Bulga Coal Plan
BULGA COAL WATER MANAGEMENT PLAN EPBC APPROVAL 2012/6637
Table of Contents
Bulga Coal Water Management Plan ...... 1 Declaration of accuracy ...... 3 1. INTRODUCTION ...... 4 1.1 Purpose ...... 4 1.2 Scope ...... 5 1.3 Objectives ...... 5 2. PLANNING REQUIREMENTS ...... 7 2.1 Overview ...... 7 2.2 Development Consent Conditions ...... 7 2.3 Mining Leases ...... 16 2.31 Mining Lease (ML 1547) ...... 16 2.32 Mining Lease (ML 1494) ...... 16 2.33 Mining Lease (ML 1674) ...... 17 2.34 Mining Lease (CL 224) ...... 18 2.4 Exploration Licences ...... 18 2.41 Exploration Licences A450, A447, EL5461, and EL5277 ...... 18 2.5 Licences ...... 19 2.51 Environmental Protection Licence ...... 19 2.52 Groundwater Licences ...... 19 2.53 Surface Water Licences ...... 19 3. EXISTING SITE OVERVIEW ...... 23 3.1 Introduction ...... 23 3.2 Hydrology ...... 25 3.3 Geology and Hydrogeology ...... 25 4. WATER MANAGEMENT PRINCIPLES ...... 26 4.1 General ...... 26 4.2 Water Management Classes, Design Objectives and Performance Criteria ...... 26 4.3 Current Operational Philosophy ...... 27 5. EXISTING WATER MANAGEMENT SYSTEM ...... 28 5.1 Clean Water Management ...... 28 5.2 Mine Water Management ...... 28 5.21 Underground Mine Water Management...... 31 5.22 Open Cut Pit Water Management ...... 31 5.23 CHPP Water Management ...... 31 5.3 Controlled Discharges ...... 32 5.31 Discharges via Licenced Discharge Points ...... 32 5.32 Future Licenced Discharge Point ...... 32 6. FUTURE WATER MANAGEMENT DEVELOPMENTS ...... 33 6.1 General ...... 33 6.2 Year 1 ...... 34 6.3 Year 4 ...... 36
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7. SITE WATER BALANCE ...... 38 7.1 Model Overview ...... 38 7.2 Overall Site Water Balance Model Results ...... 42 7.21 Water Supply Reliability ...... 43 7.22 Controlled Releases ...... 45 7.23 Hunter River Extraction ...... 46 7.3 Water Efficiency ...... 47 7.4 Water Balance Monitoring ...... 47 7.5 Water Balance Model Review ...... 48 8. EROSION AND SEDIMENT CONTROL ...... 49 8.1 BCC Operations ...... 49 8.2 BOP Construction Phase ...... 50 9. SURFACE WATER MONITORING PROGRAM ...... 51 9.1 Baseline Data ...... 51 9.11 Surface Water Quality ...... 51 9.12 Mine Water Quality ...... 52 9.13 Streamflow ...... 52 9.2 Surface Water Impact Assessment Criteria ...... 53 9.3 Surface Water Monitoring ...... 54 9.31 Surface Water Quality ...... 54 9.32 Onsite Mine Water Quality Monitoring ...... 55 9.33 Stream Health and Channel Stability...... 55 9.34 Private Dams ...... 56 10. GROUNDWATER MONITORING PROGRAM ...... 57 10.1 Groundwater Monitoring Network ...... 57 10.2 Baseline Data ...... 57 10.21 Groundwater Inflows into the Open Cut ...... 59 10.3 Groundwater Impact Assessment Criteria ...... 59 10.4 Groundwater Monitoring ...... 61 10.41 Groundwater inflows into the Open Cut Pit ...... 62 10.42 Seepage from water storages, emplacements and voids ...... 62 10.43 Regional and local aquifers ...... 62 10.44 Groundwater supply in privately owned bores ...... 63 10.45 Groundwater Dependent Ecosystems ...... 63 10.46 Wollombi Brook Baseflow ...... 63 10.5 Groundwater Model Review ...... 63 11. SURFACE AND GROUNDWATER RESPONSE PLAN ...... 64 11.1 Exceedance of Trigger Values ...... 64 11.2 Response Plan ...... 64 11.3 Unforeseen Impacts ...... 67 12. DECOMMISSIONING STRATEGIES ...... 67 13. REPORTING ...... 67 14. REVIEW ...... 68 15. AUDITS AND INSPECTIONS ...... 68 15.1 Internal Audits ...... 68 15.2 External Audits ...... 68
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16. ACCOUNTABILITIES ...... 69 17. COMPLAINTS PROCEDURES ...... 69 18. TRAINING AND AWARENESS ...... 69 19. REFERENCES ...... 70 20. CONTROL AND REVISION HISTORY ...... 70 20.1 Document information ...... 70 20.2 Revisions...... 71
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
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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 Plant (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 376- 8-2003 (the BUO consent). The BCC Water Management Plan (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 Planning & 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 documenting the water balance for the development; o documenting baseline surface water and groundwater flow and quality information for watercourses potentially affected by the development; o describing the water management system including design objectives and performance criteria;
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o detailing the groundwater assessment criteria and trigger levels / performance indicators; o documenting management actions and mitigation measures to minimise the impact of the development; o outlining surface water and groundwater monitoring and reporting requirements; o documenting the process of groundwater model validation and independent review; o outlining a contingency plan to respond to unpredicted impacts and exceedances of assessment criteria; o outlining the reporting and reviewing requirements; and o 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.
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Figure 1 – Locality Plan
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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 376-8-2003 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 1999. 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 8. 2.2 Development Consent Conditions
Table 1 – Relevant Water Management Conditions (DA 376-8-2003) Section Requirement Condition Addressed SCHEDULE 3 - ADMINISTRATIVE CONDITIONS
4A. Within 3 months of any modification to this consent, the Section 15 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
8 - Pollution Except as may be expressly provided by an Environment of Waters 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.
9 - Discharge Except as may be expressly provided by an Environment Section 2.41& Limits Protection Licence or the Protection of the Environment Section 5.3 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
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Section Requirement Condition Addressed
(b) ensure that the discharges from any licensed discharge points comply with the limits in Table 2:
Table 2 – Discharge limits
Pollutant Units of 100 percentile concentration measure limit pH pH 6.5≤ pH ≤ 9.5 Non-filterable mg/litre NFR ≤ 120 residue
Note: This condition does not authorise the pollution of waters by any other pollutants Each year, the Applicant shall: 10 - Site Section 7
Water (a) review the site water balance for the development against Balance 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 11- Flood Wollombi Brook the Flood Exclusion Levee to the satisfaction of the Secretary. Exclusion Flood Exclusion This levee shall: Levee Levee Plan
(a) remain stable under a 1 in a 100 year ARI flood event; and (BSM SD PLN (b) not cause an increase in backwater stream heights in 0068) 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 12- Flood Exclusion Levee, the Applicant shall submit an as-executed Exclusion report, certified by a practising registered engineer, to the Levee Secretary. 13 - The Applicant shall: Section 9.32 Monitoring (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;
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Section Requirement Condition Addressed (b) monitor the quality of the surface water: Sections 9.13 and discharged from the licensed discharge point/s at the 9.31 development; and upstream and downstream of the development; (c) monitor flows in the Wollombi Brook; Sections 9.13 and 9.31 (d) monitor the volume and quality of water inflows to and from Section 9.32 the underground workings; and (e) monitor regional ground water levels and quality in the Section 10 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 Section 10.5 measures;
in consultation with DECCW and NOW and to the satisfaction of the Secretary. 14 - Site Within 12 months of the date of this consent, the Applicant shall This Document Water prepare or update the existing Site Water Management Plan for Management the development in consultation with DECCW, and to the Plan satisfaction of the Secretary. This plan must include:
(a) the predicted site water balance; Section 7 (b) a Surface Water Monitoring Program; Section 9 (c) a Ground Water Monitoring Program; Section 10 (d) a Surface and Ground Water Response Plan; and Section 11 (e) a strategy for decommissioning water management Section 12 structures on the site. 15 - Site The Surface Water Monitoring Program shall include: Section 9.1 Water Management (a) detailed baseline data on surface water flows and quality in Plan the Wollombi Brook and Loders Creek; (b) surface water impact assessment criteria; Section 9.2 (c) a program to monitor surface water flows and quality in the Section 9.3 Wollombi Brook and Loders Creek; and (d) a program to monitor the effectiveness of the Erosion and Section 8 & 9.33 Sediment Control Plan. 16 - Site The Ground Water Monitoring Program shall include: Section 10.1 & Water 10.2 Management (a) detailed baseline data on ground water levels and quality, Plan based on statistical analysis, to benchmark the pre-mining natural variation in groundwater levels and quality; (b) ground water impact assessment criteria; Section 10.3 (c) a program to monitor the volume and quality of ground water Section 10.4 seeping into the underground mine workings; and (d) a program to monitor regional ground water levels and Section 10.4 quality in the alluvial and coal seam aquifers. 17 - Site The Surface and Ground Water Response Plan shall include: Section 11 and Water the Wollombi Brook Management (a) measures to mitigate any adverse impacts on existing water and Monkey Place Plan supply bores or wells in either the Creek Surface alluvial or coal measure aquifer systems;
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Section Requirement Condition Addressed (b) measures to remediate any connective cracking between the water and underground mine workings and groundwater any surface water stream channels, floodplain areas, or the Response Plan alluvial aquifer; (BSM SD PLN (c) measures to address a decrease in throughflow rates caused 0020) 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. 18 - Flood Three months prior to the commencement of construction of the Wollombi Brook Levee Plan flood levee on the northern drainage line, the Applicant shall Flood Exclusion submit a Flood Exclusion Levee Plan for the Secretary’s approval. Levee Plan The Plan shall include: (BSM SD PLN (a) the detailed design and specifications of the levee, including 0068) 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. 19 - Erosion Three months prior to the commencement of construction works Section 8 and Sediment outside the Bulga Complex Water Management System or Control Plan subsidence remediation, the Applicant shall submit an Erosion and Sediment Control Plan for the Secretary’s approval. The Plan 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 Plan 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 Plan is likely to be prepared in stages to coincide with the relevant stages of the development. 20 - Surface Within 12 months of the date of this consent, or prior to the Section 10 and & Sub-surface commencement of longwall extraction in the approved panels, the Wollombi Brook Investigation whichever occurs first, the Applicant shall develop and and Monkey Place & Monitoring implement a surface and subsurface investigation and monitoring Creek Surface and Program program to assess the likely fracturing of geological strata and Groundwater hydraulic property changes above each longwall panel, to the Response Plan satisfaction of the Director- General. This program shall: (BSM SD PLN 0020) (a) assess the impact on groundwater resources and surface expression resulting from underground mining at varying depths;
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Section Requirement Condition Addressed (b) compare the results from all longwall panels against pre- mining 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. 21 - Final At least 5 years prior to the completion of the development, the Section 12 Void Applicant shall evaluate the potential long-term impacts of any Management final pit voids on groundwater resources, and develop an appropriate management plan to the satisfaction of the Secretary.
Table 2 – Relevant Water Management Conditions (DA SSD-4960) Section Requirement Condition Addressed SCHEDULE 3 – ENVIRONMENTAL PERFORMANCE CONDITIONS The Applicant shall ensure that it has sufficient water for all stages Section 7 24 – Water of the development, and if necessary, adjust the scale of mining Supply operations to match its available water supply.
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 25 – Water Section 3 Mt Thorley mine. Transfers Unless an EPL or the EPA authorises otherwise, the Applicant shall 26 – Water Section 1.3 ensure all surface water discharges from the site comply with the Pollution Section 5.3 discharge limits (both volume and quality) set for the development in any EPL; and Section 9 & relevant provisions of the POEO Act of Protection of the Environment Operations (Hunter River Salinity Trading Scheme) Section 10 Regulation 2002.
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 27 – Water Section 4, Table 8 to the satisfaction of the SecretarySecretary. Management Section 5, Performance Section 6, Measures Section 9, Section 10 & Section 11
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Section Requirement Condition Addressed Table 8: Water management performance measures Feature Performance Measure Section 4, Water Minimise the use of clean water on site Section 5, management – Minimise the need for make-up water from external Section 6, General supplies Section 9, Minimise cumulative water impacts with the other Section 10 & mines in the region Section 11 Construction and Design, install and maintain erosion and sediment operation of controls generally in accordance with the series infrastructure 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 Clean water Design, install and maintain the clean water system diversion & to capture and convey the 100 year ARI flood storage Maximise as far as reasonable and feasible the infrastructure diversion of clean water around disturbed areas on site Sediment dams 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 Mine water Design, install and maintain mine water storage storages 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 Overburden Design, install and maintain emplacements to emplacements 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 Chemical and hydrocarbon products to be stored in hydrocarbon bunded areas in accordance with the relevant storage Australian Standards Aquatic and Maintain or improve baseline channel stability riparian Develop site-specific in-stream water quality ecosystem objectives in accordance with ANZECC 2000 and Using the ANZECC Guidelines and Water Quality Objectives in NSW procedures (DECC 2006), or its latest version
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Section Requirement Condition Addressed The Applicant shall prepare and implement a Water Management Section 1 25 – Water Plan for the development to the satisfaction of the Management SecretarySecretary. This plan must: Plan (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 Section 7
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 Section 7.3
measures to minimise water use on site; (ii) Surface Water Management Plan, that includes: Section 9.1
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 Section 5 &
on site, including the: Section 6 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 Section 4
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 Section 9
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: Section 9.3
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 Section 11
criteria, and mitigate and/or offset any adverse surface water impacts of the development; and
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Section Requirement Condition Addressed (iii) Groundwater Management Plan, which includes: Section 10.1 &
detailed baseline data on groundwater levels, yield and 10.2 quality in the region, and privately-owned groundwater bores, that could be affected by the development;
groundwater assessment criteria, including trigger levels Section 10.3
for investigating any potentially adverse groundwater impacts;
a program to monitor and report on: Section 10.4
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 Section 10.4 &
development, including an independent review of the Section 14 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 Section 11
assessment criteria.
SCHEDULE 5 – ENVIRONMENTAL MANAGEMENT, REPORTING AND AUDITING The Applicant shall ensure that the management plans required Section 9.1 & 3 – under this consent are prepared in accordance with any relevant Section 10.2 Management guidelines, and include: Plan (a) detailed baseline data; Requirements (b) a description of: Section 2,
the relevant statutory requirements (including any Section 9.2 & relevant approval, licence or lease conditions); Section 10.3 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 Section 11
comply with the relevant statutory requirements, limits, or performance measures/criteria; (d) a program to monitor and report on the: Section 9.3,
impacts and environmental performance of the Section 10.4 & development; Section 15 effectiveness of any management measures (see c above); (e) a contingency plan to manage any unpredicted impacts and Section 11
their consequences; (f) a program to investigate and implement ways to improve the Section 14
environmental performance of the development over time;
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Section Requirement Condition 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 Section Requirement Condition Addressed Condition 4 The approval holder must submit for the Minister’s approval a This Document Water Management Plan (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 Section 9 &
success of the management actions in the WMP and define Section 10 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 Section 11
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.
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2.3 Mining Leases
2.31 Mining Lease (ML 1547)
Table 4 – Relevant Water Management Conditions (ML 1547) Section Requirement Condition Addressed
MANAGEMENT AND REHABILITATION OF LANDS (GENERAL) Section 4, The lease holder shall provide and maintain to the satisfaction of Section 5, the minister efficient means to prevent contamination, pollution, Section 6 & erosion or siltation of any river, stream, creek, tributary, lake, Section 8 dam, reservoir, watercourse or catchment area or any undue interference to fish or their environment and shall observe any 25 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
The lease holder shall conduct operations in such a manner as not Section 4, to cause or aggravate soil erosion and the lease holder shall Section 5, 30 observe and perform any instructions given or which may be Section 6 & given by the Minister with a view of preventing soil erosion. Section 8 Section 4, (a) Operations shall be carried out in such a way as not to Section 5, cause any pollution to the Hunter River Catchment Area. Section 6 & Section 8 (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 33 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.
(c) The lease holder shall comply with any regulations now or hereafter to be in force for the protection of the said catchment area.
2.32 Mining Lease (ML 1494)
Table 5 – Relevant Water Management Conditions (ML 1494) Section Requirement Condition Addressed
MANAGEMENT AND REHABILITATION OF LANDS (GENERAL)
Operations must be planned and carried out in a manner that Section 8, does not cause or aggravate air pollution, water pollution Section 9 & 18 - (including sedimentation) or soil contamination. For the purpose Section 10 Prevention of of this condition, water shall be taken to include any watercourse, soil erosion water body or ground waters. The licence holder must observe and pollution and perform any instructions given by the Department in this regard.
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2.33 Mining Lease (ML 1674)
Table 6 – Relevant Water Management Conditions (ML 1674) Section Requirement Condition Addressed
Prospecting operations must be carried out in a manner that does Section 8, 12 – not cause or aggravate, air pollution, water(including Section 9 & Prevention of groundwater) pollution, soil contamination or erosion unless Section 10 soil erosion otherwise authorised by a relevant approval, and in accordance and pollution with an accepted mining operations Plan.
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2.34 Mining Lease (CL 224)
Table 7 – Relevant Water Management Conditions (CL 224) Section Requirement Condition Addressed
The Mining operations plan must present a schedule of proposed Bulga MOP mine development for a period of up to 7 years and contain 4 g) 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 Section 4, the Minister efficient means to prevent contamination, pollution, Section 5, erosion or siltation of any river, stream, creek, tributary, lake, Section 6 & dam, reservoir, watercourse or catchment area or any undue Section 8 interference to fish or their environment and shall observe any 25 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 Section 4, pollution of the Hunter Catchment Area Section 5, 33 a) Section 6 & Section 8
2.4 Exploration Licences
2.41 Exploration Licences A450, A447, EL5461, and EL5277
Table 8 – Relevant Water Management Conditions (A450, A447, EL5461 and EL5277) Section Requirement Condition Addressed
The licence holder must not interfere with the flow of water in any This Document 17 Streams stream or watercourse without the prior written approval of the and the and Department, and subject to any conditions that may be Bulga Coal ESCP Watercourses stipulated. (BUL SD PLN 0023)
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Section Requirement Condition Addressed
(a) All operations must be planned and carried out in a manner This Document 18 Erosion that minimises erosion and controls sediment movement. The and the and Sediment licence holder must observe and perform any instructions given Bulga Coal ESCP Controls by the Department in this regard. (BUL SD PLN 0023)
(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).
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 6.5 – 9.5
Total suspended Solids Milligrams per litre 120 (TSS)
2.52 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 Details 20BL166867 Monitoring (mining bore): GW1 – GW10. Total of 16 bores for monitoring purposes.
20BL167776 Monitoring: P1 – P3, P4A, P4B, P5 – P8 and V3. Licence for total of 9 bores for monitoring purposes.
20BL169204 Monitoring: Bore – ACARP Project.
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Groundwater Licence Details 20BL169246 Monitoring: Bore – ACARP Project.
20BL167777 Monitoring: V1, V2, F1 and F2.
20BL168475 Dewatering (mining): Beltana Longwall 1 Borehole. Volume licence limit 500ML.
20BL169347 Mining: Underground workings. Volume licence limit 365ML.
20BL169514 Dewatering (mining): Beltana MG4. Volume licence limit 500ML.
20BL172658 Dewatering (mining): South Bulga MGE1. Volume licence limit 500ML.
20BL172659 Monitoring: WBR180 and WBR181.
20BL172660 Monitoring: WBR182 and WBR183.
20BL172673 Dewatering (mining): South Bulga MGE4. Volume licence limit 500ML.
20BL173014 Monitoring: SBD194, SBD196.
20BL173617 Monitoring Bore - 61//755264
20BL173618 Monitoring Bore - 34//755264
20BL173619 Monitoring Bore - 33//755264
20BL173620 Monitoring Bore - 23//755264
20BL173621 Monitoring Bore - 24//755264
20BL173640 Monitoring Bore - 25//755264
20BL173657 Monitoring Bore - 22//755264
20BL173708 Monitoring Bore - 11//730762 Surface water Licence Details
20BL136823 Stock and Domestic - 7//10022
20BL138084 Domestic - 13//705699
20BL167656 Test Bore - 7//248448
20BL168145 Stock and Domestic - 31//800688
20BL168526 Domestic and Farming - 5//861535
20CA208127 Irrigation: Ex (Hunter River Frontage) License volume limit 282 units
20CA208597 Irrigation: Ex Feeney Property. Licence volume limit 290 units
20CA208638 Irrigation: Ex Fernance Property. License volume limit 188 units
20CA208650 Irrigation: Halkin Estate. Volume license limit 365 units
20CA208694 Irrigation: Ex Smith-Leigh Property . Volume license limit 150 units
20CA208740 Irrigation: Ex McClellan Property. Volume license limit 96 units
20CA208749 Irrigation ex Foate Property. Volume license limit 21ML
20CA208757 Irrigation: Ex Fordwich Hill. Volume license limit 66 units
20CA208759 Irrigation: Ex Fordwich Hill. Volume license limit 9 units
20CA208817 Irrigation: Ex Johnston Property. Volume license limit 125 units
20CA211233 Irrigation Ex Larking Property. Volume license limit 50 units
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Groundwater Licence Details 20CA211235 Irrigation: Ex Smith-Leigh Property. Volume license limit 22 units
20CA211370 Irrigation: Ex Fernance Property. License volume limit 80 units
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Figure 2 – Existing Integrated Water Management System
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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.
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Figure 3 – Existing and Proposed LDPs, Surface Water and Ground Water Monitoring Locations
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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.
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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 Plan (ESCP) (BUL SD PLN 0023).
Table 11 – Water Management Classes, Design Objectives & Performance Criteria Target Design Surface Description and Source(s) Objective / Treatment Water of runoff Performance Classification Criteria
Mine Water Water exposed to coal or used in New mine water Contained within coal processing. Sources of runoff infrastructure will be the mine water may include: designed, installed management and maintained to system. Potential Haul roads contain events up to for controlled Open cut mine pits and including the 100 release from Swan Coal handling and year ARI, 24 hour Lake and the Surge stockpile areas storm event to Dam under the Mine infrastructure areas mitigate the risk of HRSTS and EPL (e.g. workshops, etc.) uncontrolled discharge conditions. active overburden of mine water off-site. emplacement areas, Water from MIAs Generally any new on- (sometimes This water quality is typically at a site mine water contaminated with higher level of salinity in the storages will be hydrocarbons) range of 5000 μS/cm to 8500 suitably lined to a receive additional μS/cm. Generally water at BCC is permeability of treatment by oil typically neutral to slightly <1 x 10-9 m/s and water alkaline with low metal separators concentrations. Water from MIAs (particularly workshops) has the potential to be contaminated with oils & hydrocarbons.
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Target Design Surface Description and Source(s) Objective / Treatment Water of runoff Performance Classification Criteria
Dirty Water Runoff from disturbed areas Diversion / storage Directed to (during both construction and infrastructure appropriately sized operation). Sources of runoff designed, installed (Blue Book) dirty include: and maintained in line water sediment with the Blue Book dams which are rehabilitated overburden (Managing Urban actively maintained emplacement areas, Stormwater: Soils and and kept in a drawn general disturbed areas Construction Volumes down state. Refer (e.g. construction areas, 1 and 2) and BCC to ESCP for further pre-stripped areas, etc.) ESCP (BUL SD PLN details regarding These areas have the potential for 0023). #1 #2 management of moderately elevated salinity and dams elevated TSS.
Clean Water Runoff from areas that are Diversion Maximised as far as undisturbed as well as infrastructure reasonably practical rehabilitated areas where designed, installed and diverted vegetation is established. and maintained to around disturbance convey a 100 year areas and allowed ARI storm event 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, pre- stripped 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 12. 4.3 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.
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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 4. 5.1 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 376-8-2003). 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.
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Figure 4 – Existing Water Management System
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Table 12 – Key Dams in the Mine Water Management System Capacity Function Dam Name (ML)
Dams for Underground Water Supply
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 11 Fire water storage for underground; also feeds equipment. Stat Dam Minimum of 0.2 ML to be kept in the dam for fire water.
Surface Dams
FP 1 (Fill Point 1 42 Water pumped here from open cut pit, as well as Dam 13, CHPP Storage Dam) Surge Dam and Swan Lake. Used as extraction point for dust suppression.
FP 2 (Fill Point 2 70 Collects runoff from rehabilitated area and also water pumped Storage Dam) from haul road sumps. Used as extraction point for dust (Dam 9) suppression.
Dam 3 (Swan 263 Licenced discharge point. Balancing dam between supply to CHPP Lake) 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, 26 Mine water dams at CHPP area, east of Nine Mile Creek. C11, C12
Dams C4, C7, C9, 23 Dirty water dams at CHPP area, east of Nine Mile Creek. C10, X and Y and Billabong
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 13 90 Mine water transfer dam between the open cut, CHPP and underground operations. Supply point for dust suppression.
Underground Storage
Reserve storage 1,000 Reserve storage in the Whybrow goaf. underground
Note: Generally, the capacities given in Table 11 have been sourced from the Bulga Optimisation Project, Environmental Impact Statement, Volume 5, Surface Water Assessment.
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5.21 Underground Mine Water Management 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. Plant 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. 5.22 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. 5.23 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.
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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 Location Limit Identification No.
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 2.51. 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. 5.32 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 m3/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 m3/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.
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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.
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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 Clean water upstream of the extension to the Bayswater Pit will Management initially be directed into the Bayswater Pit until construction of the Facilities 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 Mine Water New dams and channels constructed to the southwest and north Management west to manage runoff from the Noise and Visual Bund. Facilities 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.
Tailings Deep Pit will be used for tailings disposal. Management Capping of the Old Tailings Dam has commenced as part of the development of the Noise and Visual Bund.
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Figure 5 – BCC Year 1 Water Management System
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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 FP1 Dam and FP2 Dam will have been decommissioned and mined Management through. Swan Lake will be in the process of being Facilities decommissioned. Bayswater Pit Water Storage will have been decommissioned and will be being mined through.
New Clean Water The Northern Dam will have been commissioned. The Northern Management Dam includes a clean water weir on the upstream side of the dam Facilities 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 All surface water infrastructure will have been completed around Management 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.
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Figure 6 – BCC Year 4 Water Management System
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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 20121. 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 http://www.longpaddock.qld.gov.au/silo/). Both rainfall and pan evaporation data were obtained from this source.
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Figure 7 – Water Management System Schematic
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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 km2 to a peak of 33 km2 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.
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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 13 76 Deep Pit 99 Vaux Pit 810 Swan Lake 122 60ML 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
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7.2 Overall Site Water Balance Model Results
Table 18 below summarises the water balance for BCC for the median (50th 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 922 tailings settle)
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-2021. This plot is generally a reflection of the progressive change in catchment area (refer Figure 8 above).
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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.
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Figure 10 – Predicted Average Annual CHPP Shortfall
BC would continue to monitor the mine water balance during the course of the operation’s life and use water balance model predictions to forecast the risk and magnitude of any future water supply shortfalls. Contingency measures, such as the purchase of additional water allocation licences on the open market, would be assessed and put in place if warranted. Should a significant shortfall be identified then consultation with DPI Water will take place regarding a water licencing strategy for BC.
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7.22 Controlled Releases Figure 11 shows model predicted average annual (calendar year) releases from Swan Lake, the Northern Dam and the CHPP Surge Dam. Any controlled releases from BC would be made in accordance with the requirements of the HRSTS.
Figure 11 – Predicted Average Annual Release to Hunter River
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7.23 Hunter River Extraction Supply from Hunter River licenced extraction would vary through the mine life. It has been assumed that Hunter River licenced extraction would not occur until the total volume of water stored on site fell below 1,500 ML. Figure 12 shows predicted median, 10th percentile and 90th percentile annual water year (July to June) extraction volumes. The water balance model for the median year indicates that the need for water via the Mount Thorley Water Supply Scheme is within the current High Security Entitlement (HSE) held by BC of 867 ML/year based on 100 per cent allocation.
Figure 12 – Predicted Annual (Water Year) Hunter River Extraction
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7.3 Water Efficiency
The majority of water consumed at BC is sourced from rainfall runoff within the mine disturbance footprint, from groundwater inflow to the underground workings or from water recycled from settling tailings (refer Table 18). Runoff is typically mixed with the more saline groundwater and tailings water within the integrated water management system and reticulated around site for reuse. The collected water is reused in dust suppression (Open Cut and Underground), in the CHPP (coal washing) or lost through evaporation. Alternatively BC may discharge, through the LDPs, under the HRSTS and in accordance with EPL 563. Through preferentially sourcing water from the IWMS and the buffering capacity of the CHPP Surge Dam, there is a reduced need to discharge water off site (via the HRSTS) or to draw water from the Hunter River (refer Table 18). A number of measures to minimise water use on site at BC have been or will be implemented as follows:
Tailings thickening and flocculation and the use of water reclaimed from the tailings storages in preference to using Hunter River water allocations; Storage and use of runoff from disturbed areas in preference to using Hunter River allocations; Use of water reclaimed from underground operations in preference to using Hunter River allocations; Inspections and maintenance of water management infrastructure.
7.4 Water Balance Monitoring
As part of the water management system, BC will monitor water imported to site, water used on site, water discharged from site in accordance with the HRSTS and volumes of water stored on site.
BCC undertake routine monitoring of water usage, water imported to and discharged from the mine and volumes of water stored on site. The data is used to: trend predicted against actual water balance; record stored water inventory; comply with the requirements of the HRSTS; plan for future mine water supply and management; and monitor trends in water use and efficiency. Table 19 provides a summary of the current existing monitoring undertaken at BCC. Naturally, as mining progresses and existing dams are decommissioned and mined though these monitoring locations will alter accordingly.
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Table 19 Water Balance Monitoring Summary Monitoring of Description Location Frequency Discharge Volume discharged Discharge from In accordance with via licenced Swan Lake (LDP3) EPL discharge point and CHPP Surge Dam (LDP4) Imported Water Volume supplied to Inflow to 60 ML Continuous Supply site by licenced Dam extraction from Hunter River. CHPP Water Usage Volume supplied to Flow from Continuous CHPP Bayswater Pit and CHPP Surge Dam Underground Mine Volume pumped Various flow meters Continuous Extraction & Supply from sumps and dewatering bores. Volume supplied to underground from 60 ML Dam. Mine Dust Water drawn from BOC As required Suppression FP1, FP2 and Dam Consumption 13 and used by BOC Water Carts. Rainfall and Rainfall measured BCC weather station Continuous evaporation and evaporation calculated Storage Stored volumes in All main storages At least Monthly all main water shown in Figure 2 storages (level and mine sumps measured; volume calculated)
7.5 Water Balance Model Review
BC review the site water balance annually or with the completion of significant developments to enable effective water management decisions to be made.
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8. EROSION AND SEDIMENT CONTROL
8.1 BCC Operations
An Erosion and Sediment Control Plan (ESCP) (BUL SD PLN 0023) has been prepared to apply to all operational land within Bulga Coal (i.e. BOC, BUO and CHPP) as defined by the Mining Lease boundaries. The ESCP provides guidance to BCC staff and contractors in minimising the potential effects of erosion and its associated impacts as a result of mining operations including land disturbance and subsidence. The ESCP includes prevention and management of erosion impacts as well as implementation of a monitoring program to provide early detection of potential issues and to ensure the controls are working efficiently and effectively. The ESCP fulfils the requirements of the relevant development consent conditions and relevant statutory requirements for the current BCC operations. The objective of the ESCP is to ensure that appropriate procedures and programs of work are in place to: Meet the requirements of the development consents relevant to the operations at the Bulga Coal Complex; Meet the requirements of Managing Urban Stormwater: Soils and Construction (the Blue Book), Volume 1 and Volume 2E – Mines and Quarries (Landcom, 2004 and Department of Environment and Climate Change (DECC), 2008); Meet the requirements of the EPL No. 568 with regards to total suspended solids; Identify activities that could cause soil erosion and generate sediment; Minimise soil erosion and the potential discharge of sediment to downstream waters during mining and recommend erosion and sediment controls in accordance with best management practices; Describe the location, function, and capacity of erosion and sediment control structures; and Ensure erosion and sediment control structures are appropriately maintained. The ESCP should be implemented in conjunction with the Bulga Coal Water Management Plan to ensure that the objectives of the ESCP are met. Surface water quality monitoring is included in the Water Management Plan with erosion and sediment control monitoring included in the Erosion and Sediment Control Plan. The ESC inspections are conducted on a quarterly basis at the same time as site-wide rehabilitation inspections are done. Actions from these inspections are recorded in CMO and remediation or improvements works undertaken as required. Prior to any disturbance activities being undertaken by the site, a Ground Disturbance Permit (GDP) CAA-HSEC-PER-0004 is required to be completed. The purpose of the GDP is to identify and address any potential environmental, community, infrastructure or safety hazards associated with the proposed works. As part of completing the GDP, an ESCP is required to be developed. All erosion and sediment control activities are to be undertaken in accordance with the guidelines from: Managing Urban Stormwater: Soils and Construction Volume 1 (Landcom, 2004) and Volumes 2A - Installation of Services, 2C- Unsealed Roads, and 2E - Mines and Quarries (DECC, 2008) (the Blue Book). Glencore’s internal standard XCN SD ANN 0077 Erosion and Sediment Control Management (Glencore, 2013).
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8.2 BOP Construction Phase
The construction phase for the BOP will overlap with the existing operational mining activities. The BOP will extend the disturbance footprint, and in these new areas and proposed infrastructure areas, construction phase works will be taking place. Additional construction phase erosion and sediment control measures will be carried out in accordance with relevant guidelines for erosion and sediment control, including the relevant volumes of the Blue Book (Landcom, 2004 and DECC, 2008). A specific Construction Soil & Water Management Plan (XC41200113509) has been prepared to address all construction phase aspects of the BOP as well as monitoring and reporting requirements. Detailed ESC Plans will be prepared for BOP construction areas (involving ground disturbance) under the GDP process.
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9. SURFACE WATER MONITORING PROGRAM
The objective of the surface water monitoring program is to provide details of the monitoring undertaken on site to monitor the effects of the Project on existing surface water bodies. The purpose of this monitoring is to assist in detecting if any significant off-site impacts occur as a result of mining and to trigger response plans to adverse impacts. 9.1 Baseline Data
Two primary characteristics of a watercourse that principally determine the environmental value of the watercourse are the quality of the available water and the volume of the water (yield). It should be noted that mining has been ongoing at BCC and other mines in the area for many years, while historic sampling indicates that some of the creeks in the area are naturally saline. Characterisation of the water resource in terms of quality must consider both of these facts. Historical data relating to water quality and flows in Wollombi Brook and Loders Creek catchment areas is summarised below. This data is used as a baseline for on-going monitoring of the impacts of mining activities on surface water in the Wollombi Brook and Loders Creek catchment areas. 9.11 Surface Water Quality The earliest water quality data from the site is recorded in the 1980 Environmental Impact Statement (EIS) (BHP Ltd 1980). Sampling was undertaken at nine points on Loders Creek/Nine Mile Creek, and at various dams in the area. The EC measured in 1980 varies from 2000 µS/cm to 14,200 µS/cm, with an average of 7,100 µS/cm. The salinity was attributed in the 1980 EIS to seepage from the Saltwater Creek coal measures which subcrop in areas of Loders Creek (MER 2013). Water quality in the receiving watercourses has been monitored monthly as part of the operations at BCC since 1994. Water samples have been monitored for pH, total suspended solids (TSS) and electrical conductivity (EC) although data for the current monitoring points on the creek system is only available within the electronic database from January 2004. The surface water monitoring points and locations are outlined in Table 20.
Table 20 – Selected Surface Water Quality Monitoring Points Monitored Since Monitoring Watercourse / Location Point LR1 Wollombi Brook upstream of the village of Broke. January 2004 LR5 Wollombi Brook downstream of the confluence with the January 2004 Southern Drainage Line. W2 Wollombi Brook downstream of LR5, and upstream of W4. January 2004 W4 Wollombi Brook downstream of the confluence with January 2004 Northern Drainage Line. LR2 Monkey Place Creek at Broke Road. January 2004 W8 Loders Creek upstream of confluence with Nine Mile Creek January 2005 and just upstream of Mining Lease Boundary at the lower end of the site. The location of the current existing surface water quality monitoring points are shown in Figure 3. These include numerous sampling locations within the mine water management system, as well as sampling points upstream and downstream of BCC. The surface water quality data for the monitoring points is summarised in Table 21.
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Table 21 Surface Water Quality Monitoring Data (2004 – 2014) Site pH EC (µS/cm) TSS (mg/L) Avg Low High Avg Low High Avg Low High LR1 7.6 6.6 8.8 650 4 9,470 13 1 72 LR5 7.7 6.8 8.4 739 141 3,470 14 2 144 W2 7.5 6.6 8.2 612 139 1,470 12 2 114 W4 7.5 6.5 8.3 659 200 1,760 10 2 42 LR2 7.8 6.3 8.8 2,778 130 6,290 42 3 440 W8 8.3 7.3 9.5 10,027 1,090 22,500 75 5 1,610 9.12 Mine Water Quality Mine water quality is monitored both for internal water management purposes, and to maintain compliance with EPL 563 which prescribes the conditions in terms of water quality for releases as part of the HRSTS – refer to Section 2.51 and 5.3. The location of the current existing mine water quality monitoring points are shown in Figure 3. Mine water quality data is summarised in Table 22.
Table 22 Mine Water Quality Monitoring Data (2008 – 2014) Site pH EC (µS/cm) TSS (mg/L) Avg Low High Avg Low High Avg Low High Beltana 8.6 7.6 9.4 6,177 835 9,630 18 6 45 Stat Dam Swan 9.2 8.0 9.9 4,751 1,270 10,000 22 1 108 Lake (LDP3) Dam 13 9.0 7.9 9.9 5,574 490 10,440 56 3 344 9.13 Streamflow All of the creeks, except Wollombi Brook, that are located within or around BCC are ephemeral and have periods of no flow in between runoff producing rainfall events. Wollombi Brook is generally regarded as perennial, although the brook exhibited very low flows and was frequently dry on the surface during the extended drought from 2002 to 2007. Streamflow gauging stations are maintained on Wollombi Brook by the OEH. The nearest gauging stations to BCC are GS210028 at Bulga township (3.5km downstream of the mine) and GS210135 at Brickmans Bridge (34km upstream of the site). Streamflow is monitored outside BCC because all watercourses onsite are ephemeral. Data is available from the OEH and on the web for the downstream site at: http://waterinfo.nsw.gov.au/water.shtml?ppbm=SURFACE_WATER&rs&3&rskm_url The streamflow data recorded at these two stations is summarised in Table 23.
Table 23 Summary of Wollombi Brook Recorded Streamflow Data Station: GS210028 (Bulga) GS210135 (Brickmans Bridge) Period of Record: 1949 – 20th Jan 2014 1995 – 20th Jan 2014 No. Missing Days: 7,032 456 No. Zero Flow Days: 2,057 1,003 Max. Daily Flow (ML/d): 922,820 64,682 Mean Annual Flow (ML/d): 410 171
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BCC has the potential to impact on annual flow volumes within downstream catchment areas due to the need to manage runoff from disturbed areas, including mining areas and overburden emplacement areas, during the operational and rehabilitation phases. The approved mine layout results in a deeper final void with an associated larger final void extent and as such final void catchment area. Hence BOC will generally reduce catchment areas compared to pre-mining catchments, particularly during the operational phase prior to rehabilitation of the overburden emplacement areas, as follows: Wollombi Brook, estimated at approximately 0.02%; Northern Drainage Line, estimated at approximately 0.1%; Southern Drainage Line, estimated at approximately 2%; and Loders Creek (excluding the Doctors Creek catchment), estimated at approximately 7%. The open cut operations include a number of measures to limit the loss of catchment associated with mining, including diversion of clean water around mine infrastructure areas, and drainage of rehabilitated areas back to the clean catchment where the water quality is suitable for release. Additional measures that will be implemented to reduce the loss of catchment area include the following: The overburden emplacement areas will be rehabilitated as soon as practicable. The strategy of concurrent rehabilitation will minimise the duration for which catchment is lost during the operational phase. Once rehabilitation is established and runoff water quality has been determined to be ok, areas will be allowed to return water to the surrounding environment. The final landform will include channels to drain as much of the rehabilitated areas back to the Loders Creek and Wollombi Brook catchments as is practicable, reducing the loss of catchment due to the presence of the final void. It is important to note that the changes in annual flow volumes with the proposed final landform are considered to be small within the context of ephemeral streams, with the change in flows being less than the seasonal and annual variations in flow volumes comparing dry years to wet years. Hence BOC is considered likely to have limited impact on ecosystems and downstream users as the predicted impact is within the natural variation of the existing creek systems. 9.2 Surface Water Impact Assessment Criteria
The Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC, 2000) apply to the quality of both surface water and groundwater as they have been developed to protect environmental values relating to uses such as irrigation and stock use. The trigger values are not assessment criteria but are used to initiate investigations into the surface water quality as reported by the monitoring program. ANZECC (2000) recommends that wherever possible, site-specific data should be used to define trigger values for physical and chemical factors which can adversely impact the environment. Trigger levels developed in accordance with the guidelines are statistically- based, accommodate site-specific anomalies and use a statistical measure to represent the variability of natural conditions. A minimum of two years of monthly data at the reference site is required before a valid trigger value can be established. Monitoring data exists for BCC since 2007 however due to the ephemeral nature of the surrounding watercourses there is insufficient data to develop triggers in accordance with the guidelines, with the exception of monitoring point LR2. Whilst there is insufficient data for other sites, temporary trigger levels have been and will be continually refined as further data becomes available. Trigger values for pH have been determined by using 80th and 20th percentile, while the trigger levels for EC and TSS are provided by calculating the 80th percentile i.e. upper trigger level in accordance with the ANZECC (2000) guidelines and statistical analysis.
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Table 24 presents the trigger levels
Table 24 Impact Assessment Trigger Values Surface Water (2007 – 2014) pH EC (µS/cm) TSS (mg/L) Monitoring Watercourse Lower Upper Location 80th%ile 80th%ile 20th%ile 80th%ile Monkey Place LR2 7.39 7.91 3022 40.8 Creek Wollombi LR1#2 Reference site upstream of the operations (no impact triggers) #1 Brook LR5 7.53 8.02 847 10 W2 7.34 7.67 711.4 9 W4 7.33 7.76 746.6 9.6 Loders Creek#1 W8 7.83 8.35 13800 53
#1 Due to the ephemeral nature of the watercourses there is insufficient data to develop triggers in accordance with the guidelines for sites other than LR2. Hence only temporary trigger values have been adopted. #2 LR1 is upstream of the operations and is used as a reference site Where the surface water monitoring reveals a result outside the above trigger levels, the Response Plan will be activated as detailed in Section 11. 9.3 Surface Water Monitoring
Ongoing surface water quality monitoring will aim to: Continue to record and document the existing water qualities upstream and downstream of BCC so as to highlight any areas of concern or impact. Review and monitor the performance of erosion and sediment controls at construction areas. Continue the reporting of monitoring results in the EPL Annual Review and AR which includes an assessment of results in terms of off-site impacts as a result of mining.
9.31 Surface Water Quality
Surface water quality monitoring is currently undertaken at various upstream and downstream locations on the creeks impacted by BCC. Additional surface water quality monitoring locations will be established as part of continued BOC operations and samples will be tested as per the existing arrangement with respect to parameters and frequency. These include new monitoring points on Loders Creek to address new disturbance areas and proposed discharge points, reinstatement of monitoring points on the Northern Drainage Line previously sampled (discontinued due to limited flow), and new monitoring points on the Southern Drainage Line to replace monitoring points that will be lost due to the proposed construction of the Noise and Visual Bund. Table 25 summarises the existing and new future surface water quality monitoring undertaken at sites within and surrounding BCC.
Table 25 Surface Water Quality Monitoring Program Site Location Parameters Frequency Existing Sites LR1 Wollombi Brook pH, TSS, EC, flow condition Monthly LR2 Monkey Place Creek pH, TSS, EC, flow condition Monthly#1 LR5 Wollombi Brook pH, TSS, EC, flow condition Monthly W2 Wollombi Brook pH, TSS, EC, flow condition Monthly W4 Wollombi Brook pH, TSS, EC, flow condition Monthly W8 Loders Creek pH, TSS, EC, flow condition Monthly#2
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Site Location Parameters Frequency New Future Sites NDL1 Northern Drainage pH, TSS, EC, flow condition Monthly#1 Line SDL1 Southern Drainage pH, TSS, EC, flow condition Monthly#1 Line NMC1 Nine Mile Creek pH, TSS, EC, flow condition Monthly#1 LC1 Loders Creek pH, TSS, EC, flow condition Monthly#1 LC2 Loders Creek pH, TSS, EC, flow condition Monthly#1 #1 Flow permitting. #2 Water quality on Loders Creek measured daily when discharging under HRSTS. Continuous monitoring applies to the EC and discharge monitoring and is defined as a device Electronic level sensor and continuous logger. The retained existing and new future surface water quality monitoring points are shown in Figure 3.
9.32 Onsite Mine Water Quality Monitoring
On-site mine water quality monitoring is currently undertaken at various locations within the BCC for internal water management purposes, and to maintain compliance with EPL 563 which prescribes the conditions in terms of water quality for releases as part of the HRSTS. Table 26 summarises the current existing and new future onsite mine water quality monitoring undertaken at sites within the BCC.
Table 26 Onsite Mine Water Quality Monitoring Program Site Location Parameters Frequency Existing Sites D9 FP2 pH, TSS, EC, Dam Level, Oil and grease Monthly D13 Dam 13 pH, TSS, EC, Dam Level, Oil and grease Monthly LDP3 Swan Lake (LDP3) pH, TSS, EC, Dam Level, Discharge Monthly Volume, Oil and grease Continuously under discharge.
TSS and pH daily when discharged. LDP4 CHPP Surge Dam pH, TSS, EC, Dam Level, Discharge Monthly (LDP4) Volume, Oil and grease Continuously under discharge.
TSS and pH daily when discharged.
9.33 Stream Health and Channel Stability
A program to monitor creek line channel stability and health of riparian vegetation within Nine Mile Creek has commenced and will continue throughout the mine life. The monitoring program will be extended to include Loders Creek and Wollombi Brook. The monitoring is undertaken on downstream watercourses to ensure their stability is not impacted on by the existing or proposed discharges. Monitoring of the drainage lines includes: A channel stability assessment encompassing: o Documenting general observations of water quantity and quality;
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o Documenting locations and dimensions of significant erosive or depositional features so that any subsequent changes can be evaluated quantitatively;
o Establishing multiple photographic points at representative locations, so that photos can be taken over multiple inspections in a repeatable manner;
o Written descriptions of the stream at each of the photographic points, focussing on evidence of erosion and exposed soils;
An AUSRIVAS assessment encompassing: o Habitat assessments;
o Water quality monitoring; and
o Aquatic flora and fauna surveys.
Results of monitoring data will be reviewed and compared to previous rounds of monitoring to assess whether there is any degradation of the riparian vegetation or stream channel. Where degradation or adverse erosion is occurring, additional investigations will be undertaken to assess whether the impacts may be associated with the operation of the mine and ameliorative actions undertaken as required.
Table 26 Stream Health Performance Indicators Trigger Level Negligible change in the ecosystem A floristic change that can be correlated with a functionality of the riparian vegetation hydrological change A 30% decline in species assemblage or abundance of Negligible change in bird diversity and birds utilising riparian vegetation (Can narrow this down abundance to niche specialists also) Negligible change in frog diversity and A 30% decline in species assemblage or abundance of abundance frogs utilising riparian vegetation Note: the trigger levels nominated are subject to change with ongoing monitoring and are preliminary values only.
9.34 Private Dams
The water levels in privately owned dams will be monitored in accordance with the relevant Private Property Subsidence Management Plans (PPSMP), Subsidence Monitoring Plan and the Surface Safety Subsidence Management Plans for the approved longwalls BSLW7 – BSLW9 Blakefield South Mining Area.
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10. GROUNDWATER MONITORING PROGRAM
The aim of the groundwater monitoring program is to provide the early warning of the potential changes in groundwater levels and quality which exceed trigger levels determined for the site and are outside of the predicted (modelled) values. The groundwater monitoring program started at BCC in 1998, and has been expanded since, with some monitoring bores decommissioned and new ones installed as the mining operations expanded to the south and have started extracting from different seams. The groundwater monitoring program currently comprises: Bi-monthly water level monitoring in all standpipe piezometers including the measurement of electrical conductivity (EC) and pH; Continuous monitoring of pressure heads in 15 vibrating wire piezometers; Continuous monitoring of water levels in 22 standpipe piezometers which are equipped with dataloggers; and Comprehensive geochemical sampling and analysis undertaken on a half yearly basis in all 49 standpipe piezometers (including major ions and metals). Water quality parameters tested onsite include temperature, turbidity and colour. Testing of EC and pH are conducted by NATA accredited laboratories. In addition, groundwater chemical analysis of major ions is conducted biannually. Water samples are collected using a polyvinyl chloride (PVC) bailer and are then transferred into bottles for analysis. Field measurements are duplicated from separate bailed samples to ensure that results are constant. In accordance with the requirements of Development Consent (DA 376-8-2003), the existing Wollombi Brook Groundwater Contingency Plan BSM SD PLN 0020 (GCP) will be modified to include the Monkey Place Creek Alluvial Aquifer (to become the Wollombi Brook and Monkey Place Creek Surface and Groundwater Response Plan). This GCP covers the monitoring and response of the effects of underground mining within the Blakefield South mining area on the Wollombi Brook and Monkey Place Creek. 10.1 Groundwater Monitoring Network
BCC has a comprehensive baseline groundwater monitoring network within and outside of the mine footprint area with 49 groundwater monitoring points (see Figure 3). The monitoring network comprises both standpipe piezometers and multilevel vibrating wire piezometers installed in all hydrostratigraphic units. 10.2 Baseline Data
Baseline groundwater level and quality data collected at the piezometers shown on Figure 3 are summarised in Table 27.
Table 27 – Baseline Groundwater (1998 to Present) Level and Quality Monitoring Piezometer Water Level (mAHD) pH EC (µS/cm) No. Low High Low High Low High Broke Area Alluvials GW1 84.73 89.74 6.45 7.67 762 8830 GW2#1 82.56 85.29 6.59 7.55 615 5051 GW3 74.48 77.28 6.48 8.00 210 6300 GW4#1 77.97 79.78 6.40 7.74 644 5730 GW5#1 79.72 81.36 6.62 8.07 1660 6320 GW6 72.21 75.60 6.92 8.19 4440 8450 GW7 63.21 74.75 6.37 9.05 141 6790 GW8 70.57 72.81 5.60 7.63 4200 6850
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Piezometer Water Level (mAHD) pH EC (µS/cm) No. Low High Low High Low High GW9 70.84 73.37 6.14 9.73 100 4790 GW10 69.76 73.32 6.50 8.08 820 11400 V3 65.49 70.23 6.70 8.20 344 1831 Broke Area Wollombi Seam P2 67.33 70.58 6.91 8.62 2480 14700 P5A 67.84 73.56 6.50 9.07 265 7540 P6A 68.68 85.00 6.20 8.61 13 7410 Northern Area Shallow Alluvials F1 61.26 65.83 6.51 8.19 265 1302 F2 63.31 65.78 6.68 8.75 180 2044 WBR50A#2 58.18 62.91 6.20 8.27 130 15110 V1#2 63.14 65.44 6.70 8.13 880 1650 V2#2 59.3 63.25 5.81 8.15 101 2430 SBC/Broke Area Lower Whybrow Seam P1 61.28 71.76 6.97 8.48 7760 15900 P6B 54.48 80.20 6.23 7.96 120 1350 P7B 66.17 73.72 6.63 9.87 120 4500 P8 63.26 84.60 6.75 10.16 1192 8750 Northern Area Lower Whybrow Seam WBR50#2 24.90 63.77 6.00 8.75 100 9120 Northern Alcheringa Seam WBD62A#2 62.70 66.83 6.40 8.34 203 1196 Beltana Area Miscellaneous Bores and Wells Dwyers#3 61.09 64.10 6.95 8.07 210 1659 Fernance#2 59.74 66.01 6.90 8.60 490 1540 McG1#2 89.86 94.89 6.80 8.62 150 1280 White1#2 63.36 65.65 6.52 8.20 500 2910 WBR15#2 62.61 67.17 6.48 8.60 293 991 Beltana Area NPZ NPZ3-A#4 56.02 73.12 6.49 8.11 100 2190 NPZ3-B#4 61.24 67.60 7.20 8.20 196 1240 NPZ4-A#4 60.26 64.29 6.52 7.98 573 1193 NPZ4-B#4 45.32 55.13 7.20 8.41 259 1430 NPZ5-A#4 63.22 64.88 6.52 8.02 240 894 NPZ5-B#4 41.16 61.30 6.30 8.21 359 2820 NPZ7-1#4 58.49 67.07 6.30 8.39 109 1320 NPZ7-2A#4 62.68 64.71 6.57 7.90 270 2360 NPZ7-2B#4 45.36 67.02 6.51 8.33 150 1420 NPZ7-3A#4 62.78 66.60 6.92 9.10 846 2580 NPZ7-3B#4 59.52 69.20 6.96 8.40 817 14332 Wollombi Alluvials and Shallow Coal Measures WBD160#6 64.34 65.30 6.77 7.89 807 1540 WBR180#5 34.30 55.93 6.90 8.04 10400 21700 WBR181#5 59.66 61.59 7.13 8.18 2280 2680 WBR182#5 62.37 64.06 7.40 9.46 1110 1600 WBR183#7 58.96 64.35 6.97 8.03 2480 3500 SBD196#8 67.96 69.25 6.80 7.86 1440 4000 WBR240#9 59.20 59.75 7.6 7.6 17700 17700 WBR241#9 60.52 60.88 6.9 6.9 524 524
#1 During Q1 2014 these sites were added to the sampling schedule. These sites have been recommissioned after monitoring ceased in 2002.
#2 These sites were added to the sampling schedule in 2002.
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#3 This site was added to the sampling schedule in 2003.
#4 These sites were added to the sampling schedule in 2005.
#5 These sites were added to the sampling schedule in 2007.
#6 This site was added to the sampling schedule in 2008.
#7 This site was added to the sampling schedule in 2009.
#8 This site was added to the sampling schedule in 2012.
#9 These sites were added to the sampling schedule in March 2014. Comprehensive groundwater quality analysis is provided in AR and in the groundwater assessment for each of the longwall panel following its completion.
10.21 Groundwater Inflows into the Open Cut
Groundwater inflows for the mining operations were simulated as part of the groundwater studies undertaken for the BCC EIS for the Bulga Optimisation Project (MER, 2013). Currently approved BUO will have depressurised the coal measures in advance of the open cut operations. Therefore, the groundwater inflows that would have been intercepted by the expansion of the pit, will be reporting to the approved underground mine instead (MER, 2013). The results of the groundwater prediction modelling for the optimised open cut are shown in Table 28 (MER, 2013).
Table 28 – Predicted Groundwater Inflows into Open Cut
Year Mine Water Inflows into Open Cut (ML/year)
2015 73
2020 110
2025 63 2030 26 The minor inflow into the open cut pit is the result of deepening of the pit and low permeability of non-coal strata and low groundwater storage in the deep coal measures. The predicted groundwater inflow into the pit in 2014 was estimated at around 18 ML/year. This amount of seepage is considered negligible and the pit is currently operating in dry conditions, with the seepage not being evident as a discrete inflow. 10.3 Groundwater Impact Assessment Criteria
The Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC, 2000) apply to the quality of both surface water and groundwater as they have been developed to protect environmental values relating to uses such as irrigation and stock use. The trigger values are not assessment criteria but are used to initiate investigations into the groundwater quality as reported by the monitoring program. ANZECC (2000) recommends that wherever possible, site-specific data should be used to define trigger values for physical and chemical factors which can adversely impact the environment, hence the impact assessment criteria for existing and proposed piezometers include piezometric pressure (measured as depth to water level), and water quality parameters pH and EC. Vertical pressure gradients are also monitored in a number of additional piezometers constructed in the buffer zone between the alluvial lands and the longwall panel area.
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According to ANZECC (2000) and Australian guidelines for water quality monitoring and reporting, the recommended trigger-based approach for physio-chemical stressors is defined as follows: A trigger for further investigation will be deemed to have occurred when the median concentration of n independent samples taken at a test site exceeds the eightieth percentile of the same indicator at a suitably chosen reference site. Trigger levels defined in such a way are statistically-based, accommodate site-specific anomalies and use a statistical measure to represent the variability of natural conditions. ANZECC (2000) recommends that wherever possible site-specific data are used to define trigger values for physical and chemical factors which can adversely impact the environment. A minimum of two years of monthly data at the reference site is required before a valid trigger value can be established. Monitoring data exists for BCC since 1998 providing a sufficiently long and good quality dataset to define site specific trigger levels. A full review of trigger levels was undertaken for all monitored piezometers to update the trigger levels set in 2011 (RPS Aquaterrra, 2012). Trigger values for pH have been determined by using 80th and 20th percentile, while the trigger levels for EC are provided by calculating the 80th percentile i.e. upper trigger level in accordance with the ANZECC (2000) guidelines and statistical analysis. The baseline water level data was also analysed to derive trigger levels for the bores installed in the strata other than Permian coal measures such that they represent 5% reduction of saturated thickness, based on the minimum of the historical baseline monitoring. The confined Permian strata will be depressurised as a result of mining and therefore the trigger levels for those bores are not considered relevant. Table 29 presents the trigger levels as extracted from the BCC Groundwater Management Plan (GWMP) (David, 2014).
Table 29 Impact Assessment Trigger Values for Piezometers Piezometer Water Level (mAHD) pH EC (µS/cm) No. Trigger Value 20th %ile 80th %ile 80th %ile Trigger Value Trigger Value Trigger Value Broke Area Alluvials#1 GW1 NA2 6.8 7.3 3244 GW3 73.99 6.7 7.2 6000 GW6 72.19 7.3 7.8 7830 GW7 63.29 6.7 7.2 3786 GW8 70.00 6.6 7.0 5940 GW9 70.34 6.7 7.2 4182 GW10 69.14 7.10 7.6 10332 V3 64.99 7.1 7.7 1566 Broke Area Wollombi Seam P2 NA1 7.6 8.0 12742 P5A NA1 7.2 8.2 5730 P6A NA1 6.9 8.0 2724 Northern Area Shallow Alluvials F1 60.83 7.1 7.5 833 F2 62.93 7.1 7.4 1676 WBR50A NA1 7.2 7.7 14262 V1 62.53 7.3 7.6 1560 V2 58.7 6.5 7.1 922 SBC/Broke Area Lower Whybrow Seam P1 NA1 7.4 7.8 14294 P6B NA1 6.6 7.0 1350
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Piezometer Water Level (mAHD) pH EC (µS/cm) No. Trigger Value 20th %ile 80th %ile 80th %ile Trigger Value Trigger Value Trigger Value P8 NA1 7.5 9.5 4030 Northern Area Lower Whybrow Seam WBR50 NA1 6.7 8.2 8382 Beltana Area Miscellaneous Bores & Wells Dwyers 60.54 7.2 7.7 1396 Fernance 59.27 7.2 7.9 1405 McG1 NA2 7.5 8.00 1280 White 1 62.22 7.0 7.4 2910 WBR15 62.16 6.7 7.3 991 Beltana Area NPZ NPZ3-A NA1 7.3 7.7 1361 NPZ3-B NA1 7.3 7.5 968 NPZ4-A NA1 7.0 7.3 723 NPZ4-B NA1 7.0 7.7 1248 NPZ5-A NA1 6.9 7.3 894 NPZ5-B NA1 7.1 7.6 2646 NPZ7-1 NA1 6.84 7.7 1240 NPZ7-2A NA1 7.0 7.6 1840 NPZ7-2B NA1 7.1 8.0 1290 NPZ7-3A NA1 7.2 7.6 2060 NPZ7-3B NA1 7.4 7.8 1292 Wollombi Alluvials and Shallow Coal Measures#2 WBD160 NA2 6.9 7.3 1320 WBR180 NA1 7.1 7.5 20280 WBR181 59.65 7.3 7.6 2596 WBR182 62.16 7.9 8.51 1473 WBR183 NA1 7.0 7.4 3270 WBR240 NA1 6.5 8 ND WBR241 60.20 6.5 8 ND
#1 During Q1 2014 sites GW2, GW4 and GW5 were added to the sampling schedule and hence no trigger values have been established as yet. #2 No trigger values have been established for SBD196 as yet. NA1 Trigger levels are not set for Permian Coal measures due to depressurisation resulting from seam extraction. NA2 Trigger levels are not defined as depth of bore is unknown. ND Not determined - insufficient data available to trigger levels assessment. Where the groundwater monitoring reveals a result outside the impact assessment criteria the Response Plan will be activated as detailed in Section 11. 10.4 Groundwater Monitoring
The objectives of the comprehensive groundwater monitoring program are to identify any decline in groundwater levels and deterioration in groundwater quality or depressurisation as a result of mining operations that exceeds the set trigger levels and may impact on local or regional groundwater systems and groundwater dependent ecosystems. Monitoring is undertaken at the bores/piezometers bimonthly for physicals (depth, pH, EC) and biannually for comprehensive geochemical sampling. Bore locations are shown in Figure 3. Each month the water extraction records from underground operations is recorded in the site Water Accounting Framework spreadsheet. These records are then used to update the site water balance in the Annual Report. The quality of water coming from the underground
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Bulga Coal Plan workings, via dewatering bores, is tested biannually along with the piezometers when the full geochemical sampling is performed. The results of water quality monitoring are reported quarterly on the BC website and annually in the BC Annual Report, which is also available on the website. The AR includes an assessment of results in terms or regional site impacts as a result of mining as well as trends against predictions. At the completion of each underground longwall panel, End of Panel groundwater and subsidence reports are written which assess the impact on groundwater resources and surface expression resulting from underground mining at varying depths. These reports also compare the results from previous panels against pre-mining conditions, to assess the level of variability of fracture and changes in hydraulic properties between panels. These reports are available on the BC website. Monitoring of the regional ground water levels and quality in the alluvial, coal seam, and inter-burden aquifers will be maintained for the entire mining period and at least 10 years after mining.
10.41 Groundwater inflows into the Open Cut Pit
Current groundwater contribution to open pit (simulated 18 ML/year) is negligible and not measurable. The inflow occurs as seepage from the walls, is lost during blasting, evaporates prior to reaching the pit floor or is incorporated with the considerable rainfall run off (3000 to 4000 ML/annum) that reports to the Open Cut Pit. The groundwater inflow into the pit is predicted to increase to 110 ML/year (0.3 ML/day) in 2020 which is in the order 2% of total pit water inflows. This is not considered to be a significant volume of water and is below the accuracy of the current water balance. Given the very low contribution of potential groundwater inflow into the pit and inability to separate ground and surface water inflows it is proposed to adopt the groundwater model inflows as outlined in Section 10.21.
10.42 Seepage from water storages, emplacements and voids
Water storages and emplacement areas will be monitored for potential seepage using the existing groundwater monitoring network with the addition of some shallow standpipe piezometers for the proposed Northern Dam. The monitoring schedule will be the same as for other piezometers in the monitoring network. A review of the results will be undertaken quarterly and if seepage/leachate loss is suspected, based on the monitoring program, a hydrogeological expert will be engaged to review the suspected loss and if required make recommendations to reduce the loss. 10.43 Regional and local aquifers The groundwater model predicts the water table within the shallow alluvium to remain unaffected by leakage to the depressurised coal seams. Therefore, current monitoring of the groundwater pressure response within the coal measures and the water table within shallow alluvial strata is considered sufficient and will continue as per the current schedule. A quarterly review of water level and quality monitoring data will be undertaken and will include consideration of relevant meteorological and rainfall data. Measured values will be compared to background trends and an investigation of potential cause undertaken when water quality parameters and groundwater levels exceed the impact assessment trigger values in accordance with the response plan. If monitoring of these parameters is proposed to be altered or discontinued, BCC will consult with DPI Water and the DP&E during the revision of the monitoring program. Monitoring results will be reported in the AR. Reporting will include a comparison of water quality trends with those of previous years and will highlight any results that are
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Bulga Coal Plan inconsistent with trends in baseline data. All monitoring data will be retained in an appropriate format on site and will be used to review the effectiveness of the BCC water management system on an ongoing basis. 10.44 Groundwater supply in privately owned bores As the impact to alluvium is predicted to be negligible, the impact on the groundwater supply bores on neighbouring properties is also expected to be negligible (MER, 2013). Despite this, BCC will continue the extensive monitoring program on site to ensure that any changes to groundwater pressures, levels and quality are recorded and managed prior to any potential impact reaching private bores. These monitoring results will be reviewed every quarter and reported in the AR. BCC receiving a complaint or expression of concern from any approval or licence holder suspecting their supply has been impacted by the Bulga mining operations will trigger a full investigation into the matter by BCC in consultation with DPI. If the Bulga mining operations do adversely impact on an approval of licence holder water supply Bulga Coal will make good the supply. 10.45 Groundwater Dependent Ecosystems Mining operations are not predicted to impact on the Groundwater Dependent Ecosystem (GDE) located at some reaches of Wollombi Brook and Loders Creek and hence there is no monitoring program proposed for the GDE’s during mining operations Shallow monitoring bores will be installed in the Loders Creek alluvium and will provide baseline data, allowing for early detection of altered baseflow contribution to the creek and provide information on any potential impact from seepage from water storages or emplacement areas on the alluvium. 10.46 Wollombi Brook Baseflow Groundwater modelling indicates no impact to the Wollombi Brook alluvium as a result of continued BOC operations. Nevertheless, to provide early warning of any potential losses from the Wollombi Brook alluvium, BCC will use the two OEH streamflow gauging stations located upstream and downstream of the operation and will assess the changes in baseflow contribution based on the long term historical data available for those two stations. This information will be reported in the AR. In addition, groundwater monitoring bores installed in the alluvium will provide early warning of any potential changes in groundwater levels and therefore changes to flow. The review of groundwater monitoring data will occur quarterly. 10.5 Groundwater Model Review
BCC will undertake validation of the groundwater model using the groundwater data collected since the last review. Should the observed results differ appreciably from the calibrated model; the model may need to be re-calibrated. The groundwater model will be validated and re-calibrated (if needed) on a three yearly (to coincide with the independent environmental audit) or as needs basis, and in consultation with DPI Water. When completed, the groundwater model calibration with be supplied to DPI Water. In preparation for this audit the validation and re-calibration of a groundwater model will be reviewed by an independent suitably qualified, independent hydrogeologist in accordance with the groundwater modelling guidelines (Barnett et al, 2012).
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Bulga Coal Plan
11. SURFACE AND GROUNDWATER RESPONSE PLAN
Potential groundwater impacts resulting from the mining process largely relate to the shallow alluvial aquifer systems that are used for irrigation water supply. The response plans for such impacts are detailed in subsequent sections below. 11.1 Exceedance of Trigger Values
If, as a consequence of the surface water and groundwater monitoring programs for offsite locations, any samples or test results exceed the trigger values then the Environment and Community Manager will be responsible for initiating an investigation into the causes.
If any surface water and/or groundwater triggers are reached then DP&E and DPI Water will be notified in writing via email to [email protected] and [email protected] If regular exceedances occur, the Environment and Community Manager is to notify and formulate corrective actions in consultation, as required, with any relevant stakeholders. 11.2 Response Plan
A Trigger Action Response Plan (TARP) has been developed to outline BCCs response and identify required management actions to potential exceedances of surface water and groundwater trigger values. The TARP is provided as Table 31 below, and will be reviewed and may be revised as conditions at BCC change or new risks are identified.
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Table 31 – Trigger Action Response Plan Key Element Trigger Response Exceedance of EPL Discharge pH outside range BCC to investigate the exceedance and as much as is practical identify the cause, potential remediation and or preventatives measures. Criteria 6.5-9.5 Report results to senior management and where relevant to the EAP as per the conditions of the EPL. TSS >120 ml/L 1. Potential remediation of drainage line such as reestablishment of riparian flora. 2. Preventative measures may include an improved discharge water quality monitoring. Impacts on Channel Stability BCC to investigate the identified adverse impacts on channel stability and as much as is practical identify the cause, potential remediation and or preventatives measures.
See Section 9.33 Potential feasible remediation and preventative actions may include undertaking erosion control works and reestablishment of riparian flora.
BCC to report results of the investigation to senior management and include in the Annual Review. Stream and riparian vegetation Section 9.33 and BCC to investigate the identified adverse impacts on riparian vegetation health and as much as is practical identify the cause, potential remediation and or health Table 26 preventatives measures.
Potential feasible remediation and preventative may include undertaking erosion control works and reestablishment of riparian flora.
BCC to report results of the investigation to senior management and include in the Annual Review. Loss of Baseflow in Wollombi See Section BCC to investigate any identified or suspected losses in baseflow higher than the approved levels and as much as is practical identify the cause, potential Brook higher than the 10.46 remediation and or preventatives measures. approved levels BCC to report results of the investigation to senior management, DoPE, DPI and DOE and include in the Annual Review.
In the event of an identified impact to the baseflow the Wollombi Brook Groundwater Contingency Plan (BSM SD PLN 0020) response actions would be initiated. Potential feasible action could include relinquishment of water allocations and or installation of a grout curtain. Surface water monitoring See Section 9.2 BCC to investigate the exceedance and as much as is practical identify the cause, potential remediation and or preventatives measures. results are outside the relevant and Table 24 quality criteria BCC to determine if harm to the environment has occurred as a result of BCC activity and if so report to the EPA as required under the conditions of the EPL.
Potential feasible remediation and or preventative measures may include undertaking erosion control works and or improving the vegetative cover.
BCC to report results of the investigation to senior management and include in the Annual Review. Loss of Groundwater See Section 10.3 BCC to investigate any identified or suspected loss of groundwater availability and as much as is practical identify the cause, potential remediation and or Availability and Table 29 and preventatives measures. Section 10.4 If the Bulga mining operations do adversely impact on an approval of licence holder water supply Bulga Coal will make good the supply.
Potential feasible options for supplementing an impacted supply would be the establishment of supplementary groundwater abstraction points on BCC owned properties and reticulation to the effected party.
BCC to report results of the investigation to senior management, DoPE, DPI and DOE and include in the Annual Review. Increased Groundwater Inflows See Section BCC to investigate the exceedance and as much as is practical identify the cause, potential remediation and or preventatives measures. into Open Cut Pit or 10.21 and 10.41 Underground Workings BCC to report results of the investigation to senior management, DoPE, DPI and DOE and include in the Annual Review.
If the groundwater inflows exceeded the licenced quantities BCC would purchase additional groundwater or surface water licenses to volumetrically offset the impact on the groundwater system.
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Bulga Coal Plan Key Element Trigger Response Water monitoring results are See Section 10.3 BCC to investigate the exceedance and as much as is practical identify the cause, potential remediation and or preventatives measures. outside the maximum reported groundwater level or quality BCC to determine if harm to the environment has occurred as a result of BCC activity and if so report to the EPA as required under the conditions of the EPL. criteria
In the event that the potential impacted were caused by surface flows generated by BCC, BCC could feasible modify the source or route of the surface flow deemed to be creating the impact within the limits of its approvals.
In the event that the potential impacts were caused by underground mining activities a feasible option for mitigating the impact would be the installation of a grout curtain.
BCC to report results of the investigation to senior management, DoPE, DPI and DOE and include in the Annual Review. Seepage from emplacement See Section BCC to investigate the seepage likely cause and identify if any remediation or preventative measures are required. and spoil areas 10.42 Potential feasible remediation and or preventative measures could include the installation of effective seepage recovery system and or minimizing the inflow into the spoil by improving drainage and or vegetative cover.
BCC to report results of the investigation to senior management and include in the Annual Review.
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11.3 Unforeseen Impacts
In the event of unforeseen impacts associated with groundwater, the following protocol will be implemented: conduct a preliminary review of the nature of the impact, including: > any relevant monitoring data; and > current mine activities and land use practices; commission of an investigation by an appropriate qualified expert into the unforeseen impact to confirm cause and effect and consider relevant options for amelioration of impact(s) as appropriate; prepare an action plan in consultation with the appropriate regulatory agency; mitigate causal factors where possible; and implement additional monitoring as necessary to measure the effectiveness of the controls implemented. The outcomes of this protocol will be reported in the AR. The implementation of any mitigation measures will be undertaken in consultation with DP&E, DPI Water and OEH and will be reported in the AR.
12. DECOMMISSIONING STRATEGIES
Decommissioning of water management structures was conceptually discussed in the BOP EIS and will be detailed in the closure and decommissioning MOP that will be submitted prior to mine closure. Prior to closure, each mine water management structure will be assessed in regards to its post mining land use and its potential value. If the assessment concludes that the water management structure is of no further value it will be rehabilitated. After mining is complete the open cut final void will trap and accumulate some surface water. However, final contouring of the surrounding rehabilitation areas will aim to: minimise the catchment area of the final voids and maximise the catchment redirected to natural drainages; control runoff flow rates, velocity and potential for erosion; facilitate revegetation; and create a visually aesthetic final landform. While the final void will remain as a water body in the final landform, it is expected to act as a contained (hydraulic sink) system for the foreseeable future (MER, 2013). A final void management plan will be developed for inclusion in future revisions of this management plan, prior to closure.
13. REPORTING
Monitoring and water balance results will be reported according to the requirements in the relevant monitoring sections of this management plan. Typically these results are presented in either the Quarterly Environmental Monitoring reports and in the AR. Both reports are available on the Bulga Coal external website. Additionally each discharge event is recorded. An annual report of activity under the HRSTS is forwarded to OEH. Hydrogeological investigations by an independent expert are conducted each year and made available on the Bulga Coal website.
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Bulga Coal Plan
14. REVIEW
This document shall be reviewed, and if necessary revised, within 3 months of the following: The submission of an AR; The submission of an incident report under Section 11; The submission of an independent environmental audit; and Following any modification to the Bulga approvals.
DPI Water will be consulted whenever this document is revised or updated.
15. AUDITS AND INSPECTIONS
Internal and external audits of this document will be carried out as described below. Audits shall be carried out by personnel who have the necessary qualifications and experience to make an objective assessment of the issues. The extent of the audit, although pre- determined may be extended if a potentially serious deviation from this document is detected. Any non-conformances and/or improvement opportunities will have corrective and preventative actions implemented to avoid recurrence. Actions will be recorded in either the BCC work order system or CMO so actions can be tracked. 15.1 Internal Audits
Internal audits of this document will be undertaken every three years or when triggered by a modification to either of the development consents. Improvements from the audit are to be incorporated in the site action database so the actions are assigned to the relevant people and completed. 15.2 External Audits
External audits of this management plan will be undertaken by specialists periodically as determined by the BCC Environmental and Community Manager, or in response to significant environmental incidents for which a systems failure has been determined as a contributor to the incident. An Independent Environmental Audit will be undertaken every three years (or as otherwise required by the DP&E) by an audit team whose appointment has been endorsed by the Secretary of the DP&E. Any actions arising from external audits will be loaded into CMO and assigned to the relevant people for completion.
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16. ACCOUNTABILITIES
Role Accountabilities for this document
BCC Environmental and Implement the WMP. Community Manager Review this plan at least every three years or as otherwise advised by the Secretary of Planning & Infrastructure. The reviews will reflect changes in environmental requirements, technology or operational procedures. Requirements for corrective actions identified during monthly inspections are to be reported and managed to ensure that the corrective actions are implemented in a timely manner. A summary of monitoring, works undertaken and results of surface and sub-surface investigations are to be reported in the AR in accordance with EPL 563.
BOC Operations Manager Provide adequate resources for the implementation of this Plan.
BUO Operations Manager Provide adequate resources for the implementation of this Plan.
17. COMPLAINTS PROCEDURES
If complaints relating to surface water or groundwater are received by BCC, the complaint details are to be circulated and actioned by the responsible party. The procedures and protocols are as follows: Depending upon the nature of the complaint, a revision to the procedures maybe required to avoid similar complaints; Actions required in response to complaints are to be effected in a timely manner. The response to complaints shall be communicated to the complainant by the responsible party via a formal letter; and The Environment and Community Manager is to maintain a register of all of the complaints, actions and responses.
18. TRAINING AND AWARENESS
Personnel and contractor new starter training and awareness programs, which include subsidence and environmental components, are undertaken within induction programs outlined within the site Environmental Management System. Records are to be maintained for personnel that have undertaken additional training in pipeline and water management on site.
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Bulga Coal Plan
19. REFERENCES
Australian and New Zealand guidelines for fresh and marine water quality (ANZECC) (2000), “Vol. 1, The guidelines/ Australian and New Zealand Environment and Conservation Council, Agriculture and Resource Management Council of Australia and New Zealand”. David, K (2014), “Groundwater Management Plan for Bulga Optimisation Project (DRAFT) (Report KD2014/3)”. Glencore (2013). Internal Standard “XCN SD ANN 0077 Erosion and Sediment Control Management”. Glencore, Bulga Coal (2014). “Construction Soil & Water Management Plan (XC41200113509)”. GSSE (2010), “Analysis of the Background Water Quality, Bulga Coal Operations”. Mackie Environmental Research (MER) (2013). “Bulga Coal Management Assessment of Groundwater Related Impacts Arising from the Proposed Bulga Optimisation Project– April 2013”. Parsons Brinckerhoff (2014). “Functional Description – Water Management, Bulga Optimisation Project”. RPS Aquaterra (2012). “Review of groundwater trigger levels (Ref: S26K/120a)”. Umwelt (Australia) Pty Limited (2013). “Bulga Optimisation Project, Environmental Impact Statement, Volume 5, Surface Water Assessment”. Umwelt (Australia) Pty Limited (2013). “Bulga Optimisation Project, Response to Submissions and Revised and Amended Project Application Assessment Report”. Umwelt (Australia) Pty Limited (2013). “Bulga Optimisation Project, Appendix 5, Revised Project Surface Water Assessment”. Xstrata Coal, Bulga Coal (2011). “Bulga Coal Landscape Management Plan”. Xstrata Coal, Bulga Coal (2012). “Erosion and Sediment Control Plan (BUL SD PLN 0023)”. Xstrata Coal, Bulga Coal (2013). “Site Water Management Plan (BUL SD PLN 0052)”.
20. CONTROL AND REVISION HISTORY
20.1 Document information
Property Value
Approved by Ralph Northey
Document Owner BCC Environment & Community Manager
Effective Date 28/06/2016
Keywords Site, Water, Management, Plan
For a complete list of document properties, select View Properties from the document’s context menu on the intranet.
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Bulga Coal Plan
20.2 Revisions
Version Date reviewed Review team (consultation) Nature of the amendment
1 22/02/2017 Ralph Northey EPBC2012/6637 version of WMP
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