from the North East Bioregional Network. The

President, Todd Dudley was met onsite on the 29th March 2012 to outline the development

and show the impacts of previous mining and forestry activity on the site. A formal meeting at

the Break O’Day Council offices was held 16th of April 2012, in which the representation

comments were discussed in detail.

2.2 Comments and responses

2.2.1 Flora and Fauna Assessments

Comment – Representation 1 critical of the deficient design of the Botanical Survey and Fauna

Assessment, particularly with respect to Fauna Assessment.

Response - A follow-up botanical survey has been undertaken by GHD, including a site

assessment on the 7th March 2012. This survey did not identify any threatened flora species,

and when combined with the original botanical survey undertaken in late winter 2011,

provides for a comprehensive understanding of the flora and vegetation communities on the

development site. This report is attached in appendix 1.

The survey methodology used for the fauna habitat assessment was provided to DPIPWE’s

Policy and Conservation Assessment Branch (PCAB), and in conjunction with the Wedge-Tailed

Eagles impact mitigation work completed, PCAB advised CBM that a further targeted survey

would not be required. This advice is included as Appendix 4.



2.2.2 Land stability

Representation 1 noted that Strata report (Appendix 10) indicated potential for instability in

the area proposed for mining.

Response – The desktop review of land stability is only relevant to the construction of

aboveground infrastructure items on the project site. The detailed mine planning includes

underground geotechnical testing and analyses in order for the engineering design of the mine

to occur.

2.2.3 Groundwater

Comment – Representation 1 indicated that HRCM had not clearly identified and discussed

possible impacts to groundwater.

The potential impacts of the proposed development on the surrounding groundwater are

clearly identified in section 5.1 of the Hydrogeological Survey. The Stage 2 Hydrogeological

Review (attached as Appendix 7), has now been completed, following the collection of further

hydrogeological information, including:

Observations of core recovery, to identify areas of core loss indicative of fractured zones or poorly consolidated sandstone horizons with potential to act as high permeability zones;

Observations of drilling fluid returns to identify areas of high permeability associated with fluid loss;

The monitoring of water levels during drilling to gain an indication of the piezometric heads a various depths;

Packer testing of targeted horizons to obtain quantitative hydraulic conductivity data;

Installation of grouted-in vibrating wire piezometers, to provide head data in individual strata in exploration hole; and

Collection of water samples from re-opened adits and adjacent background creeks to gain an early indication of likely mine water chemistry.

This has allowed the development of a numerical groundwater flow model for the area to be

mined in the first 3 years of operations, and an assessment of the quality of the groundwater,

which has informed the development of a mine water balance and the conceptual design of



the onsite water infrastructure. The Stage 2 Hydrogeological Review has also allowed for the

further analysis of potential groundwater impacts attributable to the mining activity. These

impacts are discussed in section 8 of the Review and can be summarised as:

Depression of water tables and aquifer depressurisation. Mine dewatering can lower groundwater levels, impacting on other groundwater users, groundwater dependant ecosystems and surface water base flows. Given the evidence for isolation of the F seam and coal measures in general from overlying shallow dolerite aquifers, the overall low permeability of the coal measures and the likely low inflow rates, it is unlikely that dewatering operations will significantly alter water levels in sensitive areas on the Fingal Tier, or impact on base flows in Cardiff Creek;

Acid and Metalliferous Drainage. Lowering of groundwater levels can expose sulfidic rock to oxidisation and generation of acid or metalliferous drainage. As discussed above, the coal measures are relatively impermeable and hence any depressurisation/dewatering associated with mining is likely to be localised. Furthermore, AMD testing to date shows the risk of AMD generation is low due to the low sulfide sulfur levels, high neutralising capacity of the coal measures and generally low metal content;

Mine water discharge. Discharge of excess water from mine dewatering can impact on downstream water quality. However, based on the geochemistry of the coal measures, observed adit water chemistry and anecdotal evidence from the Duncan colliery, water quality from the mine is expected to be suitable for re-use on site and for off-site irrigation or discharge to surface water bodies if there is an excess. Modelling of the Stage 1 development, using both a calibrated model and a stochastic distribution model indicated similar steady-state inflows with a 90th percentile inflow rate of 1.5 L/s.

Contamination from mining equipment and site infrastructure. As with any activity involving the use of heavy machinery, there is the potential for contamination from hydrocarbons leaking from the equipment or from on-site fuel storage. The risk of contamination of the coal measures is low due to their low permeability and the fact that the groundwater flow direction will be inward to the mine. The main risk will be to shallow unconfined aquifers such as local alluvial aquifers or the surficial fractured dolerite aquifer.

Further hydrogeological investigations will be undertaken in conjunction with ongoing

resource definition and operational drilling, to develop the groundwater flow model beyond

the first 3 years of operations.

2.2.4 Compatibility with planning Codes

Comment – Representation 1 suggests that the location of the proposed activity conflicts with

the intent of sections of both the Biodiversity and Wetlands and Waterways Codes respectively.



Response - Reference to the Biodiversity Code is not relevant as this is contained in the Break

O’Day Draft Interim Planning Scheme.

The statement that the proposal is in conflict with the Wetlands and Waterways Code of the

Break O’Day Planning Scheme 1996 is not substantiated, but is rather an opinion offered by

the petitioner.

The proposal has demonstrated compliance with the Wetlands and Waterways Code, primarily

through the commitments 5 and 7, and section 4.3.4 of the DPEMP. Further, a statement has

been received by the consultant undertaking the design of the proposed site water

infrastructure, and is attached in appendix 3. This confirms that the design of any works or

structures within 30 metres of the outer boundary of a wetland or waterway will be in

accordance with Best Practice Environmental Management, and in particular with Sections 2-7

of the Wetlands and Waterways Works Manual (DPIWE and LGAT, 2003).

2.2.5 Traffic Safety

Comment – Representation 2 queried the forecast traffic frequency/volume on Valley Road and

highlighted that there had been two fatalities on or near the Esk Hwy/Valley Rd intersection in

recent years (events not mentioned in the Traffic Impact Assessment). Fog and frost were also

raised as conditions likely to affect road safety.

Response - This comment assumes that coal haulage trucks would be using the Valley Rd/Esk

Hwy intersection to transport coal to the rail loading facility. This is not the case, and upon

outlining the draft plans for the Esk Hwy underpass and new rail loading facility to the

petitioner, which will be assessed in a subsequent Development Approval, the entire

representation was withdrawn.

Only one fatality was listed on DIER’s crash statistics database, and this occurred

approximately 1 km east of the Valley Rd/Esk Hwy intersection and thus was not deemed

relevant to the Traffic Impact Assessment.



3 Referral Agency Comments

3.1 DPIPWE Heritage Tasmania

Comment – Commitment to produce a Heritage Management Plan is commended, and should

be undertaken by an archaeologist familiar with the Tasmanian Heritage Council’s Practice

Note 2. It should include a discussion about unanticipated discoveries, and follow methodology

outlined in the Heritage Tasmania’s Predevelopment Assessment Guidelines.

Response – HRCM will ensure that a Heritage Management Plan is prepared for construction,

and will include the information requested above.

3.2 DPIPWE Resource Management and Conservation

Comment – PCAB considers the Botanical Survey and Fauna Habitat Assessment to be deficient

due to design limitations (single event during winter comprising two days only). HRCM must

justify/clarify why it considers the assessment to be a representative effort.

Response - As outlined in section 2.2.1, a follow up botanical survey has been completed and

now provides for a comprehensive understanding of the flora and vegetation communities on

the development site.

Comment – The assessment highlights the potential for several fauna species to be present in

the area likely to be disturbed by mining activities but does not provide enough detail relating

to actual survey methodologies adopted and area of land covered/sampled. Specific

information should be provided that addresses actual impacts to fauna and whether mitigation

options are relevant/applicable for each specifies affected.

Response - The survey methodology used for the fauna habitat assessment was detailed to

PCAB, and PCAB determined that the adopted methodologies were adequate for the purpose

of the DPEMP. CBM was advised that no further surveys would be required on site (refer

appendix 4). Further, HRCM has committed to the preparation of a Special Values

Management Plan, which will further develop management strategies for known and likely

fauna in and around the development site.



Comment – Furthermore, in the event that any major infrastructure such as water

improvement ponds and/or catchment dam needs to be re-sited for geotechnical reasons, then

additional survey work to determine the natural values of and recommend management

measures for the area of relocation is likely to be required. Again, this work will need to be

conducted and reviewed prior to issue of any final approvals of the proposed activity.

Response - As stated in section 2.1.2, the aboveground infrastructure is all still located in the

site development footprint, which was the subject of the botanical survey and fauna habitat

assessment, and follow-up botanical survey, and thus no new vegetation clearance is

proposed.

Comment - Further explanation of the results from the habitat assessment is required. The

supporting report does not describe how fauna habitat was assessed nor defines the criteria for

the assessment. Include these pieces of information in the DPEMP Supplement.

Response - The survey methodology used for the fauna habitat assessment was provided to

the PCAB, and PCAB determined it to be sufficient for the purpose of the DPEMP (Appendix 4).

CBM was advised that no further surveys would be required on site.

Comment - It is recommended that vegetation clearance or other construction activities

involving acoustic disturbance within 500m or within 1000m line of sight be avoided during

WTE breeding season-unless an activity status check by a suitably qualified expert at the

appropriate time confirms that the nest is not in use during that season.

Response – HRCM agrees to undertake a nest activity survey on the three nearby WTE nests at

the beginning of the breeding season, and this will inform activities to be undertaken on site

during construction.

Comment - It is recommended that drill site operations be conducted outside of the WTE

breeding season (July-Feb) to minimise any impacts to nest #1112. This should be

complemented by the above monitoring program.



Response – The current exploration drilling program has been approved by MRT following the

special values assessment performed by Forestry Tasmania of the target drill hole locations.

Comment - It is recommended that HCM takes measures to avoid disturbing devil breeding (eg.

conducting a pre-clearance survey by a suitably qualified expert) prior to disturbing a potential

den. PCAB requires that a pre-clearance search of mature hollow bearing trees be conducted by

a suitably qualified expert. The survey should include a check of mature trees for hollows that

may provide potential nests for masked owls and grey goshawks.

Response – HRCM agree to undertake a pre-clearance survey of any vegetation prior to

clearance.

Comment - Any clearance of the threatened Eucalyptus amygdalina forest and woodland on

sandstone (DAS) should be avoided wherever practicable.

Response – No clearance of DAS is proposed in the current development plans.

Comment - Development of the Fire Management Plan outlined in the Exec Summary states

that the plan will be reviewed by the Tasmanian Fire Service (TFS) and the Tasmanian Parks

and Wildlife Service (TPWS). This contradicts Chapter 4 where it is stated that only the TFS will

be consulted. Clarify in the DPEMP Supplement which parties will be involved in the review

process. PCAB recommends that Forestry Tasmania participate in the review given it is the

primary manager of the surrounding land.

Response – The Fire Management Plan will be reviewed by the TFS and Forestry Tasmania

prior to implementation. Forestry Tasmania will be contracted to undertake fire management

services on the subject land, which will formalised through a Forest Lease agreement.

3.3 EPA division

Comment - The mine air ventilation system is also expected to be a source of dust emissions.



HCM should discuss in the DPEMP Supplement the likelihood of dust emissions via this route

and how it intends to limit these.

Response – Mining engineers presently designing the ventilation system advise that ‘dust

management will be addressed through suppression systems such as water sprays on

equipment, and balancing ventilation air quantities and velocities to decrease the movement

of dust. There is also the potential for filters to be put on ventilation shafts if deemed

necessary.” The water used for dust suppression will increase the moisture level in the

extracted coal and thus be transferred to the surface in the coal, and run off into the

underground mine workings. Any net mine water discharge will be pumped to the

settling/retention basins prior to release to the environment.

Comment - While the potential for AMD is expected to be low this must be verified by mine

water analysis and Acid Base Accounting. Salinity is more likely to be an issue and can be

determined by leach testing. Provide and discuss these analyses in the DPEMP Supplement.

Response - A detailed Acid and Metalliferous Drainage (AMD) assessment on the interburden

to be removed during mine development has been undertaken by GHD and is attached as

Appendix 6. A total of 27 samples were taken from drill holes VR004 and VR006 of material

above, in and below the target coal seam. This sample quantity exceeds the QLD EPA’s

sampling guidelines based on the volume of interburden to be removed. The samples

underwent NAG and NAPP testing, as well as a range of testing for leachable and total metal

and cation content. The carbonaceous mudstone and coal samples also underwent chromium

reducible sulphur analysis to exclude non-acid-forming (NAF) organic sulphur from sulphide

sulphur. All samples had an acid neutralising capacity to maximum potential acidity ratio of

greater than 2, which indicates that for all samples acid generation is unlikely, and the overall

risk of AMD is low.

52 samples of coal from the current drilling program have been assayed for sulphur content.

The average sulphur content for F seam coal is 0.30% with a 95% upper confidence limit of

0.39%. These results are considered low levels in terms of AMD risk, and provide a correlation

of the results of NAG and NAPP testing over a wider area of the proposed mine lease.

In the unlikely event that PAF or PAF-LC material is encountered during initial mine



development, an AMD Contingency Management Plan (AMD-CMP) has been developed to

provide best practice environmental management control measures to mitigate any associated

environmental impacts to satisfactory levels. This AMD-CMP is attached as Appendix 13.

Targeted locations for implementation of precautionary AMD control measures include:

The mine adit (Including temporary suspect PAF holding areas (above and below ground);

Designated PAF / PAF-LC material disposal areas (should the need arise);

General waste rock dump and associated drainage / sediment retention basin, located at the disused quarry site; and

Sediment retention basins and associated water improvement system, located to the north of the mine adit and associated above ground infrastructure.

A combination of suspect PAF avoidance, material characterisation, selective handling

procedures and passive / active AMD management measures have been developed for the

site. These are linked to laboratory testing of waste rock (AMD characterisation) and

continuous pH / alkalinity monitoring of surface and mine water. This provides multiple lines of

defence against potential oxidation of PAF material (and subsequent potential AMD

development), should any such material be encountered.

Comment - Location of the intended coal stockpile must be provided, along with an estimate of

dimensions and intended management measures. HCM should also clarify whether it intends to

include development of the coal stockpile with its application for a new coal loading facility and

rail spur.

Response – The intended coal stockpile will be included in the subsequent development

application addressing the coal loading facility and rail spur. The draft plan is attached as

drawing C7-02 Rail site plan. A 20,000 tonne stockpile is proposed, approximately 200m long

by 20m wide and 3m high. The key management measures relate to water runoff from the coal

stockpile. This water will be diverted to a sediment/catchment basin where the coal fines will

be allowed to settle, and then to a constructed wetland to allow total petroleum hydrocarbons

remediation. The water will then be reticulated via a grassed swale to the existing farm dam

located north of the proposed stockpile. Atmospheric dust is not considered an environmental

impact because the stockpile will be replenished on average every week, and the coal will

retain moisture from the mining dust suppression process.



Comment - HCM should identify Forestry Tasmania as a key stakeholder.

Response – Agreed.

Comment - HCM must confirm the route of transmission lines to the proposed mine site and

area of vegetation to be cleared. Provide a drawing of the intended power easement (including

transmission infrastructure). Note that HCM will need to conduct an assessment of natural

values associated with the forest marked for clearing to establish the power easement.

Response - The route of distribution/transmission lines to the site has been confirmed by

Aurora and Transend, and is shown in Appendix 8, drawing E2-01 Electrical Network Supply. A

12 metre wide easement is required for the 22kV overhead line route from the Esk Hwy to

proposed development site. This route intercepts tower 95 of the 110kV transmission line, and

a substation will be installed at the base of tower 95.

A Natural Values Report was prepared for the area of the proposed easements, and is attached

as Appendix 5. It indicated that no threatened flora or fauna was identified within this area.

Subsequently PCAB has advised that this desktop survey will suffice, given that no threatened

species were identified.

Comment - The land identified for irrigation [drawings C3-01, C3-02 & C3-03) of wastewater

from the package treatment plant does not appear to be appropriate with respect to soil type,

slope and area. HCM should review and revise its irrigation plan with due regard to expected

treatment performance of the package treatment plant and the need to protect water quality

of ground and surface waters.

Response – Based on the results of the Geotechnical Assessment, which confirms the

unsuitability for irrigation of the treated effluent on site, this will now be dosed into the

sediment/retention basins, and will ultimately be discharged to the receiving environment.

The domestic waste water management strategy is outlined in section 4 of the Water

Management Plan (WMP) (Appendix 11).



Comment - Ongoing dust suppression along Valley Rd will be required as per Traffic Impact

Assessment recommendation. HCM should note that a water tanker will need to be available

on demand and not just limited to the summer months.

HRCM has committed to upgrading Valley Rd to 6.2 metre wide sealed road from the Esk Hwy

intersection to the mine access road. This will alleviate the requirement for ongoing dust

suppression along Valley Rd.

Comment – Commitments 1 and 6 are limited to desk top reviews. Reports recommend more

detailed work be undertaken (Commitments 1 and 6). These additional investigations must be

conducted now and results discussed via the DPEMP Supplement, particularly with respect to

how the results affect the present siting of major infrastructure such as water improvement

ponds and catchment dam. See also comments at DIER – Mineral Resources Tasmania. Note

that a conceptual water balance is required.

Refer to section 2.2.3 which contains a similar comment and response in regards to

groundwater, and section 3.4 which details the further geotechnical investigations undertaken.

Comment - EPA Division is not supportive of first wash diversion from the proposed coal loading

area. Coal handling is not expected to cease during rainfall events. Coal fines will be contained

within larger coal lumps and flushed depending on rainfall intensity, duration etc. HCM should

review this aspect of its intended water management strategy and if necessary include a

revised measure to treat stormwater flow from the coal loading area in the DPEMP

Supplement.

Response – The proposed water management strategy has been revised to remove the first

wash diversion from the coal loading area. This will result in all surface water runoff from this

area to be diverted through the sediment/retention basins.

A WMP has been developed to ensure that mine construction and operational activities will

not result in unacceptable impacts on surface waters and the groundwater system, as well as

groundwater dependant ecosystems and downstream water users. It ensures that all water



leaving the mine site is disposed via the designated discharge point, complies with (proposed)

license discharge limits, is managed according to relevant statutory requirements and is

regularly monitored to ensure compliance with the above.

The WMP includes the conceptual design of water management infrastructure.

Sediment/retention basins are the key process for ensuring all water discharged from the site

is of a minimum quality standard as to not result in an unacceptable impact on the receiving

environment. The basin design considered the catchment size and slope, rainfall intensity and

its susceptibility for soil loss during construction, as well as the expected coal dust on Site from

aboveground coal handling and from underground workings. It also considered the potential

for net groundwater discharge from the underground workings during normal operations. The

Stage 2 Hydrogeological Review determined the groundwater encountered to be of high

quality, with the potential for it to achieve the drinking water environmental value. The

review indicated that groundwater would generally have the following properties:

• Electrical conductivity <1,000 μS/cm;

• pH ranges from 7.2 to 7.5;

• All metals analysed, except for iron (0.305 mg/L) and manganese (0.495 mg/L), were below ANZECC & ARMCANZ (2000) trigger values for long-term irrigation (LTV), livestock water supply and freshwater aquatic ecosystems (FAE95%) and NHMRC 2004 Australian Drinking Water guidelines (ADWG);

• Low sulphate levels;

Thus, no improvement of this fraction of the overall water balance was considered to be

necessary, although if in the unlikely case that low quality groundwater is encountered it can

be retained for reuse or isolated, collected and pumped to the retention basins for treatment.

Based on these design considerations, the total required capacity is of the basins is 486m3. For

the purpose of utility water supply the total water capacity is increased to 1ML to maximise

the water storage capacity on site. This in turn increases the detention times, and the

efficiency of the system is greatly enhanced. Rather than a single pond as tested as example 1

in the WMP, the likely design will incorporate at least 3 basins in sequence. Example 2 details

the performance of a multiple basin system; basin 1 being 0.25ML, basin 2 being 0.5ML and



basin 3 being 0.25ML. While the settling efficiency is similar to a single basin of the same

volume, the majority of the transported sediment and coal dust is removed in the first basin,

whilst the small amount of suspended clays required the longer retention times produced by

the greater capacity and volume of the total system.

The WMP also includes a mine water balance calculation, incorporating modelling of the

available onsite water storage during ongoing mining operations. The main water

requirements for the site include underground process water, domestic water, dust mitigation

water, fire fighting water and general site water. The main water inflow sources include net

excess groundwater from mine workings, stormwater runoff from site hardstand areas, rainfall

from building roofs and potable water supply from Cardiff Creek. Overall, the modelling

determined that based on the last 112 years of rainfall data, and assuming the 1ML of storage

capacity, there would be a net water discharge to the receiving environment most months,

with the average monthly discharge volume of 0.49ML.

The Stage 2 Hydrogeological Review (GHD, 2012), found that inflows using stochastic

distribution model gave steady-state 90th percentile of 1.5 L/s consistent with those of a simple

calibrated model. The underground water usage is expected to be 30ML per year or

approximately 1 L/s, thus the net excess groundwater is expected to be very minimal, at less

than 1 L/s (0.65 L/s). The modelling considered this scenario, and determined that this would

increase the net monthly inflow of water to the basins by 1.3 ML, and would increase the

average monthly discharge to 1.66ML (0.63 L/s). Given that indicative basin design flow in

Section 3.2 was the 1 year ARI peak flow of 65 L/s which is a two orders of magnitude greater

than the net groundwater inflow to the basins, it can be said with great confidence that if the

basin requirements are met, a much larger flow can be pumped from underground and

sediment removal efficiencies will be maintained. The modelling also considered a scenario

whereby there is a net shortfall of groundwater for operational use underground. It was

determined that the basins would be able to supply on average approximately 0.44 ML per

month, or 0.17 L/s. If this was inadequate, additional water may be required from external

supplies.



3.4 DIER - Mineral Resources Tasmania (MRT)

Comment - MRT notes that the mining plan is outlined as a “strategy” and is not a specific plan.

A general description of the bord and pillar mining method is provided. This section lacks the

detail that is normally informed by resource definition drilling.

In conjunction with ongoing resource drilling and evaluation, HRCM has engaged additional

mining, geotechnical and geological expertise to take the geological modelling and mine

planning to the level required for mining to commence. HRCM will provide this information to

MRT through the Mining Lease application process.

Comment - Within the Waste section it is stated that “there will be minimal waste interburden

rock, and the coal is of sufficient quality that all extracted material is transported off-site

without any processing or washing onsite.” This statement cannot yet be made as there has

been no characterisation of interburden and not enough drilling has been done to properly

understand the quantity of interburden or the quality of the coal. HCM must characterise the

nature of the interburden and in the DPEMP Supplement discuss what the results mean in

terms of measures to manage this material. A revised estimate of the quantity of interburden

must also be provided.

Response – Section 3.3 details the AMD assessment completed on the waste rock to be

removed during initial mine development. While the mine planning process has not been

finalised, design of the initial mine development has been completed to enable a more

accurate calculation of the volume of interburden to be stored, which is approximately 24,400

m3. Although the initial mine development will primarily be through the coal seam and the

coal will be removed from site as a saleable product, some waste rock above or below the

seam will be excavated during development, and some waste rock will be generated from

within the seams or in localised areas where the seam is less than the drive height. Once the F

seam has a sufficient working height for continuous miner operation, only a small proportion

of the total extracted material will be waste rock (695,000 tonnes of waste rock in a total

extracted material volume of 13,368,000 tonnes over the 15 years expected mine life). This

volume of waste rock will be stored underground in areas where coal has already been



removed.

A Waste Rock Management Plan (WRMP) for the interburden mined during the Initial

development has been developed and is attached as Appendix 12. It outlines the strategy for

the emplacement of waste rock in the nearby Forestry Tasmania quarry known as Abraham’s

Pit. The pit has sufficient capacity to accommodate all the interburden or waste rock likely to

be produced during the Initial development phase. The dump site is an abandoned section of

the quarry located east of the current operations, and has sparse natural revegetation cover

that has grown in the approximately 20-30 years since it was operational. Only non-hazardous,

Non-Acid Forming (NAF) and Acid Consuming Non-Acid Forming (AC-NAF) material will be

disposed of at the Waste Rock Dump (WRD), which will be constructed from the bottom up,

initially with a series of batters and benches to aid run-off and minimise erosion. Contour

drains and side berms will be installed at the toe of each batter and will direct runoff from

north to south, to encourage slow run-off infiltration. Drains steeper than 2% will be rock

lined to a depth of 2.5 times the maximum rock diameter.

Water will be collected from the most southern extent of the WRD and directed to a sediment

pond located at the south-east of the site. It is anticipated that any potential runoff increase

would result from increased grades and not be associated with decreased site permeability.

Following the settling of any sediment, excess water will be released into the existing drainage

system at the south east of the site. The sediment pond will be subject to monthly water

quality sampling for a period of 12 months following the completion of the disposal activities.

Also following the completion of disposal activities, the WRD will be rehabilitated, ensuring the

following objectives are met:

Where practical, reshape all disturbed areas so that they are stable and conform to existing landforms;

Establish an adequately drained landscape;

Apply cover and final topsoil layers as necessary;

Revegetate the disturbed area with appropriate ocal plant species,

Control erosion through appropriate drainage control and revegetation; and

Monitor and manage the rehabilitated areas until the vegetation is self-sustaining or acceptable to regulatory authorities and the local community.



Comment - Estimated mine production is based upon incomplete exploration results and a

conceptual mine plan. Refine/ validate mine production figures by continuing and completing

intended drill program (and associated exploration study) to prove the coal resource.

Response – Refer to the first MRT comment above. This process is ongoing, and will be made

available to MRT through the Mining Lease application process.

Comment - The first two paragraphs of the Land Stability section refer to a Desktop Review of

Land Stability [DPEMP Appendix 10]. The desktop review is insufficient for inclusion in a DPEMP

for a proposal of this nature. A thorough onsite investigation is required to be undertaken by a

suitable qualified expert in slope stability assessments of this scale. The geotechnical report

must investigate potential hazards and demonstrate that [the proponent] HCM understands

these and that the risks can be satisfactorily managed. It is contemporary practice for

geotechnical reports to include a resume outlining the qualifications and relevant experience of

the practitioner(s) involved. The proponent should have the geotechnical report peer-reviewed

before inclusion into the DPEMP Supplement and subsequent submission to MRT and EPA for

their consideration. Any geotechnical investigation must adequately identify and assess all

potential risks. HCM must use the results of further geotechnical investigations to confirm the

intended locations of key infrastructure, such as water improvement ponds and/ or catchment

dam. In the event that further geotechnical studies show that key infrastructure must be

relocated due to stability concerns, then HCM must submit appropriate details and drawings to

indicate the revised locations. Additional assessment of natural values of the proposed

activity’s site may be required in the case where major infrastructure is relocated as a

consequence of further geotechnical studies.

Response – A geotechnical assessment has been completed, as outlined in Commitment 1 in

the DPEMP. This assessment included a geotechnical site investigation and in accordance with

the following standards and guidelines:

Australian Geomechanics Society (2007) Landslide Risk Management.

Australian Geomechanics 42(1) March 2007.

Standards Australia (1993) AS1726-Geotechnical Site Investigations

Standards Australia (1997) AS1289.5.2.1 – Soil Testing for Engineering Purposes



Standards Australia (2004) AS/NZS4360 - Risk Management

Standards Australia (1997) AS3798 “Guidelines for Earthworks on commercial and residential subdivision”

Pit testing and a landslide risk assessment was completed at each site of proposed

infrastructure. Risk mitigation options were developed, resulting in a residual risk rating for

each site. The outcome of this process has resulted to amendments in three key areas of the

aboveground infrastructure;

Removal of water take off holding dam from area of pit 12.

The initially proposed holding dam is not necessary, as the holding capacity for potable water

can be achieved with tanks. Additional disturbance of the talus in this area is not necessary,

and additional tanks are ultimately flexible in terms of capacity and location.

Moving of the proposed office area from the area investigated via pit 9 and pit 10 to

the area of Adit 1 being underlain by Triassic sandstone.

As confirmed by the assessment Author, the amendments to the site plan are consistent with

this recommendation. Furthermore, the peer review also makes note of the difficulties in

providing engineering solutions to mitigate risks of debris flows, noting that the descriptor of

risk consequence should be considered as major. Thus the recommendation to move any

major infrastructure out of this area is supported.

Locating effluent dams on the flat down slope area below 7 degrees and location of dam

to the area of pit 4.

As confirmed by the assessment Author, the sediment/retention basins are located in the

areas investigated as pit 4 and pit 6. The advice that, dams by virtue of their function, elevate

the risk to site stability is understood, and even though the ACDC process will not be required,

further geotechnical investigation is necessary to determine the final design of the basins. Yet,

while further investigation is necessary, and may result in the final location of the basins

changing slightly, the entire flat terrace area at the northern extents of the site, which is below

7 degrees, is within the development footprint and was subject to all site environmental

investigations and reports undertaken to date. These changes are reflected on the updated

Site Plan, drawing C3-01 in Appendix 8.



The geotechnical assessment has been independently peer reviewed by Graham Granger from

GHD, and this review is attached as Appendix 10. Graham notes that “the Strata team have

done a good job, which is appropriate within the scope of the project. The report was of a high

standard”. Graham also notes that while the assessment is a preliminary or feasibility stage

investigation, it is suitable for the current stage of the project. He notes “in a project of this

scale, the geotechnical investigations are often completed in a two stage approach, the initial

investigation to inform site selection for the proposed infrastructure components and

sometimes their concept design (suitable for development applications), and a further more

targeted investigation to inform detailed design and construction.

Considering that a landslide risk assessment has been undertaken at each site of proposed

aboveground infrastructure, and changes have been made to the location of some items of

infrastructure while still within the development footprint, as well as Graham Granger’s view

that the work completed is appropriate within the scope of the project, HRCM are of the

opinion that this comment has been adequately addressed. It recognises the need for further

investigations prior to detailed design and construction, and is currently developing a scope of

works for further investigation, based on the recommendations for further works from the

Strata Geotechnical Investigation and the peer review

Comment - Commitment 5 – development of a Water Management Plan. This must be

completed and incorporated into the DPEMP Supplement so that the proposed activity can be

properly assessed based on the results and associated management measures. The Water

Management Plan underpins the site water balance, conditions for wastewater irrigation and

subsequent engineering designs (water improvement ponds, culverts, catchment dam, pump

sizing for dewatering…).

Refer to section 3.3.

Comment - Commitment 6 – further hydrogeological assessments. This work must be


properly assessed based on the results and associated management measures.

Response – Refer to section 2.2.3.



Comment - Commitment 9 – interburden should be properly characterised and quantified

during resource drilling so that waste management strategies can be finalised and assessed in

the DPEMP Supplement.

Response – Refer to the previous MRT comment and response in regards to interburden.

Comment - Commitment 12 – development of a Special Values Management Plan for

threatened fauna species. This plan must be completed and incorporated into the DPEMP

Supplement so that the proposed activity can be properly assessed.

Response - HRCM questions why MRT require this to be prepared for the supplement, when

the EPA and DPIPWE threatened species unit has not requested this information at this stage.

HRCM have committed to providing this information prior to the commencement of onsite

construction activities.

Comment - Commitment 19 – development of a traffic management plan. This plan must be


properly assessed. Also refer to comments under DIER – Roads and Traffic Division and Forestry

Tasmania.

Response - HRCM questions why MRT require this to be prepared for the supplement, when

DIER have not requested this information at this stage. HRCM have committed to providing

this information prior to the commencement of onsite construction activities.

Comment - Groundwater chemistry and AMD assessment (geochemistry) needs to be done and

included in the DPEMP Supplement for assessment. This relates to Commitment 22.

Response – Refer to a similar comment and response in section 3.3.

Comment - Commitment 23 – development of Mine Closure Plan; has open-ended timing. This



commitment should be within the first 2 years of commencement. HCM must provide a

preliminary Mine Closure Plan in the DPEMP Supplement. The plan must outline the intended

program for decommission of site activities and assets and include cost estimates for these.

Costing information must be included for decommission of major infrastructure, whether these

assets are dismantled and relocated or modified and retained onsite.

Response – HRCM will commit to developing the Mine Closure Plan within the first 2 years of

commencement. HRCM questions why MRT require a preliminary Mine Closure Plan in the

DPEMP Supplement, when section 6 of the DPEMP provides an overview of the rehabilitation

and decommissioning of the site after mine closure. HRCM will provide this information to

MRT through the Mining Lease application process.

3.5 Forestry Tasmania

Comment - Commitment 17 - Forestry Tasmania (FT) manages fire on State Forest, as per the

Forestry Act 1920. HCM must include FT in any proposed fire mitigation works in the

surrounding State Forest vegetation or during the preparation of a Fire Management Plan for

non structural areas. The Tasmanian Fire Service must be consulted for structural fire

mitigation within the lease area.

Response – HRCM agrees, and discussions have progressed with FT for the provision of fire

management services during mine operation.

Comment - FT notes that HCM will need to establish a license agreement with FT during the

assessment process conducted by the Assessments Committee for Dam Construction for any

dams constructed on State Forest. Offsets will need to be established for loss of production

forest and reserved areas, as per FT’s dams on State Forest policy.

Response – As detailed in the attached WMP, the total capacity of the sediment/retention

basins is 1ML, which is under the threshold for requiring Assessments Committee for Dam

Construction approval.



Comment - Commitment 9 - FT confirms initial discussions have occurred with HCM concerning

storage/ disposal of waste rock within FT quarries in the Valley Rd area. FT notes that it will

only consider waste rock/ burden for storage/ disposal in this manner if the material is shown

to be free of Phytophthora cinnamomi. HCM should note that the EPA Division will need to

sight evidence of any agreement between FT and HCM concerning storage/ disposal of waste

rock/ burden in FT managed quarries or borrow pits. This will need to occur prior to issue of any

final approval of the proposed activity.

Response – A letter from Forestry Tasmania is attached as Appendix 9, and outlines the agreed

outcomes in regards to FT’s comments to the DPEMP. FT confirms that it is in support of the

strategy to use of Abraham’s Pit to store waste rock from the initial mine development

providing the following:

• The material meets EPA guidelines for storage

• That the material is suitable for use in rehabilitation purposes

• It will not cause future environmental issues on State Forest or to other adjoining neighbours.

• EPA to provide confirmation to FT that any MD assessment of the interburden material meets the required environmental standard to proposed used on State Forest.

HRCM recognise that EPA will review the WRMP to ensure that these comments are met prior

to approval.

Comment - FT confirms it’s held preliminary discussions with HRCM concerning potential license

agreements for sections of State Forest for use as visual screening. No formal agreement has

been reached. FT notes that the map referred to in drawing EN2-04 does not reflect the present

land management practices on State Forest in this area (see comments below at EN2-04 and

EN2-05).

Response – HRCM and FT have agreed that a Forest Lease is the appropriate mechanism to

effectively expand the existing informal reserve in and around the Site, as shown in dwg C2-05.

This allows the area managed for conservation within the lease, when coupled to the existing

informal reserve, to form part of the threatened fauna impact mitigation strategy for the

Project.



Comment - FT does not support the proposed GHD Traffic Management Plan. Valley Rd is

classed as a public road and therefore must provide safe access for all road users, not rely on

radio communication. Refer also MRT comment above.

Response – HRCM has confirmed its commitment to seal Valley Rd to a pavement width of

6.2m between the Esk Hwy and the Project Site entrance, and to provide appropriate road

warning signage as required by DIER and relevant Australian Standards. FT has confirmed that

these commitments will allow for the safe use of this road to other road users.

Comment - FT will require the Valley Rd surface to be sealed to a pavement width of 6.2m

(excluding shoulder width) to cater for the safe passage of the forecast volume of heavy traffic

and other road users.

Response – refer response above.

Comment - FT requests that HCM confirm in the DPEMP Supplement that mine entrances will

be capped during rehabilitation.

Response – HRCM can confirm that this will occur.

3.6 DIER Roads and Traffic Division

Comment - The TIA indicates likely on-site employee numbers of between 40 – 50 staff and

notes that most would travel to / from south of the site. This could potentially generate an

increase in the number of right turning traffic from Esk Main Road into Valley Road. The TIA

however does not provide any information on turning movements at the Esk Main Road /

Valley Road junction. Review and include these details in the DPEMP Supplement.

Response – As indicated in the DPEMP, the proposed rail spur, coal stockpile and Esk

Hwy/Valley Rd intersection works will be the subject of a subsequent Development Application

to be submitted to Break O’Day Council. The draft plan is shown in drawing C7-02.

Included are the proposed changes to the Esk Hwy/Valley Rd intersection, which involve the



widening of the bridge to incorporate a slip lane, allowing traffic to pass freely in the event of

right turning traffic from Esk Hwy into Valley Rd. Yet turn right traffic is expected to be

minimal, given that a car park for underground staff is proposed south of the coal stockpile

area, and a bus will ferry workers to and from the mine site and the car park at the beginning

and end of each shift, via the proposed underpass.

Comment - Roads & Traffic Division (R&TD) requires clarification about projected turn volumes

at the Esk Main Road / Valley Road junction, particularly whether or not haulage vehicles (HVs)

being used to transport coal from the mine to the stockpile will be solely for this purpose and

when not in operation will be parked at the mine site and HV drivers commute via light vehicle

at start /end of shifts. Alternatively, will HVs be using the junction at start / end of shifts due to

them being garaged elsewhere outside operating times? Please clarify.

Response - In addition to the previous response, all haulage vehicles will utilise the proposed

Esk Hwy underpass when transporting coal from the mine site to the stockpile. They will be

used entirely for coal haulage onsite, and will be stored at the mine site at the end of each

shift. All staff will be using the Esk Hwy/Valley Rd intersection, and it is expected that two

thirds of the staff will be travelling from the west, and one third will be travelling from the

east. Additionally, the majority of non-staff traffic to the mine site is expected from the west.

The total number of turn right movements from Esk Hwy onto Valley Rd (and thus turn left

movements from Valley Rd onto Esk Hwy) is expected to be about 70 per day, while the total

number of turn left movements from Esk Hwy onto Valley Rd (and thus turn right movements

from Valley Rd onto Esk Hwy) is expected to be about 30 per day.

Comment - Austroads Guide to Road Design Part 4A suggests that a BAR basic right turn facility

should be provided as a minimum treatment. However until HCM can clarify/ confirm that

traffic using the Esk Main Road / Valley Road junction will be limited to mostly light vehicles

and occasional HV use, R&TD cannot make an assessment on whether provision of such a

facility may or may not be required. Please elaborate about this in the DPEMP Supplement.

Response – HRCM has agreed with DIER to stage theupgrade of the Valley Rd intersection

suitable for construction and initiation of the mine, with a new BAR basic right turn being



established in line with the mine moving from initiation to full production.

Comment - R&TD does not support use of isolated regulatory 50km/h speed control in the

vicinity of the mine access as mentioned in the TIA. However provision of 40km/h regulatory

speed signs for vehicles exceeding 10t may be considered over the full length of the haulage

route along Valley Road. HCM should note that provision of this and any permanent warning

signs (i.e. trucks turning) will require DIER approval under the Traffic Act 1925.

Response – HRCM will liaise with DIER R&TD to resolve and agree upon an acceptable speed

limit over Valley Rd (between Esk Hwy and the mine entrance roads) during the detailed

engineering phase of the project.

Comment - R&TD notes that provisions to transport the stockpiled coal to the Fingal rail line

are being explored separately to this assessment. This will require assessment by DIER to

ensure that the design does not adversely impact on traffic safety and operation on the Esk

main Road.

Response – DIER will be required to assess this aspect of the mine development through a

subsequent Development Approval for the proposed rail spur and coal loading facility.

3.7 Supplement Revision 2 comments

Comment – As requested previously please provide EPA Division with the most contemporary

draft of the mine plan which will enable EPA Division to ascertain, among other matters, the

intended path(s) of initial mine development, amounts of rock/ coal likely to be encountered

and how the volume of interburden has been estimated.

And

Comment - Given EPA Division's understanding that the path (location, length) of the initial

drive has altered from the original and that there may now actually be two drives, it is vital

that Hardrock provide EPA Division with (at least) further details of drive development outlined

above, namely:



Figures/ diagrams that show precisely the intended path(s) of drives, their coordinates,

dimensions and likely geology encountered. Locations of existing adjts should be clearly marked

Map locations of all drill holes that show how the drilling program relates spatialIy to the

intended drives. Indicate on map which drill cores have been assayed for AMD parameters

Response – Attached in Appendix 8 are the following drawings showing in detail the initial

mine development, the associated geology and relevant drillhole information:

CR HRCM 0011 - Outline of Mine Plan with Initial Development

CR HRCM 0012 - Initial Development Plan Showing Geology

CR HRCM 0013 - Initial Development Plan Showing Drillhole Information

Drawing CR HRCM 0011 shows the extent of the initial development into context relative to

the old Valley Mine surface area and the proposed underground layout for the Fingal Tier

Project. CR HRCM 0012 is a larger scale plan that shows in more detail the proposed initial

development, its limits with coordinates and possible geology that may be encountered.

Salient points are:

The mine entries are planned to utilise the approximate sites of the old Valley Mine Adits. The precise position of the entries will be where an acceptable rockhead can be found to commence the roadways.

The eastern entry will be a rectangular profile, 6m wide and approximately 4m high. It will house a 1200mm wide conveyor that is suspended from the roof, mine services including power, process water and pumping services. It will be the access roadway for men and materials and act as the ventilation intake.

The western entry will be a rectangular profile, 6m wide and approximately 3.5m high. Its function is to act as the ventilation return, and operates as a second means of egress from the mine.

Normal mine development will commence at about 550m in from the mine portals and is where continuous miners will begin to extract an appropriate working section and create a run of mine (ROM) product.

The coordinates of interest are shown on Plan CR HRCM012 and utilise coordinate system GDA1994 Zone 55.

The RL of the start and finish positions are known, meaning that the initial development is in fact a special exercise in the vertical plane.

The precise nature of geological conditions cannot be determined from exploration programs,

however sufficient information is available to conclude that:



There is an adequate working section at the start and end of the initial development,

Either a seam dislocating fault, an intrusion or a seam deterioration was encountered in the old valley mines, and

There is the possibility of a localised seam thinning, splitting or washout which could be up to 200m wide.

Details about how interburden volume has been calculated and level of confidence in this

figure. Please clarify the expected upper limit of interburden and whether the waste rock dump

will/ can be engineered to receive (up to) this volume of material.

Response - In calculating the volume of interburden to be encountered during initial mine

development, the following assumptions were made:

1. The working section is continuous in coal bearing strata except where there is a fault or seam washout. Modelled seam thicknesses are shown on plan CR HRCM 0012.

2. Any old roadway encountered was assumed to be collapsed and contain bulked up waste material.

3. The coal section is mined first with the roadheader but the top 250mm of coal material is assumed to be the base of the interburden and is lost to interburden.

4. Interburden is mined discreetly by the roadheader.

5. The roadway dimensions are:

- Conveyor Roadway – 6m wide by 4m high,

- Return Roadway – 6m wide by 3.5m high,

- Connecting roads or cut throughs – 6m wide by 2.5m high

6. Material densities are:

- Coal – 1.5 in situ, 1.0 as mined

- Rock – 2.1 in situ, 1.5 as mined

7. Compaction Factors are:

- Dozer 10%

- Compactor 20%

This allowed the calculation of interburden for three different scenarios, being:

Best case - the drives encounter a single fault which is negotiated by a 50m section of roadway driven completely in material that is the equivalent of interburden;

Worst case - The drives encounter a seam deterioration or washout 200m long with material that is the equivalent of interburden;

Worst Case plus temporary storage area – As per worst case including the need to



drive a length of roadway to temporarily store PAF and PAF-LC interburden

Table 1. Interburden volume calculations for initial mine development

As shown above, the worst case estimate of interburden is 24,400 m3 as a fully compacted fill.

The volumetric capacity of the waste dump preliminary design is 38,500m3 as per drawing

3867.008-SK05 in the WRMP. Thus, the capacity of the proposed WRD is significantly larger

than the worst case estimate of interburden, and ensures that increase in interburden volumes

extracted due to unforseen events can be managed appropriately through the current WRMP.

Evidence to show that the core sample (from VR004) assayed for AMD parameters is highly

likely to represent the same rock type(s) expected to be intercepted during development of

any/all mine drives.

Response - Drill holes VR004 and VR006 are in a series of six drill holes that cored to coal

bearing sequence of interest, and in all six holes coal seams and interburden strata have been

correlated. Ken Morrison, consultant geologist for HRCM advises:

“Within the Upper Triassic Coal Measures of the Tasmania Basin (Fingal Valley, Midlands,

Derwent Valley) the rocks can be lumped into 4 groups; lithic sandstone, grey mudstone,

carbonaceous mudstone and coal, including dirt bands of both fluvial sediment and volcanic



ashfall origin. The VR series drilling has encountered all 4 rock type groups in every hole so far

and the logs correlate well with the previous Department of Mines drilling so we can be

confident that a set of AMD sampling around F and G seams anywhere within the deposit will

be representative of the Valley Road resource”

In all six drill holes, core samples of coal sections and thin stone band materials have been

assayed for coal quality parameters including total sulphur content. The results are consistent

for all six drill holes and indicate low sulphur coal, average total content of 0.35% with a

standard deviation of 0.15%. Non coal strata sampled has an average total sulphur content of

0.09% with a standard deviation of 0.06%.



Figure 1 Drill hole fence diagram for VR001 – VR006

Comment - Are the groundwater models presented and discussed in the GHD report Stage 2

Hydrogeological Review considered as final? CBM's 5/4/2012 update forecast that a final

hydrogeological model would be available in August 2012.



Response – The groundwater model presented in the Stage 2 Hydrogeological Review

represents the area to be mined in the first 3 years of operations, which has informed the

development of a mine water balance and the conceptual design of the onsite water

infrastructure. Ongoing hydrogeological investigations (as per commitment 6) will continue to

inform the detailed design of mine dewatering infrastructure, but this model is considered as

appropriate for this impact assessment stage of the project.

Comment - Can the figure of 1.5L/s (groundwater inflow) be considered as a 'worst case' inflow

rate?

Response - Modelling of the Stage 1 development, using both a calibrated model and a

stochastic distribution model indicated similar steady-state inflows with a 90th percentile

inflow rate of 1.5 L/s.

Comment - GHD's report and/ or body of the Supp should include figures to show the location

of all drill holes/ bores used to conduct tests to develop groundwater models relative to the

intended mine lease and resource zone.

Response – Drawing CR HRCM 0013 shows the location of VR003 and VR006 drill holes used in

the development of the groundwater model in relation to the initial mine development.

Comment - In the absence of additional studies of the nature outlined in Section 7 of GH&D's

peer review report, no firm decisions/ conclusions can be made about the siting and detailed

design of the intended mine's water improvement system. It is recommended that Hardrock

engage geotech practitioners that are suitably qualified to undertake fundamental geotech

investigations (eg. Section 7 of GH&D's peer review report) the results of which will show

whether mine infrastructure can be safely sited at intended locations or not. Once again, MRT

has offered to assist Hardrock with the scope of its geotech studies.

Response – The proponent has committed to further geotechnical works to enable the

detailed design of aboveground infrastructure to occur, including the water improvement

infrastructure. In the unlikely event that these further geotechnical investigations determine



that the basins cannot be constructed in the area as shown in Drawing H4-01, a number of

options still exist to ensure that the required water improvement functions, as detailed the

conceptual designs in the WMP and AMD-CMP can be undertaken, including the lining of the

basins, or the replacement of in-ground basins with aboveground water tanks of the same

volumes. The following is a statement from Liam Dingemanse (BE (civil) MIEAUST) of CBM

Sutainable Design:

“Conceptual design of the water infrastructure undertaken to date indicates that the ponds

are likely to be shallow inter-linking ponds. The option exists for the ponds to be lined to

ensure impermeability of the structure to the subgrade. This lining can be in the form of a clay

or membrane liner, depending on potential settlement and slumping of the subgrade below

the ponds.

If the case arises that further geotechnical investigations indicate that an unacceptable

amount of movement in the subgrade could occur, ponds could be substituted with semi-

flexible tanks that can be positioned on the site, in areas with the least amount of movement.

Tanks have the benefit of much smaller physical footprint than an equivalent volume pond, as

well as allowing much flexibility in terms of placement on the site. The engineering of the

footing systems can be designed to mitigate significant instability risk, given the wide range of

footing options available, including piers and rock anchors if required. Given the geotechnical

information gained from the Geotechnical Investigation undertaken by Strata Geoscience and

Environmental, including the fact that the ponds are proposed to be located on relatively

gentle graded slopes, it is unlikely that a support system for the ponds or tanks could not be

designed for this site.

Structural investigation and design will occur in conjunction with results from the further

geotechnical investigations, and appropriate certification of the ultimate water retaining

structures will be obtained prior to construction.

Comment - EPA Division's Supp V1 comments (27/4/12) requested Hardrock to provide

information about where clay might be obtained and how much is required to construct liners

for all nominated ponds. Please provide this information in DPEMP Supp.

And



Hardrock should discuss what is to occur with materials excavated to develop its water

improvement ponds. What proportion of this material is likely to be reclaimed to use in pond

construction?

Response - The natural slope of the site in this area is approximately 4-6 degrees from

horizontal, so some cutting and filling will be required to achieve the required volume. Figure 2

gives a conceptual design of one of the basins. Due to the cutting, some of the volume of

water that will fill the finished basin will effectively be below ground level, thus enhancing

stability.

Given the predominance of clays in the topsoil and subsoil it is anticipated that much, if not all

of the material used to construct the basin will be derived from the site. If however during

detailed design further assessment concludes that the local material is unsuitable or additional

material is required, then the required material will be supplied externally and brought to site.

The volume of imported material required, if any, will be determined at the detailed design

stage.

Figure 2 Conceptual Sketch of Basin (based on SD 6-4 from Managing Urban Stormwater:



Soils and Construction “The Blue Book” Volume 1)

In the unlikely event that future assessments by geotechnical engineers recommend that the

basin walls and base need to be impervious for stability reasons, a geotextile liner can be easily

be incorporated in the detailed design of the ponds.

Comment - Hardrock should specify to what standard(s) it intends to construct all nominated

ponds, given that pond design will not be scrutinised by the DPIPWE's Assessment Committee

for Darn Construction (which applies the ANCOLD guidelines)

Response - The Blue Book (Volume 2E, Table 6.1) recommends that, for construction periods of

between 6 and 12 months, basins and spillways are designed to be structurally sound in the 1

in 50 year rainfall event. However given the basins will continue to be used during the

operational phase of the mine, the detailed design will ensure the embankment and spillway

are designed to be structurally sound in the 1 in 100 year event for the ‘sensitive’ receiving

environment. In addition, the basins will be designed and constructed in accordance with

DPIWE’s Guidelines for the Construction of Earth-Fill Dams (2008), Institute of Engineers

Australia’s Australian Rainfall and Runoff (1997), and the Tasmanian Government’s WSUD

Engineering Procedures for Stormwater Management in Tasmania (2012).

Comment - What is the maximum volume of interburden that the intended waste rock dump

site could realistically accommodate? Does this estimate align with the 'worst case' estimate of

interburden expected from the initial mine development?

Response – The volumetric capacity of the waste dump preliminary design is 38,500m3 as per

drawing 3867.008-SK05 in the WRMP.

As discussed in the WRMP an additional volume of around 10,000m3 could be gained if the

sediment basin was installed on the southern side of the gravel road at the southern extent of

the dump. The natural falls are in this direction so with minor works in the area near the

existing culvert, runoff from the dump can easily be diverted to the south east by a new

culvert. The full WRD footprint in this scenario is shown in drawing 3867.008-SK07.

No additional allowance has been made for any topsoil that could be stockpiled on the site and



add to the total volume available for waste rock. Therefore, a maximum volume of waste rock

that could be realistically accommodated at this site, whilst matching the fill in with the

existing landscape, will be in the vicinity of between 48,000 m3 and 50,000 m3.

As previously discussed, the worst case estimate of interburden is 24,400 m3 as a fully

compacted fill. Thus, the capacity of the proposed WRD is significantly larger than the worst

case estimate of interburden, and ensures that increase in interburden volumes extracted due

to unforseen events can be managed appropriately through the current WRMP.

Comment - Will interburden be in a physical form suitable to build stable/safe batters and

benches or will additional (crushing, screening) works be required prior to constructing the

WRD?

Response - It is expected that the interburden will be in a form which will allow the

construction of stable and safe batters described in the WRMP. Interburden waste rock will be

produced from excavation by a road header, and be comprised mainly of material less than

150mm in size. As such, it is expected that waste rock will be relatively well graded and be

removed from the underground workings in a form suitable for immediate disposal at the

WRD. Basic screening for excessive oversized material (rock diameters greater than 500mm)

will ensure material can be placed without the creation of unstable bridging and voids in the

dump. These large screened rocks can be stockpiled and used as a resource for the energy

dissipating rock lining of stormwater drop structures and sediment basin spillways. No other

crushing or screening works is anticipated prior to disposal. This basic screening will be

undertaken at the mine surface by an excavator, which will discretely pick out the large rocks

from the waste rock, prior to haulage to the WRD.

Comment - As per geotech investigations necessary to determine where the intended mine's

water improvement ponds can be safely located, adequate geotech field work is also required

at this stage (conducted by suitably qualified geotech person(s) to industry standards) to show

that geotech characteristics/ features are favourable for siting of the WRD's sediment basin

(~0.4ML) at the nominated location. That is, geotech investigations must show that the

sediment basin can be sited in the nominated location with a high degree of confidence (low



degree of environmental risk). If investigations show this is riot achievable, then another

suitable site for the basin must be identified and geotechnically proven.

And

Will the WRD sediment basin need lining? If so, is there a suitable clay resource available on

the lease for this purpose or will clay need to be imported? Please include an estimate of the

volume of clay that may be required.

Response - As discussed in the WRMP, the dump will provide a short term sediment generating

surface until rehabilitation is completed. The temporary sediment basin, with a total volume of

330m3, will be constructed to the south-east of the dump as described earlier in Section 4 of

this letter. This will allow the dump to shed runoff to the basin, which will be located at the

relative low-point of the surrounding terrain. Though detailed geotechnical analysis has not

been conducted for the site, the area is known to be an abandoned section of the Abraham’s

Pit quarry. Walking the site shows the surface layer is comprised of mainly clay, gravel and

rocks (refer to photos in Appendix A of the WRMP). As such it is likely that clay material will

need to be imported to the site to construct the basin. At the detailed design stage,

geotechnical analysis of the surrounding terrain, the proximity to the nearby gravel road, and

the properties of imported material will determine if the sediment basin will require lining.

Exfiltration of runoff through the basin, rather than via the spillway, is not an issue per se,

however the volume and amount of exfiltration and seepage will be taken into account to

ensure the stability of the structure is not compromised.

The WRD basin will be sized and embankments and spillways constructed according the same

standards identified in the earlier response relating to the mine site basins. The sediment basin

will be designed to naturally discharge to either the existing road culvert, or a new culvert,

thus combining with flows from road drainage. Although some revegetation has occurred in

the area, the impervious nature of the existing site will mean that the construction of the WRD

should not have a significant effect on the quantity of runoff.

Comment - Show where topsoil and other subsoil materials shipped to develop the WRD

sediment basin will be stored.

Response - As discussed in the WRMP, only a modest amount of topsoil is anticipated to be



sourced from the site. Due to the lack of topsoil onsite, no set storage area for stripped

materials has been set. If some of this resource is available, stripping and stockpiling of topsoil

will be conducted immediately before bulk waste rock will be placed. Topsoil can then be

stored:

Adjacent to construction areas which will be the first requiring rehabilitation;

In an area within the operational quarry area to the north, in agreement with Forestry Tasmania; or

To the south east of the dump, in the proximity of the alternative basin location

Stockpiles will also be constructed according to best practice as per Figure 3, which involves:

Placement of stockpiles at least 5m from existing vegetation, concentrated water flow, roads and hazard areas;

Constructed as low, flat, elongated mounds along the contour;

Less than 2m in height;

Construction of earth banks upslope to divert water around stockpiles; and

Installation of sediment fences 1 to 2m down slope of the stockpile.

Figure 3 Indicative Topsoil Stockpile (from SD 4-1 from Managing Urban Stormwater: Soils

and Construction “The Blue Book” Volume 1)

Comment - Is the WRD sediment basin expected to discharge? If so, how often, how much and



where? Given the 'sensitive' receiving environment, what discharge limits will be targeted for

the parameters listed in Table 4 (SEMF’s Waste Rock Management Plan)?

Response - The sediment basin is expected to discharge, and will achieve settling of the coarse

sediment fraction down to 0.02mm in the 5 day 85th percentile rainfall accumulation (as

discussed in the WRMP Section 3.2). The basin will discharge via a spillway which will be linked

either to the existing culvert under the road, a new upsized culvert under the road but in the

same location, or if the sediment basin is constructed in the alternate location, a new culvert

will be constructed and tied into the drainage channel on the eastern side of the gravel road.

Exact culvert requirements will be determined as a function of the detailed design WRD

footprint and basin.

The amount of stormwater runoff from the WRD is unlikely to be significantly greater than the

current discharge from the existing catchment. The amount discharged will depend on each

rainfall event. As discussed in the WRMP, the spillway, the embankment and the culvert will be

designed to accommodate the 1 in 50 year peak flow, approximately 740 L/s. It is however

highly unlikely that the 1 in 50 year event will occur during the short life of the sediment basin.

Just as the existing catchment sheds regularly runoff, which is concentrated by the road

culvert, day to day spills are likely from the basin but will be of a much smaller magnitude than

the 1 in 50 year flow. Discharge quantities will depend not only on rainfall events but by

saturation levels in the catchment, the surface area of the basin (evaporation losses), and

exfiltration (losses) of basin water through the basin floor or walls.

Comment - Page 16 of Supp states that at least three ponds will be constructed to capture and

treat mine water. Drawing H4-01 (Appendix 8-Maps and drawings) shows the presence of at

least four ponds; please clarify the nature and relationships of all ponds depicted in H4-01.

Response – The conceptual design of the water infrastructure as outlined in the WMP states

that the final design will likely comprise at least three basins in sequence. Drawing H4-01 has

been updated with labels, and shows an indicative layout of 3 interlinked sediment basins and

a retention basin, which allows for maximum flexibility in regards to water improvement and

process water retention. Section 3.2 and 3.3 of the WMP detail the conceptual design of the

sediment ponds for the purpose of sediment and coal dust control, while section 5.2.4 and



5.2.5 of the AMD Contingency Management Plan attached in Appendix 13 detail the

conceptual design of the passive and active treatment processes in the unlikely event of AMD

leachate requiring treatment.

Comment - Drawing H3-04 (water management schematic) should show how the package

treatment plant relates to/ integrates with site water management (given that this plant will

now discharge to water improvement ponds).

Response – Agreed, and this drawing has been updated to reflect this change.

Comment - Transport of interburden to Abrahams quarry is an uphill distance of about five kin

on FT roads. Supp should forecast likely number of heavy vehicle movements per day involved

in transfer of interburden to ex quarry site and whether road is suitable for this activity.

Response - The ‘worst case’ volume of interburden to be extracted during initial mine

development is calculated as 30,500 m2 as bulked up fill, the calculations for which are

discussed in an earlier response. This extraction and haulage will occur over a period of

approximately 6 months. The haulage will likely be undertaken by truck and trailers capable of

transporting up to 24m3 per load. This equates to 7 truck movements from the mine site to

Abraham’s quarry and back each day during this period.

The haulage will occur along Valley Rd, an unsealed Forestry Tasmania road. Forestry Tasmania

has indicated that 10,000 m3 of quarry material and 50,000 tonnes of logs are currently carted

along Valley Rd each year. This indicates that Valley Rd is currently in a suitable condition to

handle the proposed volume of truck movements.



4 Revised Commitments

Commitment 1 – Further geotechnical investigations will be completed before detailed

engineering of site infrastructure is undertaken.

Commitment 2 - Diesel usage will be minimised where possible by the selection of best-

practice plant and equipment for use during mining operations, and ensuring this equipment is

kept in optimal running order.

Commitment 3 - Coal dust will be minimised during extraction, storage and transport through

the raising of coal moisture levels.

Commitment 4 - Valley Rd will be sealed to a pavement width of 6.2m between the Esk Hwy

and the Project Site entrance, and appropriate road warning signage will be installed as

required by DIER and relevant Australian Standards.

Commitment 5 - Excess water discharge volume and quality will be managed via the Water

Management Plan to adhere to EPA conditions.

Commitment 6 – Further hydrogeological investigations will be undertaken in conjunction with

ongoing resource definition and operational drilling, to develop the groundwater flow model

beyond the first 3 years of operations.

Commitment 7 - The net discharge groundwater quality will be continually monitored, to

inform the water improvement process.

Commitment 8 - A suitable noise-mitigating design will be engineered for the projection of the

conveyor over the top of the hoppers.

Commitment 9 – Waste rock produced during initial mine development will be characterised

according to its potential to form AMD, and stored as per the Waste Rock Management Plan

and AMD Contingency Management Plan. Additional waste rock extracted during mining

operations will be stored underground.

Commitment 10 - All solid wastes will be removed and disposed of by suitably qualified waste

removal contractors.

Commitment 11 - Formalise agreement with Forestry Tasmania to preserve all forest that acts

to mitigate line of sight and noise disturbance to known WTE nests in proximity of the site



through a Forest Lease agreement.

Commitment 12 - A Special Values Management Plan for threatened fauna species will be

developed for the construction and operational phases of the project.

Commitment 13 - A Heritage Management Plan will be developed to manage removal of

European heritage items.

Commitment 14 – An Unanticipated Discovery Management Plan will be developed to manage

any Aboriginal site or relic discovery in accordance with the Aboriginal Relics Act 1975.

Commitment 15 - Site infrastructure will be coloured in tones similar to the surrounding

vegetation and natural features.

Commitment 16 - A site Safety and Environmental Management Plan will be developed for use

during mine construction and ongoing operation.

Commitment 17 – Tasmania Fire Service and Forestry Tasmania will be consulted during

development of the Fire Management Plan.

Commitment 18 - A Traffic Management Plan will be developed to guide haulage operations

on site and Valley Rd prior to the commencement of onsite construction activities.

Commitment 19 - Weed and disease mitigation measures as per NRM South field hygiene

guidelines and Interim Phytophthora cinnamomi Management Guidelines will be incorporated

into site SEMP.

Commitment 20 - Water quality will be monitored on a monthly basis at locations and for

parameters outlined in the Water Management Plan.

Commitment 21 - A Mine Closure Plan will be developed within 2 years of commencement of

mining operations.

Commitment 22 – Water quality at the waste rock dump’s settling pond will be monitored on a

monthly basis for parameters outlined in the Water Management Plan for a period of at least

the first 12 months.

Commitment 23 – The AMD management procedures and mitigation measures will be

implemented as outlined in the AMD Contingency Management Plan.



5 Appendices

Appendix 1 – Botanical Follow-up report

Appendix 2 – Geotechnical Assessment and follow-up letter

Appendix 3 – Wetlands and Waterways Code Response Letter

Appendix 4 – Letter from PCAB

Appendix 5 – Natural Values Report

Appendix 6 – Acid and Metalliferous Drainage Assessment

Appendix 7 – Stage 2 Hydrogeological Review

Appendix 8 – Plans and Drawings

Appendix 9 – Letter from Forestry Tasmania

Appendix 10 – Peer Review of Geotechnical Assessment

Appendix 11 – Water Management Plan

Appendix 12 – Waste Rock Management Plan

Appendix 13 – AMD Contingency Management Plan

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Figure 3

Job NumberRevision 0

32-16074

G:\32\16074\GIS\Maps\3216074_001_Rev0.mxd

Map Projection: Transverse MercatorHorizontal Datum: GDA 1994Grid: GDA 1994 MGA Zone 55

0 100 20050

Metres o© 2012. Whilst every care has been taken to prepare this map, GHD (and Google and DPIPWE) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason.

Date 16 Mar 2012

CBM Sustainable DesignFingal Tier Coal MineBotanical Survey

Vegetation Communities and Hollow Bearing Trees

Data source: CBM Design Solutions survey, Google satellite imagery 2010, DPIPWE Tasmaps road 2008 (digitised by GHD 2012), GHD vegetation survey 2012. Created by: jtoregan, updated by jpulford

2 Salamanca Square Hobart TAS 7000 Australia T 61 3 6210 0600 F 61 3 6210 0601 E [email protected] W www.ghd.com.au

Paper Size A4 LEGENDStudy AreaRoadContour

CreekProposed Mine Infrastructure

#* Hollow Bearing Tree / Stag

Dry Eucalypt Forest and WoodlandDAS E. amygdalina forest and woodland on sandstone (threatened)DAD E. amygdalina forest and woodland on dolerite

Scrub, heathland and coastal complexesSBR Broad-leaf scrub

SITE LOCATION

HOBART

STUDY SITE

Development Proposal and Environmental Management Plan … Coal Mining... · 2012-08-31 ·...

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