Bulga Coal Water Management Plan Declaration of accuracy INTRODUCTION Purpose Scope Objectives...

Transcription

1 EPBC APPROVAL 2012/6637 Table of Contents Bulga Coal Water Management... 1 Declaration of accuracy INTRODUCTION Purpose Scope Objectives PLANNING REQUIREMENTS Overview Development Consent Conditions Mining Leases Mining Lease (ML 1547) Mining Lease (ML 1494) Mining Lease (ML 1674) Mining Lease (CL 224) Exploration Licences Exploration Licences A450, A447, EL5461, and EL Licences Environmental Protection Licence Groundwater Licences Surface Water Licences EXISTING SITE OVERVIEW Introduction Hydrology Geology and Hydrogeology WATER MANAGEMENT PRINCIPLES General Water Management Classes, Design Objectives and Performance Criteria Current Operational Philosophy EXISTING WATER MANAGEMENT SYSTEM Clean Water Management Mine Water Management Underground Mine Water Management Open Cut Pit Water Management CHPP Water Management Controlled Discharges Discharges via Licenced Discharge Points Future Licenced Discharge Point FUTURE WATER MANAGEMENT DEVELOPMENTS General Year Year Version: 1.0 Page 1 of 72

2 7. SITE WATER BALANCE Model Overview Overall Site Water Balance Model Results Water Supply Reliability Controlled Releases Hunter River Extraction Water Efficiency Water Balance Monitoring Water Balance Model Review EROSION AND SEDIMENT CONTROL BCC Operations BOP Construction Phase SURFACE WATER MONITORING PROGRAM Baseline Data Surface Water Quality Mine Water Quality Streamflow Surface Water Impact Assessment Criteria Surface Water Monitoring Surface Water Quality Onsite Mine Water Quality Monitoring Stream Health and Channel Stability Private Dams GROUNDWATER MONITORING PROGRAM Groundwater Monitoring Network Baseline Data Groundwater Inflows into the Open Cut Groundwater Impact Assessment Criteria Groundwater Monitoring Groundwater inflows into the Open Cut Pit Seepage from water storages, emplacements and voids Regional and local aquifers Groundwater supply in privately owned bores Groundwater Dependent Ecosystems Wollombi Brook Baseflow Groundwater Model Review SURFACE AND GROUNDWATER RESPONSE PLAN Exceedance of Trigger Values Response Unforeseen Impacts DECOMMISSIONING STRATEGIES REPORTING REVIEW AUDITS AND INSPECTIONS Internal Audits External Audits Version: 1.0 Page 2 of 72

3 16. ACCOUNTABILITIES COMPLAINTS PROCEDURES TRAINING AND AWARENESS REFERENCES CONTROL AND REVISION HISTORY Document information Revisions Declaration of accuracy In making this declaration, I am aware that section 491 of the Environment Protection and Biodiversity Conservation Act 1999 (Cth) (EPBC Act) makes it an offence in certain circumstances to knowingly provide false or misleading information or documents to specified persons who are known to be performing a duty or carrying out a function under the EPBC Act or the Environment Protection and Biodiversity Conservation Regulations 2000 (Cth). The offence is punishable on conviction by imprisonment or a fine, or both. I am authorised to bind the approval holder to this declaration and that I have no knowledge of that authorisation being revoked at the time of making this declaration. Signed Ralph Northey Bulga Coal 22 February 2017 Version: 1.0 Page 3 of 72

4 1. INTRODUCTION The Bulga Coal Complex (BCC) is located approximately 12 kilometres (km) southwest of Singleton, and approximately 2 km from the townships of Broke and Bulga, in the Upper Hunter Valley of New South Wales (NSW). BCC comprises two coal mining operations, being the Bulga Open Cut (BOC) operations and the Bulga Underground Operations (BUO). The Bulga Open Cut incorporates the Bulga Coal Handling and Preparation t (CHPP) and the Bulga Underground incorporates the Blakefield South Mine and the approved but yet to commence Blakefield North Underground Mine. The CHPP and the rail loading facility are located in the north-east corner of the BCC and service both operations. The Bulga Optimisation Project (BOP) is a continuation of the existing open cut operations located largely within the existing BOC mining lease area. It involves accessing underlying coal seams not previously mined within the open cut pit, and extending the open cut pit towards the east. Underground operations are largely unaffected by the BOP. BCC is managed by Bulga Coal Management Pty Ltd on behalf of the Bulga Joint Venture. Bulga Coal Management Pty Ltd is owned by Oakbridge Pty Ltd, which also is the majority shareholder (87.5%) of the Bulga Joint Venture. Glencore, which acquired Xstrata in early 2013, is the majority shareholder of Oakbridge Pty Ltd. BCC currently operates pursuant to DA SSD-4960 (the BOC consent) and modified DA (the BUO consent). The BCC Water Management (WMP) pulls together the processes and responsibilities of all aspects of the site Integrated Water Management System (IWMS). This WMP has been compiled to satisfy the relevant requirements of the aforementioned consents as well as Condition 4 of the Australian Government Department of the Environment approval under section 130(1) and 133 of the Environment Protection and Biodiversity Conservation Act 1999 (EPBC approval 2012/6637). In accordance with Schedule 3, Condition 25(a) of DA SSD-4960 the WMP has been prepared by suitably qualified and experienced persons whose appointment has been approved by the Secretary. Furthermore the WMP has been prepared in consultation with the Department of ning & Environment (DP&E), NSW Office of Water (NOW) and the Office of Environment and Heritage (OEH). 1.1 Purpose The purpose of BCC WMP is to document the structured approach to managing water capture, supply, consumption, storage, disposal and hydrological interception for both BOC and BUO. In addition to this the purpose of the WMP is to: Guide the management of surface and groundwater resources throughout the construction and operational life of the mine; Address the relevant conditions of the Development Application consents such as: o o o documenting the water balance for the development; documenting baseline surface water and groundwater flow and quality information for watercourses potentially affected by the development; describing the water management system including design objectives and performance criteria; Version: 1.0 Page 4 of 72

5 o detailing the groundwater assessment criteria and trigger levels / performance indicators; o o o o o o documenting management actions and mitigation measures to minimise the impact of the development; outlining surface water and groundwater monitoring and reporting requirements; documenting the process of groundwater model validation and independent review; outlining a contingency plan to respond to unpredicted impacts and exceedances of assessment criteria; outlining the reporting and reviewing requirements; and detailing the accountabilities and responsibilities associated with implementation of the WMP; as well as Address legislative requirements and guidelines relevant to the WMP. 1.2 Scope The scope of the WMP includes all activities associated with the management of water at BCC (inclusive of the open cut and underground operations) with the exception of the potable water supply. The extent of this area is presented on Figure 1. The potable water supply is sourced from the Singleton Council Broke Village system and is not included in the scope of this WMP. The scope of the BCC WMP includes describing the existing IWMS for the BOC operation and BUO at the commencement of the approved BOP. It further describes the future changes and developments of the IWMS after one year and four years of continued operation of the BCC. 1.3 Objectives The objectives of the WMP are to: minimise the contamination of clean water runoff from catchment areas upstream of the operations by directing clean water around the disturbance footprint where possible; minimise the potential effects of erosion and its associated impacts as a result of mining operations changing flows or conditions downstream; prevent the discharge of pollutants from the disturbed area except where discharges are licenced, or where the discharge will not cause environmental harm such as water suitable for release from rehabilitated areas; maximise the reuse of mine water to meet on site water consumption requirements to reduce the need for water from the Hunter River; secure access to water for the operations during periods when there is insufficient water from the IWMS; and manage the disposal of excess water in line with relevant licence and Hunter River Salinity Trading Scheme (HRSTS) conditions when excess water volumes are stored on site beyond projected future requirements. Version: 1.0 Page 5 of 72

6 Figure 1 Locality Version: 1.0 Page 6 of 72

7 2. PLANNING REQUIREMENTS 2.1 Overview The BCC operations are regulated by a range of leases, licences and approvals. BCC currently operates under two NSW Development Consents (BUO DA and BOC DA SSD-4960) as well as Development Consent conditions provided by the Federal Australian Government Department of the Environment under section 130(1) and 133 of the Environment Protection and Biodiversity Conservation Act The requirements of these consents that are relevant to the WMP are outlined in Table 1 to Table 3, respectively. In addition to these Development Consents, BCC operates within the following leases, ML 1547, ML 1494, ML 1674, ML 1717 and Coal Lease (CL) 224. The requirements of these leases that are relevant to the WMP are outlined in Table 4 to Table 7. BCC are also able to undertake exploration activities in accordance with Exploration Licences and Authorisations. The requirements of these Exploration Licences and Authorisations relevant to the WMP are outlined in Table Development Consent Conditions Table 1 Relevant Water Management Conditions (DA ) Condition SCHEDULE 3 - ADMINISTRATIVE CONDITIONS Requirement 4A. Within 3 months of any modification to this consent, the Applicant shall review and if necessary revise all strategies/plans/programs required under this consent which are relevant to the modification, to the satisfaction of the Secretary. SCHEDULE 4 - SPECIFIC ENVIRONMENTAL CONDITIONS Section Addressed Section Pollution of Waters 9 - Discharge Limits Except as may be expressly provided by an Environment Protection Licence, the Applicant shall comply with section 120 of the Protection of the Environment Operations Act 1997 during the carrying out of the development. Except as may be expressly provided by an Environment Protection Licence or the Protection of the Environment Operations (Hunter River Salinity Trading Scheme) Regulation 2002, the Applicant shall: (a) not discharge more than 55 ML/day from the licensed discharge point/s at the development; and Section 2.41& Section 5.3 Version: 1.0 Page 7 of 72

8 Condition 10 - Site Water Balance 11- Flood Exclusion Levee 12- Flood Exclusion Levee 13 - Monitoring Requirement (b) ensure that the discharges from any licensed discharge points comply with the limits in Table 2: Table 2 Discharge limits Pollutant Units of measure 100 percentile concentration limit ph ph 6.5 ph 9.5 Non-filterable residue mg/litre NFR 120 Note: This condition does not authorise the pollution of waters by any other pollutants Each year, the Applicant shall: (a) review the site water balance for the development against the predictions in the EIS; (b) re-calculate the site water balance for the development; and (c) report the results of this review in the AR. These calculations must exclude the clean water system, including any sediment control structures, and any dams in the mine lease area which fall under the Maximum Harvestable Right Dam Capacity; include any dams that are licensable under Section 205 of the Water Act 1912, and water harvested from any non-harvestable rights dam on the mine lease area; address balances of inflows, licensed water extractions, and transfers of water from the site to other sites; include an accounting system for water budgets; and include a salt budget. The Applicant shall design, construct, maintain, and rehabilitate the Flood Exclusion Levee to the satisfaction of the Secretary. This levee shall: (a) remain stable under a 1 in a 100 year ARI flood event; and (b) not cause an increase in backwater stream heights in Wollombi Brook of greater than 20mm upstream of the confluence of the unnamed watercourse and Wollombi Brook under conditions up to and including a 1 in a 100 year ARI flood event. Within one month of completing the construction of the Flood Exclusion Levee, the Applicant shall submit an as-executed report, certified by a practising registered engineer, to the Secretary. The Applicant shall: (a) measure: the volume of water discharged from the site via the licensed discharge points; water use on the site; dam and water structure storage level for dams associated with the mine discharge system; water transfers across the site; and water transfers between the site and surrounding mines; Bulga Coal Section Addressed Section 7 Wollombi Brook Flood Exclusion Levee (BSM SD PLN 0068) Section 9.32 Version: 1.0 Page 8 of 72

9 Condition 14 - Site Water Management 15 - Site Water Management 16 - Site Water Management 17 - Site Water Management Requirement (b) monitor the quality of the surface water: discharged from the licensed discharge point/s at the development; and upstream and downstream of the development; (c) monitor flows in the Wollombi Brook; (d) monitor the volume and quality of water inflows to and from the underground workings; and (e) monitor regional ground water levels and quality in the alluvial, coal seam, and inter-burden aquifers during the development and at least 10 years after mining, and (f) periodically assess groundwater pressure response in the coal measures; in consultation with DECCW and NOW and to the satisfaction of the Secretary. Within 12 months of the date of this consent, the Applicant shall prepare or update the existing Site Water Management for the development in consultation with DECCW, and to the satisfaction of the Secretary. This plan must include: (a) the predicted site water balance; (b) a Surface Water Monitoring Program; (c) a Ground Water Monitoring Program; (d) a Surface and Ground Water Response ; and (e) a strategy for decommissioning water management structures on the site. The Surface Water Monitoring Program shall include: (a) detailed baseline data on surface water flows and quality in the Wollombi Brook and Loders Creek; (b) surface water impact assessment criteria; (c) a program to monitor surface water flows and quality in the Wollombi Brook and Loders Creek; and (d) a program to monitor the effectiveness of the Erosion and Sediment Control. The Ground Water Monitoring Program shall include: (a) detailed baseline data on ground water levels and quality, based on statistical analysis, to benchmark the pre-mining natural variation in groundwater levels and quality; (b) ground water impact assessment criteria; (c) a program to monitor the volume and quality of ground water seeping into the underground mine workings; and (d) a program to monitor regional ground water levels and quality in the alluvial and coal seam aquifers. The Surface and Ground Water Response shall include: (a) measures to mitigate any adverse impacts on existing water supply bores or wells in either the alluvial or coal measure aquifer systems; Bulga Coal Section Addressed Sections 9.13 and 9.31 Sections 9.13 and 9.31 Section 9.32 Section 10 Section 10.5 This Document Section 7 Section 9 Section 10 Section 11 Section 12 Section 9.1 Section 9.2 Section 9.3 Section 8 & 9.33 Section 10.1 & 10.2 Section 10.3 Section 10.4 Section 10.4 Section 11 and the Wollombi Brook and Monkey Place Creek Surface Version: 1.0 Page 9 of 72

10 Condition 18 - Flood Levee 19 - Erosion and Sediment Control 20 - Surface & Sub-surface Investigation & Monitoring Program Requirement (b) measures to remediate any connective cracking between the underground mine workings and any surface water stream channels, floodplain areas, or the alluvial aquifer; (c) measures to address a decrease in throughflow rates caused by the development within the Wollombi Brook/Monkey Place Creek alluvium adjacent to or downstream of the development within the mine lease boundary; and (d) the procedures that would be followed if any unforeseen impacts are detected during the development. Three months prior to the commencement of construction of the flood levee on the northern drainage line, the Applicant shall submit a Flood Exclusion Levee for the Secretary s approval. The shall include: (a) the detailed design and specifications of the levee, including any measures to allow waters to flow through the levee when required; (b) the measures that would be implemented to minimise soil erosion and the potential for the migration of sediments to downstream waters; (c) a construction program for the levee, describing how the work would be staged, and integrated with the proposed works in the Northern Drainage Line; and (d) a program to inspect and maintain the levee and associated revegetation works during the development. Three months prior to the commencement of construction works outside the Bulga Complex Water Management System or subsidence remediation, the Applicant shall submit an Erosion and Sediment Control for the Secretary s approval. The shall: (a) be consistent with the requirements of the Department of Housing s Managing Urban Stormwater: Soils and Construction manual; (b) identify activities that could cause soil erosion and generate sediment; (c) describe the location, function, and capacity of erosion and sediment control structures; and (d) describe the measures to minimise soil erosion and the potential for the migration of sediments to downstream waters. Note: The Erosion & Sediment Control should only relate to development that is scheduled to occur outside the mine s dirty water system. Given that this development is likely to be staged, the Department accepts that the Erosion & Sediment Control is likely to be prepared in stages to coincide with the relevant stages of the development. Within 12 months of the date of this consent, or prior to the commencement of longwall extraction in the approved panels, whichever occurs first, the Applicant shall develop and implement a surface and subsurface investigation and monitoring program to assess the likely fracturing of geological strata and hydraulic property changes above each longwall panel, to the satisfaction of the Director- General. This program shall: (a) assess the impact on groundwater resources and surface expression resulting from underground mining at varying depths; Bulga Coal Section Addressed water and groundwater Response (BSM SD PLN 0020) Wollombi Brook Flood Exclusion Levee (BSM SD PLN 0068) Section 8 Section 10 and the Wollombi Brook and Monkey Place Creek Surface and Groundwater Response (BSM SD PLN 0020) Version: 1.0 Page 10 of 72

11 Condition 21 - Final Void Management Requirement (b) compare the results from all longwall panels against premining baseline geological conditions, in order to assess the level of variability of fracture and changes in hydraulic properties between panels; and (c) be repeated for each coal seam as it is mined. At least 5 years prior to the completion of the development, the Applicant shall evaluate the potential long-term impacts of any final pit voids on groundwater resources, and develop an appropriate management plan to the satisfaction of the Secretary. Bulga Coal Section Addressed Section 12 Table 2 Relevant Water Management Conditions (DA SSD-4960) Condition Requirement SCHEDULE 3 ENVIRONMENTAL PERFORMANCE CONDITIONS 24 Water Supply The Applicant shall ensure that it has sufficient water for all stages of the development, and if necessary, adjust the scale of mining operations to match its available water supply. Section Addressed Section 7 25 Water Transfers 26 Water Pollution 27 Water Management Performance Measures Note: Under the Water Act 1912 and/or the Water Management Act 2000, the Applicant is required to obtain necessary water licences for the development. The Applicant may receive water from, and transfer water to, the Mt Thorley mine. Unless an EPL or the EPA authorises otherwise, the Applicant shall ensure all surface water discharges from the site comply with the discharge limits (both volume and quality) set for the development in any EPL; and relevant provisions of the POEO Act of Protection of the Environment Operations (Hunter River Salinity Trading Scheme) Regulation Note: for the avoidance of doubt, it is noted that the EPA will determine the cumulative allowable salinity discharges to the Hunter River Catchment, according to rules of the Hunter River Salinity Trading Scheme and the respective quantities of tradeable salinity credits held by participants in the scheme (including the Mount Thorley Mine and other nearby mining operations). The Applicant shall comply with the performance measures in Table 8 to the satisfaction of the SecretarySecretary. Section 3 Section 1.3 Section 5.3 Section 9 & Section 10 Section 4, Section 5, Section 6, Section 9, Section 10 & Section 11 Version: 1.0 Page 11 of 72

12 Condition Requirement Table 8: Water management performance measures Feature Performance Measure Water Minimise the use of clean water on site management Minimise the need for make-up water from external General supplies Minimise cumulative water impacts with the other Construction and operation of infrastructure Clean water diversion & storage infrastructure Sediment dams Mine water storages Overburden emplacements Chemical and hydrocarbon storage Aquatic and riparian ecosystem mines in the region Design, install and maintain erosion and sediment controls generally in accordance with the series Managing Urban Stormwater: Soils and Construction including Volume 1, Volume 2A Installation of Services and Volume 2C Unsealed Roads Design, install and maintain the infrastructure within 40 m of watercourses generally in accordance with the Guidelines for Controlled Activities on Waterfront Land (DPI 2007), or its latest version Design, install and maintain any creek crossings generally in accordance with the Policy and Guidelines for Fish Friendly Waterway Crossings (NSW Fisheries, 2003) and Why Do Fish Need To Cross The Road? Fish Passage Requirements for Waterway Crossings (NSW Fisheries 2003), or their latest versions Design, install and maintain the clean water system to capture and convey the 100 year ARI flood Maximise as far as reasonable and feasible the diversion of clean water around disturbed areas on site Design, install and maintain the dams generally in accordance with the series Managing Urban Stormwater: Soils and Construction Volume 1 and Volume 2E Mines and Quarries Design, install and maintain mine water storage infrastructure to ensure no unlicensed or uncontrolled discharge of mine water off-site Except for the Bayswater Pit tailings storage and final void, on-site storages (including tailings dams, mine infrastructure dams, groundwater storage and treatment dams) are suitably lined to comply with a permeability standard of <1 x 10-9 m/s, or a suitable alternative which has been agreed to by the Secretary Adequate freeboard within the pit void at all times to minimise the risk of discharge to surface waters Design, install and maintain emplacements to encapsulate and prevent migration of tailings, acid forming and potentially acid forming materials, and saline and sodic material Design, install and maintain emplacements to prevent and/or manage long term saline groundwater seepage Chemical and hydrocarbon products to be stored in bunded areas in accordance with the relevant Australian Standards Maintain or improve baseline channel stability Develop site-specific in-stream water quality objectives in accordance with ANZECC 2000 and Using the ANZECC Guidelines and Water Quality Objectives in NSW procedures (DECC 2006), or its latest version Bulga Coal Section Addressed Section 4, Section 5, Section 6, Section 9, Section 10 & Section 11 Version: 1.0 Page 12 of 72

13 Condition 25 Water Management Requirement The Applicant shall prepare and implement a Water Management for the development to the satisfaction of the SecretarySecretary. This plan must: (a) be prepared in consultation with the EPA, NOW and OEHDPI Water, by suitably qualified and experienced person/s whose appointment has been approved by the SecretarySecretary; (b) be submitted to the SecretarySecretary for approval within 12 months of the date of this consent; and (c) in addition to the standard requirements for management plans (see condition 3 of schedule 5), include a: (i) Site Water Balance that: includes details of: o sources and security of water supply, including contingency planning for future reporting periods; o water use and management on site, including details of water sharing between neighbouring mining operations; o any off-site water transfers and discharges; o reporting procedures, including the preparation of a site water balance for each calendar year; and investigates and implements all reasonable and feasible measures to minimise water use on site; (ii) Surface Water Management, that includes: detailed baseline data on surface water flows and quality in the watercourses that could potentially be affected by the development; a detailed description of the water management system on site, including the: o clean water diversion systems; o erosion and sediment controls (mine water system); and o mine water management systems including irrigation areas detailed plans, including design objectives and performance criteria, for: o design and management of final voids; o design and management for the emplacement of coal reject materials; o reinstatement of drainage lines on the rehabilitated areas of the site; and o control of any potential water pollution from the rehabilitated areas of the site; performance criteria for the following, including trigger levels for investigating any potentially adverse impacts associated with the development: o mine water management system; o surface water quality of Loders Creek and Wollombi Brook; and o channel stability, stream and riparian vegetation health of Loders Creek and Wollombi Brook; a program to monitor and report on: o the effectiveness of the mine water management system; and o surface water flows and quality, stream and riparian vegetation health in Loders Creek and Wollombi Brook potentially affected by the development; a plan to respond to any exceedances of the performance criteria, and mitigate and/or offset any adverse surface water impacts of the development; and Bulga Coal Section Addressed Section 1 - Section 7 Section 7.3 Section 9.1 Section 5 & Section 6 Section 4 Section 9 Section 9.3 Section 11 Version: 1.0 Page 13 of 72

14 Condition Requirement (iii) Groundwater Management, which includes: detailed baseline data on groundwater levels, yield and quality in the region, and privately-owned groundwater bores, that could be affected by the development; Bulga Coal Section Addressed Section 10.1 & 10.2 groundwater assessment criteria, including trigger levels for investigating any potentially adverse groundwater impacts; a program to monitor and report on: o groundwater inflows to the open cut pits; o the seepage/leachate from water storages, emplacements, backfilled voids, and final voids; o the impacts of the development on: - regional and local (including alluvial) aquifers; - groundwater supply of potentially affected landowners; and - groundwater dependent ecosystems and riparian vegetation; and o base flows to Wollombi Brook; a program to validate the groundwater model for the development, including an independent review of the model with every independent environmental audit, and compare the monitoring results with modelled predictions; and a plan to respond to any exceedances of the groundwater assessment criteria. Section 10.3 Section 10.4 Section 10.4 & Section 14 Section 11 SCHEDULE 5 ENVIRONMENTAL MANAGEMENT, REPORTING AND AUDITING 3 Management Requirements The Applicant shall ensure that the management plans required under this consent are prepared in accordance with any relevant guidelines, and include: (a) detailed baseline data; (b) a description of: the relevant statutory requirements (including any relevant approval, licence or lease conditions); any relevant limits or performance measures/criteria; the specific performance indicators that are proposed to be used to judge the performance of, or guide the implementation of, the development or any management measures; (c) a description of the measures that would be implemented to comply with the relevant statutory requirements, limits, or performance measures/criteria; (d) a program to monitor and report on the: impacts and environmental performance of the development; effectiveness of any management measures (see c above); (e) a contingency plan to manage any unpredicted impacts and their consequences; (f) a program to investigate and implement ways to improve the environmental performance of the development over time; Section 9.1 & Section 10.2 Section 2, Section 9.2 & Section 10.3 Section 11 Section 9.3, Section 10.4 & Section 15 Section 11 Section 14 Version: 1.0 Page 14 of 72

15 Condition Requirement Section Addressed (g) a protocol for managing and reporting any: Section 11, incidents; Section 13, complaints; Section 15 & non-compliances with statutory requirements; and Section 17 exceedances of the impact assessment criteria and/or performance criteria; and (h) a protocol for periodic review of the plan. Section 14 Table 3 Relevant Water Management Conditions from Section 130(1) and 133 of the Environment Protection and Biodiversity Conservation Act 1999 approval 2012/6637 Condition Condition 4 Requirement The approval holder must submit for the Minister s approval a Water Management (WMP) which provides for the avoidance, mitigation and offsetting of residual impacts to water resources. The WMP must include: a. management actions, mitigation measures and practices designed to limit impacts of the proposal on surface and ground water resources; b. surface and groundwater monitoring programs to monitor the success of the management actions in the WMP and define measurable targets of management actions, performance indicators, and an adaptive management framework for the duration of the action s impact on water resources. Management actions, mitigation measures and practices prescribed by the plan must be clear, measurable, auditable and time bound; c. clear objectives and performance indicators, as well as corrective actions for circumstances where a management action, mitigation measure or practice fails to meet its prescribed objective or performance indicator. The WMP must be submitted within 3 months of commencement of the action. The approved WMP must be implemented. The approved WMP must be published on the approval holder s website within one month of approval of the WMP and remain published on this website for the duration of the action. Section Addressed This Document Section 9 & Section 10 Section 11 - Version: 1.0 Page 15 of 72

16 2.3 Mining Leases 2.31 Mining Lease (ML 1547) Table 4 Relevant Water Management Conditions (ML 1547) Condition Requirement MANAGEMENT AND REHABILITATION OF LANDS (GENERAL) 25 The lease holder shall provide and maintain to the satisfaction of the minister efficient means to prevent contamination, pollution, erosion or siltation of any river, stream, creek, tributary, lake, dam, reservoir, watercourse or catchment area or any undue interference to fish or their environment and shall observe any instruction given by the minister with a view of preventing or minimising the contamination, pollution, erosion or siltation of any river, stream, creek, tributary, lake, dam, reservoir, watercourse or catchment area or any undue interference to fish or their environment Section Addressed Section 4, Section 5, Section 6 & Section The lease holder shall conduct operations in such a manner as not to cause or aggravate soil erosion and the lease holder shall observe and perform any instructions given or which may be given by the Minister with a view of preventing soil erosion. (a) Operations shall be carried out in such a way as not to cause any pollution to the Hunter River Catchment Area. (b) If the lease holder is using or about to use any process which in the opinion of the minister is likely to cause the contamination of the waters of the said catchment area the lease holder shall refrain from using or cease using as the case may require such process within twenty four (24) hours of the receipt by the lease holder to do so. Section 4, Section 5, Section 6 & Section 8 Section 4, Section 5, Section 6 & Section 8 (c) The lease holder shall comply with any regulations now or hereafter to be in force for the protection of the said catchment area Mining Lease (ML 1494) Table 5 Relevant Water Management Conditions (ML 1494) Condition Requirement Section Addressed MANAGEMENT AND REHABILITATION OF LANDS (GENERAL) 18 - Prevention of soil erosion and pollution Operations must be planned and carried out in a manner that does not cause or aggravate air pollution, water pollution (including sedimentation) or soil contamination. For the purpose of this condition, water shall be taken to include any watercourse, water body or ground waters. The licence holder must observe and perform any instructions given by the Department in this regard. Section 8, Section 9 & Section 10 Version: 1.0 Page 16 of 72

17 2.33 Mining Lease (ML 1674) Table 6 Relevant Water Management Conditions (ML 1674) Condition Requirement Section Addressed 12 Prevention of soil erosion and pollution Prospecting operations must be carried out in a manner that does not cause or aggravate, air pollution, water(including groundwater) pollution, soil contamination or erosion unless otherwise authorised by a relevant approval, and in accordance with an accepted mining operations. Section 8, Section 9 & Section 10 Version: 1.0 Page 17 of 72

18 2.34 Mining Lease (CL 224) Table 7 Relevant Water Management Conditions (CL 224) Condition Requirement Section Addressed 4 g) a) The Mining operations plan must present a schedule of proposed mine development for a period of up to 7 years and contain diagrams and documentation which identify: g) water management systems (including erosion and sediment controls) The lease holder shall provide and maintain to the satisfaction of the Minister efficient means to prevent contamination, pollution, erosion or siltation of any river, stream, creek, tributary, lake, dam, reservoir, watercourse or catchment area or any undue interference to fish or their environment and shall observe any instruction given or which may be given by the Minister with a view to preventing or minimising the contamination, pollution, erosion or siltation of any river, stream, creek, tributary, lake, dam, reservoir, watercourse or catchment area or any undue interference to fish or their environment. Operations shall be carried out in such a way as to not cause any pollution of the Hunter Catchment Area Bulga MOP Section 4, Section 5, Section 6 & Section 8 Section 4, Section 5, Section 6 & Section Exploration Licences 2.41 Exploration Licences A450, A447, EL5461, and EL5277 Table 8 Relevant Water Management Conditions (A450, A447, EL5461 and EL5277) Condition Requirement Section Addressed 17 Streams and Watercourses The licence holder must not interfere with the flow of water in any stream or watercourse without the prior written approval of the Department, and subject to any conditions that may be stipulated. This Document and the Bulga Coal ESCP (BUL SD PLN 0023) Version: 1.0 Page 18 of 72

19 Condition 18 Erosion and Sediment Controls Requirement (a) All operations must be planned and carried out in a manner that minimises erosion and controls sediment movement. The licence holder must observe and perform any instructions given by the Department in this regard. (b) For operations requiring approval under Condition 2 the licence holder must document in any Reviews of Environmental Factors required a plan setting out the proposed methods for minimising erosion and controlling sediment movement. (c) The procedures undertaken to minimise erosion and control sediment movement must be included in reports prepared in accordance with Condition 28(a). Bulga Coal Section Addressed This Document and the Bulga Coal ESCP (BUL SD PLN 0023) 2.5 Licences 2.51 Environmental Protection Licence BCC operates under a single EPL (EPL 563) which is renewed annually on 29 July. EPL 563 contains two Licence Discharge Points (LDP's): LDP3 (Swan Lake) and LDP4 (CHPP Surge Dam), and stipulates a maximum discharge volume of 55 ML per day and 130 ML per day respectively Refer to Figure 2 for the LDP dams in the existing Integrated Water Management System and Figure 3 for the physical location of LDPs. Water quality parameters for both LDPs are outlined below in Table 9. Table 9 Concentration Limits for EPL 563 Pollution Units of Measure 100 percentile Concentration limit ph ph Total suspended Solids (TSS) Milligrams per litre Groundwater Licences BCC currently holds groundwater licences as outlined below in Table 10: 2.53 Surface Water Licences BCC has access to 876 ML of Hunter River allocation via the Singleton Council operated Mt Thorley water supply scheme. This supply is predominantly used by the underground operations for dust suppression on underground equipment. BCC also owns a number of rural properties which have Wollombi Brook water allocation licences but these have no bearing on the mining operations. Table 10 Water Licences Groundwater Licence 20BL BL BL Details Monitoring (mining bore): GW1 GW10. Total of 16 bores for monitoring purposes. Monitoring: P1 P3, P4A, P4B, P5 P8 and V3. Licence for total of 9 bores for monitoring purposes. Monitoring: Bore ACARP Project. Version: 1.0 Page 19 of 72

20 Groundwater Licence 20BL Monitoring: Bore ACARP Project. Details 20BL Monitoring: V1, V2, F1 and F2. 20BL BL BL BL BL BL BL BL Dewatering (mining): Beltana Longwall 1 Borehole. Volume licence limit 500ML. Mining: Underground workings. Volume licence limit 365ML. Dewatering (mining): Beltana MG4. Volume licence limit 500ML. Dewatering (mining): South Bulga MGE1. Volume licence limit 500ML. Monitoring: WBR180 and WBR181. Monitoring: WBR182 and WBR183. Dewatering (mining): South Bulga MGE4. Volume licence limit 500ML. Monitoring: SBD194, SBD BL Monitoring Bore - 61// BL Monitoring Bore - 34// BL Monitoring Bore - 33// BL Monitoring Bore - 23// BL Monitoring Bore - 24// BL Monitoring Bore - 25// BL Monitoring Bore - 22// BL Monitoring Bore - 11// Surface water Licence Details 20BL Stock and Domestic - 7// BL Domestic - 13// BL Test Bore - 7// BL Stock and Domestic - 31// BL Domestic and Farming - 5// CA CA CA CA CA CA CA CA CA CA CA Irrigation: Ex (Hunter River Frontage) License volume limit 282 units Irrigation: Ex Feeney Property. Licence volume limit 290 units Irrigation: Ex Fernance Property. License volume limit 188 units Irrigation: Halkin Estate. Volume license limit 365 units Irrigation: Ex Smith-Leigh Property. Volume license limit 150 units Irrigation: Ex McClellan Property. Volume license limit 96 units Irrigation ex Foate Property. Volume license limit 21ML Irrigation: Ex Fordwich Hill. Volume license limit 66 units Irrigation: Ex Fordwich Hill. Volume license limit 9 units Irrigation: Ex Johnston Property. Volume license limit 125 units Irrigation Ex Larking Property. Volume license limit 50 units Version: 1.0 Page 20 of 72

21 Groundwater Licence 20CA CA Details Irrigation: Ex Smith-Leigh Property. Volume license limit 22 units Irrigation: Ex Fernance Property. License volume limit 80 units Version: 1.0 Page 21 of 72

22 Figure 2 Existing Integrated Water Management System Version: 1.0 Page 22 of 72

23 3. EXISTING SITE OVERVIEW 3.1 Introduction Water management at BCC has evolved to manage groundwater, surface runoff and mine water from the open cut and underground mining areas and decant from the CHPP tailings pit. The majority of the water onsite is extracted from underground or collected from surface runoff generated on mining disturbed areas. This water is preferentially recycled on site for use in the CHPP, for mine dust suppression and to maintain the statutory volumes of water required for operational purposes. Water at BCC is managed through the Integrated Water Management System (IWMS). The IWMS enables water to be reused onsite as required. Typically water is sourced from tailings decant, groundwater from the underground mine dewatering or from water that accumulates in other mine storages including open cut sumps. These sumps collect runoff from the approximate 2300 ha catchment area of the site. The IWMS allows the pumping of water around the site typically from its source to one of the three main storages on site, the Vaux Pit, the Bayswater Pit and the CHPP Surge dam. This system also enables the regulation of water supplied to site sourced from the Hunter River, and discharges via the LDP s and HRSTS. A schematic of the existing IWMS is shown in Figure 2. The existing water management system will need to be extended and modified as part of continued BOC operations. Changes to the water management system include the construction of new channels, dams, interconnecting pipelines and pump stations to capture and transfer water, primarily from the new Noise and Visual Bund, and the new Eastern Emplacement Area. Typically water is consumed at BCC through mine dust suppression (Open Cut and Underground) and coal washing in the CHPP. Water is also lost through evaporation or discharged via the LDP's. The CHPP is by far the largest consumer of water on site and average net use of approximately 2500 ML/yr, Open Cut dust suppression consumes approximately 1400 ML/yr while the underground mining operations require approximately 500 ML/yr. Supply of potable water to offices, workshops, bathhouses and underground workings is drawn from Singleton Council Broke Village water supply. Generally water intercepted by the mining operations meets the site raw water supply requirement, however in times of deficit or when required supplementary water is sourced from the Hunter River. Supplementary water, when sourced from the Hunter River, is transferred and stored in the 60 ML Dam through the Mount Thorley Water Supply Scheme, of which BCC is a member. Alternatively, in times of surplus, water can be released to the Hunter Hiver through the LDPs and in accordance with the EPL and HRSTS. BCC holds 867 ML/yr of Hunter River High Security Entitlements (HSE). The 60 ML Dam can be used to supply, as required, the CHPP, truck fill points or the underground operations. Wastewater from administration offices, workshops and bathhouses is collected and treated on site in one of two aerated sewage treatment plants (STPs). Treated wastewater is then returned to the IWMS for reuse. An overview of the existing IWMS is provided in Section 5 along with a description of the proposed changes to the IWMS as part of continued BOC operations and BUO in Section 6. Version: 1.0 Page 23 of 72

24 Figure 3 Existing and Proposed LDPs, Surface Water and Ground Water Monitoring Locations Version: 1.0 Page 24 of 72

25 / Bulga Coal 3.2 Hydrology The BCC surface water catchment flows either to: Loders Creek which drains northwards joining the Hunter River approximately seven kilometres upstream of Singleton. Loders Creek originally flowed through the mine, but is now diverted to the east of the open cut. the Northern and Southern drainage lines which drain to the west and southwest to Wollombi Brook. Nine Mile Creek flows immediately west of the CHPP and east of the workshop, administration and run-of-mine (ROM) stockpile areas and drains northwards to Loders Creek. Figure 1 shows the mine layout in relation to regional roads and aforementioned watercourses. 3.3 Geology and Hydrogeology BCC is geologically located within the Hunter Coalfield, northern part of the Sydney Basin. The area is underlain by Late Permian age strata- the Whittingham Coal Measures, which are directly overlain by the Wollombi Coal Measures Group. The late Permian sequence is characterised by a series of sandstone, siltstone, conglomerate and coal formations. The Late Permian strata outcrops across the site, but is overlain by more recent Quaternary alluvial deposits along watercourses - Wollombi Brook, Monkey Place Creek and Loders Creek. Detailed geology is provided in MER (2013). Three hydrostratigraphic units are identified within the Project area: Alluvial aquifer associated with Wollombi Brook, Monkey Creek Place and Loders Creek; Weathered and fractured shallow sandstone and coal strata, regolith and colluvium; and Fractured rock aquifer associated with Whittingham and Wollombi Coal measures. The alluvium typically has higher permeability and therefore yield. Private bores installed in this aquifer are used for stock and domestic and irrigation purpose. Weathered unit exhibits relatively low permeability and provides the transition zone. Fractured rock aquifer has generally poor quality water, has low permeability, hence it is not used as water supply. Page 25 of 72

26 4. WATER MANAGEMENT PRINCIPLES 4.1 General The following general water management principles are applied at BCC where possible: Minimise the use of clean water on site; Minimise the need for make-up water from external supplies; and Minimise cumulative water impacts with the other mines in the region. 4.2 Water Management Classes, Design Objectives and Performance Criteria Under Section 120 of the Protection of the Environment Operations Act 1997 (POEO Act) it is an offence to pollute waters or cause harm unless licenced to do so. Inherent in the concept of not causing harm is the need to manage the risk of spilling from water management dams or related infrastructure, and an understanding of the background qualities in the various creeks. For management purposes, three classes of water have been identified at Bulga Coal, typically dependent upon the source of the runoff. Table 11 lists the classes of water on site, describes their source, the target design objectives / performance criteria and the way they are managed. A detailed description of the management classes is provided in the Erosion and Sediment Control (ESCP) (BUL SD PLN 0023). Table 11 Water Management Classes, Design Objectives & Performance Criteria Surface Water Classification Description and Source(s) of runoff Target Design Objective / Performance Criteria Treatment Mine Water Water exposed to coal or used in coal processing. Sources of runoff may include: Haul roads Open cut mine pits Coal handling and stockpile areas Mine infrastructure areas (e.g. workshops, etc.) active overburden emplacement areas, This water quality is typically at a higher level of salinity in the range of 5000 μs/cm to 8500 μs/cm. Generally water at BCC is typically neutral to slightly alkaline with low metal concentrations. Water from MIAs (particularly workshops) has the potential to be contaminated with oils & hydrocarbons. New mine water infrastructure will be designed, installed and maintained to contain events up to and including the 100 year ARI, 24 hour storm event to mitigate the risk of uncontrolled discharge of mine water off-site. Generally any new onsite mine water storages will be suitably lined to a permeability of <1 x 10-9 m/s Contained within the mine water management system. Potential for controlled release from Swan Lake and the Surge Dam under the HRSTS and EPL conditions. Water from MIAs (sometimes contaminated with hydrocarbons) receive additional treatment by oil and water separators Page 26 of 72

27 Surface Water Classification Description and Source(s) of runoff Target Design Objective / Performance Criteria Treatment Dirty Water Runoff from disturbed areas (during both construction and operation). Sources of runoff include: rehabilitated overburden emplacement areas, general disturbed areas (e.g. construction areas, pre-stripped areas, etc.) These areas have the potential for moderately elevated salinity and elevated TSS. Diversion / storage infrastructure designed, installed and maintained in line with the Blue Book (Managing Urban Stormwater: Soils and Construction Volumes 1 and 2) and BCC ESCP (BUL SD PLN 0023). #1 #2 Directed to appropriately sized (Blue Book) dirty water sediment dams which are actively maintained and kept in a drawn down state. Refer to ESCP for further details regarding management of dams Clean Water Runoff from areas that are undisturbed as well as rehabilitated areas where vegetation is established. Diversion infrastructure designed, installed and maintained to convey a 100 year ARI storm event Maximised as far as reasonably practical and diverted around disturbance areas and allowed to flow into existing drainage lines off site #1 Any works within 40m of watercourses will generally be undertaken in accordance with the relevant Regulators Guidelines, Policies, etc. #2 Overburden emplacements are generally designed, installed and maintained to encapsulate and prevent migration of tailings, acid forming and potentially acid forming materials, and saline and sodic material as well as long term saline groundwater seepage. Dirty water is generated around site in general disturbance areas, construction areas, prestripped areas, gas drainage works and also on shaped soil overburden dumps. The management of dirty water is described in more detail within the ESCP. The design and management objectives for final voids are discussed in Section Current Operational Philosophy The current operating philosophy of the Integrated Water Management System is to: Retain approximately 1 year of water demand on site (2000 ML) in the CHPP Surge Dam; Maintain the Bayswater and Vaux pits at a low levels to provide short term mine dewatering storage; Maintain the Truck-fill dams, Fill Point 1 (FP1) and Dam 13 full; Discharge to the HRSTS when site storage exceeds 3000 ML; Selectively store better quality water in Swan Lake to ensure water that meets the EPL's requirements is available for discharge from the HRSTS when an opportunity to discharge is likely; Maintain the tailings emplacement facilities effectively decanted; Supplement raw water storage from the Hunter River when available on-site storage drops below 1500 ML; and Cease abstraction from the Hunter River when there is 2000 ML of available water stored on-site. Page 27 of 72

28 5. EXISTING WATER MANAGEMENT SYSTEM The existing IWMS incorporates water management from both the underground mine water management system and the open cut pit water management system. Both systems discharge to Dam 13 (amongst others) and can supply both the CHPP and active mining operations. The location of key dams and water handling infrastructure of the existing water management system are shown in Figure Clean Water Management There are three key clean water catchment areas upstream of mining that are currently managed as follows: The Nine Mile Catchment (SE of mining operations) drains an area of approximately 488 hectares. Nine Mile Ck flows in a Northerly direction between the mining operation and the CHPP and ultimately coalesces with Loders Ck. Upslope of the CHPP Surge Dam a catchment of approximately 145 hectares is located upstream of the CHPP Surge Dam, with an additional approximately 7 hectares upstream of the coal stockpile areas on the northern side of the CHPP area. The clean runoff upslope at the northern end of the CHPP Surge Dam is collected and pumped to an unnamed tributary of Nine Mile Creek. The clean runoff upslope of the southern end of the CHPP Surge Dam gravitates via a pipeline and constructed drain back to the same un-named tributary of Nine Mile Creek. Drainage over underground mining areas both the Northern Drainage Line and the Southern Drainage Line are undermined by longwall mining on the western side of the open cut pit. BCC undertakes regular work on these drainage lines to minimise the loss of clean runoff due to subsidence induced cracking and ponding and limit ingress as part of the BUO (managed in accordance with the underground consent DA ). Undermining will continue under the Northern Drainage Line and the Southern Drainage Line for the remainder of the Life of Mine (LOM), and this activity is not affected by the continued BOC operations. 5.2 Mine Water Management The mine water management system includes the collection, management, and distribution of water pumped from the underground workings and open cut, runoff and seepage from overburden emplacement areas, and management of water affected by coal handling and processing activities. The mine water management system comprises various dams, including water storage dams, pollution control and sediment dams, and the associated pumps and pipelines. Table 12 indicates the dams and storage areas currently part of the mine water management system together with their approximate design capacity and function. Page 28 of 72

29 Figure 4 Existing Water Management System Page 29 of 72

30 Table 12 Key Dams in the Mine Water Management System Dam Name Capacity (ML) Dams for Underground Water Supply Function Beltana Stat Dam 10 Fire water storage for underground; also feeds equipment. Minimum of 0.2 ML to be kept in the dam for fire water. Blakefield South Stat Dam 11 Fire water storage for underground; also feeds equipment. Minimum of 0.2 ML to be kept in the dam for fire water. Surface Dams FP 1 (Fill Point 1 Storage Dam) FP 2 (Fill Point 2 Storage Dam) (Dam 9) Dam 3 (Swan Lake) 42 Water pumped here from open cut pit, as well as Dam 13, CHPP Surge Dam and Swan Lake. Used as extraction point for dust suppression. 70 Collects runoff from rehabilitated area and also water pumped from haul road sumps. Used as extraction point for dust suppression. 263 Licenced discharge point. Balancing dam between supply to CHPP and Stat Dams. 60 ML Dam 64 Storage for Hunter River water. CHPP Surge Dam 2,990 Licenced discharge point. Capacity = 3100 ML minus 147 ML flood buffer storage. Surface Dams at the CHPP Area Dams C1, C2, C11, C12 Dams C4, C7, C9, C10, X and Y and Billabong 26 Mine water dams at CHPP area, east of Nine Mile Creek. 23 Dirty water dams at CHPP area, east of Nine Mile Creek. Dam C3 21 Main downstream mine water dam at CHPP area, east of Nine Mile Creek. Old Mining Voids Vaux Pit 1,480 Mine water storage and management. Bayswater Pit 1,090 Mine water storage and management. Whybrow Void 720 Collects runoff from temporary rehabilitation areas and unshaped overburden dumps Tailings dams Deep Pit 0 Used for tailings disposal. Dams constructed in Overburden Dam Mine water transfer dam between the open cut, CHPP and underground operations. Supply point for dust suppression. Underground Storage Reserve storage underground 1,000 Reserve storage in the Whybrow goaf. Note: Generally, the capacities given in Table 11 have been sourced from the Bulga Optimisation Project, Environmental Impact Statement, Volume 5, Surface Water Assessment. Page 30 of 72

31 5.21 Underground Mine Water Management Bulga Coal Water accumulates underground through a combination of groundwater inflows, together with water originating from the supply of water from surface to underground mining equipment. All surplus water drains to a number of underground water collection sumps, each equipped with pumps and associated pipelines that run from the underground to the surface. Water is then pumped to surface discharging either into a channel that flows to Dam 13 or directly to Dam 13. From Dam 13, water can be distributed for utilisation in the CHPP, for dust suppression, or stored for release in terms of the HRSTS. A new system of booster pumps has been installed to enable all of the water from underground to be pumped directly to the Bayswater Pit and other storage facilities. The new system reduces the need for Dam 13, which is due to be mined through as part of the continued BOC operations. As indicated, water is also required by the underground mining operations, as well as for dust suppression and fire protection. Water is supplied to the underground via the Blakefield South Stat Dam. The underground mine water management is largely unaffected by the continued BOC operations, although the water management for the underground mining operations are part of the IWMS. t and equipment maintenance for the BUO occurs at the workshop near the entry to the underground mine. Wastewater is collected in a sump and is fed through an oil/water separator which is serviced weekly. Surface water sampling around the BCC includes analysis for hydrocarbons with all sites averaging below detection limits. Audits of hydrocarbon facilities are conducted periodically Open Cut Pit Water Management The BOC is dewatered from various points, located in the northern, central and southern areas of the pit. Water is pumped primarily towards the east (Swan Lake) or the south (Dam 13), from where water can be pumped to the CHPP area via the Bayswater Pit or used for dust suppression. Fill Point 1 Storage Dam is also used to supply water to mine carts for dust suppression on haul roads. On the eastern side of the mining area, a series of dams collect runoff from the overburden. Ongoing monitoring of the water quality is undertaken at the sediment dams, and downstream of the overburden dumps CHPP Water Management The CHPP is located on either side of an un-named tributary of Nine Mile Creek. Dam C3 is the most downstream dam in a series of dams which captures runoff from the CHPP, ROM Pad and workshop areas. The surface water management system in this area is designed to ensure runoff from these areas does not flow to Nine Mile Creek which runs between the CHPP and workshop areas. Oil/water separators have been installed to capture and treat runoff from workshop and maintenance areas before reaching the water management dams. Dam C3 is equipped with pumps which enable pumping of water to the clarified water tank in the CHPP or Surge Dam. The CHPP is currently supplied with process water from the Bayswater Pit, although it is proposed to make the CHPP Surge Dam the main supply to the plant (refer to Section 6). The CHPP produces a fine rejects or tailings stream. Conventional gravity thickeners with flocculant addition are used at the CHPP to thicken the tailings prior to pumping to the Deep Pit. Decant from the tailings dams is reticulated to the Bayswater Pit. Page 31 of 72

32 5.3 Controlled Discharges 5.31 Discharges via Licenced Discharge Points There are currently two EPL licenced discharge (to waters) points as summarised in Table 13 and shown on Figure 3. Table 13 Current Licenced Discharge Points (LDPs) EPA Identification No. Location Limit 2 Dam 3 (Swan Lake - LDP3) 55ML/day 4 CHPP Surge Dam 130ML/day The HRSTS allows controlled discharges via LDPs based on volume and electrical conductivity during high or flood flows in the river. The scheme has a target salinity (EC) level of 900µS/cm for the lower sector of the HRSTS (between Glennies Creek and Singleton). EPL 563 prescribes the conditions in terms of water quality for releases as part of the HRSTS refer to Section The EC of the water is not specified in the EPL, but the EC is used by BCC to compute the volume of salt that can be discharged. EC remains a key component in the HRSTS discharge protocol. The Swan Lake LDP is fitted with calibrated volume and electrical conductivity telemetry, which can be interrogated remotely by BCC and the NSW Office of Environment and Heritage (OEH). The CHPP Surge Dam LDP is also fitted with calibrated volume and electrical conductivity telemetry, which can be interrogated remotely by BCC and the NSW Office of Environment and Heritage (OEH). All controlled discharges via LDPs are undertaken in accordance with the HRSTS discharge protocol Future Licenced Discharge Point Due to the progression of mining at BOC, there will be changes to the HRSTS release points and peak discharge volumes. BCC will apply to modify EPL No. 563 to allow discharge from the proposed Northern Dam once it has been constructed. The proposed future licenced discharge location is located on the Loders Creek system (refer to Figure 3). Until such times as discharge from the Northern Dam is approved, BCC will continue to discharge mine water from Swan Lake (maximum of 55ML/day) and the CHPP Surge Dam (maximum of 130ML/day) in accordance with the HRSTS. The combined discharges from Swan Lake, the CHPP Surge Dam and MTO (approved maximum discharge of 185ML/day) should not exceed 3.5 m 3 /s (i.e. approximately 300 ML per day) into Loders Creek upstream of the confluence with the un-named tributary on which the Northern Dam is located. Once approved, discharges from the Northern Dam will be managed to ensure that the combined discharges from the CHPP Surge Dam, Northern Dam and MTO do not exceed 9.6 m 3 /s (i.e. approximately 800 ML per day). At these proposed discharge rates, the impact on the un-named tributary and Loders Creek are not predicted to be significant. Page 32 of 72

33 6. FUTURE WATER MANAGEMENT DEVELOPMENTS 6.1 General The future changes to the BCC IWMS revolve around the implementation of the BOP. The BOP is a long term project and the key activities to be undertaken during the period of this WMP (Years 1-4) include: Mining within all pit areas; Construction of the new components of the water management system; Development of the external face of the Noise and Visual Bund with progressive shaping and rehabilitation; Commencement of the Eastern Emplacement Area; Construction of Broke Road realignment, internal access roads to infrastructure areas and construction of haul road bridges over Broke Road; Realignment of 330 kv transmission lines; and CHPP and open cut MIA upgrade works. As the WMP is reviewed and updated additional future activities will be included and described. Various components of the existing BCC IWMS will change as a result of continued BOC operations, including: the open cut dewatering system, which will pump from different locations and at lower elevations than is currently the case, requiring additional dewatering equipment, including measurement devices, and the use of booster pumps; the construction of the Northern Dam (2000 ML storage); and the construction of additional water management infrastructure to manage runoff and seepage from disturbance areas including the Noise and Visual Bund and Eastern Emplacement Area until rehabilitation is established, and other drainage infrastructure such as diversion drains around mining related infrastructure. In addition to the changes required as part of the continued BOC operations, BCC modified the existing BOC approval in 2014 to include a new sediment dam (Ramp 22 Dam) on the boundary with Mount Thorley Mine to capture surface water run-off from the common boundary emplacement area. The proposed dam will have a total capacity of approximately 88ML and will remove or reduce the capacity requirements for nearby existing Dam S5 and S6 as well as other sediment dams which manage run-off from the Mount Thorley side of the common boundary. The new dam will form part of the BCC IWMS until the sub-lease it is located in is transferred back to Mt Thorley operations. Changes to the IWMS are primarily driven by an increased disturbance area and landform changes associated with the continued BOC operations. While changes are proposed to the IWMS, the key functions of the IWMS remain as set out in Section 4.3. A summary of the proposed changes to the water management system is provided in the sections below. It is important to note that the timeframes given in the sections below are approximate only, and will be determined by construction and mining schedules. Furthermore, the schedule used indicates only which components of the IWMS are required for a particular stage of the mine, and does not preclude the construction of some components earlier. Page 33 of 72

34 6.2 Year 1 Pit dewatering during the initial phases will be largely unchanged, with water continuing to be pumped to the Bayswater Pit, Vaux Pit or the CHPP Surge Dam. It is proposed that the area of the Bayswater Pit may be mined through between Year 1 and Year 4. Should this occur, the Bayswater Pit may be dewatered in preparation for mining and all water redirected to other dams. The CHPP Surge Dam will remain the primary water storage facility. Construction of the Northern Dam will commence to provide storage volume to replace that lost by the eventual mining through of FP1 Dam, FP2 Dam, Vaux Pit and Swan Lake. Swan Lake will remain as a discharge point for the HRSTS until decommissioned. With the proposed construction of Dam S6 downstream of Swan Lake and FP2 Dam, it will no longer be possible to gravity feed water from Swan Lake to Loders Creek. Once Dam S6 is constructed, the HRSTS discharges are proposed to be undertaken from the CHPP Surge Dam and the Northern Dam (once constructed). The Vaux Pit and Bayswater Pit will continue to be used as reserve water storage facilities until such time as the Bayswater Pit is mined through. Key aspects of the additional surface water management system infrastructure to be constructed during Year 1 are summarised in Table 14 and shown on Figure 5. Table 14 Additional Surface Water Management Infrastructure for Year 1 Aspect Indicative Description New Clean Water Management Facilities New Mine Water Management Facilities Tailings Management Clean water upstream of the extension to the Bayswater Pit will initially be directed into the Bayswater Pit until construction of the Broke Road realignment is finished and the catchment is clean, at which point it will be diverted back into Nine Mile Creek. Clean water will also be diverted on the southern side of BOC close to the proposed Broke Road realignment. New dams and channels constructed to the southwest and north west to manage runoff from the Noise and Visual Bund. Dam S6 will be constructed in the north-eastern corner of the site to assist with flows off the common drainage line with Mt Thorley and areas where overburden from the East Pit Area will be emplaced. Construction will commence for the Northern Dam. Deep Pit will be used for tailings disposal. Capping of the Old Tailings Dam has commenced as part of the development of the Noise and Visual Bund. Page 34 of 72

35 Figure 5 BCC Year 1 Water Management System Page 35 of 72

36 6.3 Year 4 The additional surface water infrastructure for BOC is expected to be largely constructed by Year 4, including the construction of all of the dams required for the Noise and Visual Bund, completion of the Northern Dam, and construction of the Northern Drain to capture runoff from the Eastern Emplacement Area (see Figure 6). A pipeline will link the Northern Dam with the CHPP Surge Dam so that water can be pumped to the Northern Dam as required. Water quality in the Northern Dam will be managed through a variety of water management strategies to maximise the volume of water that can be discharged under the HRSTS. Key aspects of the additional surface water infrastructure to be constructed by Year 4 are summarised in Table 15. Table 15 Additional Surface Water Management Infrastructure for Year 4 Aspect Indicative Description Existing Water Management Facilities New Clean Water Management Facilities FP1 Dam and FP2 Dam will have been decommissioned and mined through. Swan Lake will be in the process of being decommissioned. Bayswater Pit Water Storage will have been decommissioned and will be being mined through. The Northern Dam will have been commissioned. The Northern Dam includes a clean water weir on the upstream side of the dam with a dead storage of 400 ML. Water will pond upstream of the weir and then spill via a diversion drain around the north side of the Northern Dam to the clean catchment downstream of the dam. The diversion drain will also prevent runoff from the adjacent clean areas from entering the Northern Dam. Mine Water The Northern Drain will be constructed around the Eastern Emplacement Area to collect runoff from the emplacement and direct it to the Northern Dam. Dirty Water Management All surface water infrastructure will have been completed around the Noise and Visual Bund and rehabilitation activities will be underway. Dirty water runoff will be collected in dams around the base of the Bund and managed accordingly. Page 36 of 72

37 Figure 6 BCC Year 4 Water Management System Page 37 of 72

38 7. SITE WATER BALANCE The water management system at BC is integrated, that is, the water from both the open cut operations and underground operations is managed together (as described in Section 3). As such the BC water balance is modelled as an integrated system. Inflows which contribute to the BC water balance include site rainfall runoff, tailings water reclaim, underground flows and water extracted under licence from the Hunter River. The primary source of water for the BC is rainfall runoff which is supplemented by Hunter River water abstracted under licence as required. BC currently store water on site to maintain supply security during dry conditions, and maximise the reuse of mine water and dirty water in the CHPP, for underground mining use and for dust suppression. BC discharge surplus water in accordance with EPL 563 and via the Hunter River Salinity Trading Scheme (HRSTS). Gilbert & Associates Pty Ltd (G&A) have developed a Life-of-Mine water balance model for the BC IWMS which is used to predict surface runoff, evaporation, longer term supply, reliability, storage and discharge requirements. 7.1 Model Overview The structure of the water balance model has been based on the storages and linkages shown in schematic form in Figure 7. The model undertakes a mass balance on all simulated water storages on a sub-daily time step. The model simulates the 20½-year period (1/7/2015 to the end of 2035) to the end of the mine life using the full period of available climatic data for the region from 1892 to One hundred and twenty one possible 20½-year climatic scenarios are simulated using the available climatic record. The results from all scenarios are used to generate water storage volume estimates and other relevant water balance statistics. The model uses output from the Hunter River Integrated Quantity Quality Model (IQQM) in order to simulate variations in Hunter River water flows, from which available water determinations and opportunities for water release in accordance with the HRSTS are computed. The model has been revised to take into account the continuation of BOC. Modelled dam and other storage catchment areas were derived from conceptual future mine stage plans. 1 Data was sourced from the SILO Data Drill for the mine location. The Data Drill is a system which provides synthetic data sets for a specified point by interpolation between surrounding point records held by the Bureau of Meteorology (refer Both rainfall and pan evaporation data were obtained from this source. Page 38 of 72

39 / Bulga Coal Figure 7 Water Management System Schematic / Version: 1.0 Effective: 22/02/201 Page 39 of 72

40 / Bulga Coal Figure 8 summarises the total catchment area reporting to the mine water management system over the simulated mine life. Figure 8 illustrates that the contributing catchment area increases from 28 km 2 to a peak of 33 km 2 in Year 6 before decreasing in the latter half of the simulation period. Any storage which contains fully rehabilitated catchment only was assumed excised (removed) from the water management system from the time that it is fully rehabilitated. The catchment areas were split into different sub-catchment types for rainfall-runoff modelling. Sub-catchments were defined on the basis of vegetation coverage and surface type. Sub-catchment types included in the model were: hardstand (roads, roofed, paved areas), natural surface, open cut, tailings, active spoil, regraded spoil, rehabilitated spoil and coal stockpiles. The Australian Water Balance Model (AWBM - Boughton, 2004) was used to simulate runoff from rainfall on the various catchments and landforms across the mine area. Figure 8 Total Catchment Area over Time The presently approved discharge rate of 185 ML/d is proposed to be supplemented by approximately 500 ML/d from the Northern Dam, once it is commissioned. It was assumed that discharge would not occur if the total volume of water stored on site fell below 2,500 ML. Initial storage volumes, based on recorded water levels as at the start of July 2015 or as a result of 2014 Annual Environmental Management Report (AR) modelling, are summarised in Table 17. Version: 1.0 Page 40 of 72

41 Table 17 Assumed Initial Storage Volumes Storage Initial Stored Water Volume (ML) Existing Bayswater Pit Water Storage 1,040 Proposed Bayswater Pit Tailings Storage 0 Beltana Northern Sumps 0 Beltana Statutory Dam 4.9 Beltana Sumps 1 & 4 0 Beltana Underground 420 Blakefield South Box Cut 0 Blakefield South Statutory Dam 5.8 Bulga Main Pit 20 Bulga East Pit 0 Bulga South Pit 11 C3 Dam 0 CHPP Dam 2,225 Dam Deep Pit 99 Vaux Pit 810 Swan Lake ML Dam 49 Northern Dam 0 FP1 27 FP2 70 Blakefield South Underground 420 Old Tailings Dam 23 Warkworth (Whybrow) Dam 96 ROM A 0 ROM B 0 Sediment Dams S1 to S10, ROM A and ROM B 0 Page 41 of 72

42 7.2 Overall Site Water Balance Model Results Table 18 below summarises the water balance for BCC for the median (50 th percentile) rainfall scenario (totalled over the operation s life). Table 18 Summary Water Balance for Median Rainfall Scenario INFLOWS (ML/year) Rainfall Runoff 3,897 Tailings Water (water liberated as tailings settle) 922 Underground Groundwater Inflow 1,057 Pit Groundwater Inflow 73 Hunter River Licenced Extraction 447 TOTAL 6,395 OUTFLOWS (ML/year) Evaporation 791 HRSTS Release 1,271 External Spill from sediment dams* 15 CHPP Supply 2,146 Underground Supply 559 Haul Road Dust Suppression Supply 1,811 TOTAL 6,592 * Note that sediment dams are designed to spill in events exceeding the 5-day design rainfall event The total volume of water stored at BC is tracked over time and shown in Figure 9 as probability plots, derived from all 121 scenarios, over the simulated mine life. Figure 9 shows that median simulated water stored on site is highest around mid This plot is generally a reflection of the progressive change in catchment area (refer Figure 8 above). Page 42 of 72

43 Figure 9 Simulated Total Water Stored on Site 7.21 Water Supply Reliability Predicted average supply reliability is expressed as total water supplied divided by total demand (i.e. a volumetric reliability). Average supply reliability over all climatic scenarios, as well as the lowest reliability in any one scenario, for the CHPP, underground supply and haul road dust suppression are summarised in Table 19. Table 19 Summary of Modelled Water Supply Reliability CHPP Supply Underground Supply Haul Road Dust Suppression Average 98.3% >99% #1 94.8% Minimum 92.3% >99% #1 78.8% #1 Although no shortfalls were simulated, the inherent uncertainty in the representativeness of low rainfall periods in the historical climate data set used in the model precludes the use of the term 100%. In Table 19 the average reliability is averaged over all scenarios, while the minimum represents the minimum reliability in any scenario. These numbers provide a single measure of water supply reliability for the remaining mine life. It should be noted that reliability predictions are averaged over the mine life and include periods of low and high rainfall through the mine life. Predicted shortfalls vary throughout the mine life with variations in climate and mine layout/catchment area. Figure 10 shows a plot of predicted average annual CHPP supply shortfall. It is important to note that no shortfalls were predicted in most years of most modelled scenarios the plotted average is non-zero in most years because of some shortfall in some scenarios. Figure 10 indicates a low risk of CHPP shortfall in early years with an increased risk later in the operations life. The predicted average shortfalls are low compared with the forecast average CHPP demand of approximately 2,170 ML per year. Page 43 of 72