WATER MANAGEMENT PLAN (WMP)

Transcription

1 Established 1907 WATER MANAGEMENT PLAN (WMP) APPROVED BY MSC DATE: OCTOBER 2018 Version Date Section Modified 1 February 2005 All 2 December 2010 All Reason for Modification Original Management Plan 5 Yearly Review 3 June 2011 All MIA Modification 4 December 2015 All 5 March 2018 All 6 October 2018 S5.2, S5.3 5 Yearly Review Update following modification for Continuation Project Update to monitoring program and trigger levels Review Team MCC Technical Services Department Carbon Based Environmental MCC Technical Services Department Carbon Based Environmental MCC Technical Services Department Carbon Based Environmental MCC Environmental, Technical Services and Production Departments MCC Environmental, Technical Services and Production Departments MCC Environmental Department Approved by General Manager: Date:

2 TABLE OF CONTENTS 1.0 INTRODUCTION SCOPE OBJECTIVES STATUTORY REQUIREMENTS SITE WATER BALANCE WATER INPUTS AND OUTPUTS WATER USAGE WATER MANAGEMENT STRATEGY OFFSITE TRANSFERS AND DISCHARGES FLOW MONITORING MINIMISING WATER USE ON SITE SURFACE WATER MANAGEMENT SURFACE WATER CHARACTERISATION AND MANAGEMENT Clean Water Diversion Systems Erosion and Sediment Controls Mine Water Contaminated Waters and Wastewater DESIGN OBJECTIVES Final Voids Coal Reject Materials Rehabilitated Areas BASELINE WATER QUALITY DATA SURFACE WATER MONITORING PROGRAM SURFACE WATER TRIGGER VALUES Australian and New Zealand Environment and Conservation Council Guidelines for Fresh and Marine Water Quality Water Quality Trigger Values GROUNDWATER MANAGEMENT GROUNDWATER CHARACTERISATION Background Water Quality on Private Bores Groundwater Dependant Ecosystems GROUNDWATER MONITORING PROGRAM GROUNDWATER TRIGGER VALUES Groundwater Level Groundwater Inflow Groundwater Quality Trigger Values GROUNDWATER MODEL VALIDATION TRIGGER ACTION RESPONSE PLAN COMPLAINT MANAGEMENT INCIDENT REPORTING Version 6 October 2018 Page i

3 9.0 EXTERNAL REPORTING ANNUAL ENVIRONMENTAL MANAGEMENT REPORT REVIEW OF MANAGEMENT PLAN RESPONSIBILITIES LIST OF TABLES Table 1: Groundwater Extraction... 2 Table 2: Statutory Requirements... 3 Table 3: Typical Water Usage During Mining Table 4: Surface Water Monitoring Program Table 5: Trigger Values for Muscle Creek Water Quality Table 6: Groundwater Monitoring Program Table 7: Groundwater Level Trigger Values Table 8: Groundwater Quality Trigger Values Table 9: Management Plan Responsibilities LIST OF FIGURES Figure 1: Conceptual Final Landform Drainage Figure 2: Water Monitoring Locations Figure 3: Trigger Action Response Plan for Water Quality Figure 4: Trigger Action Response Plan for Groundwater Level Version 6 October 2018 Page ii

4 1.0 INTRODUCTION Muswellbrook Coal Company Limited (MCC) operates the Muswellbrook Open Cut Coal Mine, located approximately 3 kilometres (km) to the north east of Muswellbrook in the Hunter Valley of New South Wales (Plan 1A). MCC is a wholly owned subsidiary of Idemitsu Australia Resources Pty Limited (IAR). IAR has been operating in Australia since 1978 and is an Australian subsidiary of Japanese company Idemitsu Kosan Company Limited. On September 1, 2003, Development Consent for DA 205/2002 was granted by Muswellbrook Shire Council (MSC) to extend the former MCC No.1 Open Cut. The No.1 Open Cut Extension commenced operations in March 2005 and has a capacity to produce up to 2,000,000 tonnes coal per annum. This approval has subsequently been modified on several occasions with the latest modification granted in 2016 to allow mining in an area known as the Continuation Project and to extend the life of the mining operations to Rehabilitation activities will continue past this date. 1.1 SCOPE The Development Consent requires the preparation, approval and implementation of an Environmental Management Strategy (EMS) and subordinate Environmental Management Plans (EMP). One of these EMPs is the (WMP). This WMP also addresses environmental protection licence conditions and water licence conditions that relate to water management at MCC. Whilst this plan specifically addresses issues related to water management on site, it should be read in conjunction with other EMP s. This WMP has been prepared in consultation with Department of Primary Industries Water (DPI Water) to the satisfaction of MSC (see Appendix 1 for copies of correspondence). 1.2 OBJECTIVES The primary objective of the WMP is to enable the effective management of on site waters to minimise the impact of mining operations on surface and groundwater resources both on and adjacent to the mine site. The WMP will achieve this objective through the implementation of the following strategies: Meeting the water supply needs of the project; Separating clean water runoff produced by undisturbed catchments from dirty (sediment laden) and contaminated runoff from disturbed catchments; Using appropriate sedimentation controls for dirty water; Where possible, recycling and reusing dirty and contaminated mine water for dust suppression and wash down activities; Allowing clean water to flow through the catchment and using clean water for firefighting supplies (firefighting system uses raw mine water) and sensitive equipment where required and allowed by harvestable rights; Where possible, and where mine safety permits, using disused open cuts and underground mines as mine water storages; Version 6 October 2018 Page 1

5 Nil discharge of saline mine water by containing all saline mine water on site and minimising the risk of accidental off site discharge; and Monitoring surface water and groundwater to determine significant impacts to water quality or beneficial use, and undertaking trigger action responses where required. 2.0 STATUTORY REQUIREMENTS Generally, the WMP considers the principles, regulations and guidelines contained in: Water Management Act, Water Act, Protection of the Environment Operations Act, Approved Methods for the Sampling and Analysis of Water Pollutants in NSW (EPA 2004). Australian Standards for water monitoring: AS5667.1:1998 (Guidance on the Design of Sampling Programs, Sampling Techniques and the Preservation and Handling of Samples), AS5667.4:1998 (Guidance on the Sampling from Lakes, Natural and Man Made), AS5667.6:1998 (Guidance on the Sampling of Rivers and Streams), AS :1998 (Guidance on the Sampling of Groundwaters). MCC holds four licences to extract ground water. These licences have been issued in accordance with the Water Act 1912 and Water Management Act The extraction entitlements are shown Table 1. The volume of groundwater extracted from the authorised works shall not exceed the extraction entitlement in a 12 month period commencing 1 July. Legislation Water Management Act Water Act Water Act Water Management Act Table 1: Groundwater Extraction Licence No. 20WA (borehole RDH529) 20BL (No.1 O/C Void) 20BL (No.2 O/C Void) 20WA (borehole RDH607) Extraction Entitlement (ML per Annum Limit) 1,000 2,000 (combined) 3,000 The water related approval and licence conditions are shown in Table 2 along with information on where they are addressed in this plan. Version 6 October 2018 Page 2

6 Table 2: Statutory Requirements Approval/ Licence Condition Condition No. Development Consent 25 The Applicant must prepare a for the development to the satisfaction of Council, and carry out the development in accordance with this plan. The plan must be prepared in consultation with DPI Water and submitted to Council for approval and include: 25 (a) A Site Water Balance that: a) Includes details of: i. Sources and security of water supply, including contingency planning for future reporting periods ii. Water use and management on site; iii. Any offsite water transfers and discharges; iv. Reporting procedures, including the preparation of a site water balance for each AEMR reporting year; and b) Investigates and implements all reasonable and feasible measures to minimise water use on site; 25 (b) Surface that includes: a) Detailed baseline (2016) data on surface water quality in the watercourses that could potentially be affected by the development 25 (b) b) a description of the water management system on site, including the: i. Clean water diversion systems; ii. Erosion and sediment controls (mine water system); and iii. Mine water management systems including water infusion for Spontaneous Combustion. 25 (b) c) plans, including design objectives and performance criteria, for: i. design and management of final voids; ii. design and management for the emplacement of coal reject materials; iii. reinstatement of drainage lines on the rehabilitated areas of the site; and iv. control of any potential water pollution from the rehabilitated areas of the site Section This plan , 4.1.2, Version 6 October 2018 Page 3

7 Approval/ Licence Condition Condition No. 25 (b) d) performance criteria for the following, including trigger levels for investigating any potential adverse impacts associated with the development: i. surface water quality of Muscle Creek and Sandy Creek catchments; and 25 (b) e) a program to monitor and report on: i. the effectiveness of the mine water management system; and ii. surface water quality, in Muscle Creeks and Sandy Creeks, potentially affected by the development; 25 (b) f) a plan to respond to any exceedances of the performance criteria, and mitigate and/or offset any adverse surface water impacts of the development; and 25 (c) Groundwater Management Plan, which includes: a) baseline data on groundwater levels, and quality, of privately owned registered groundwater bores within 2.5km of the development, that could be affected by the development; 25 (c) b) groundwater assessment criteria, including trigger levels for investigating any potentially adverse groundwater impacts; 25 (c) c) a program to monitor and report on: i. ground water inflows to the open cut pits; ii. the impacts of the development on: 1. regional and local (including alluvial) aquifers; 2. groundwater supply of privately registered groundwater bores; iii. iv. a plan to respond to any exceedances of the groundwater assessment criteria; and a program to validate the groundwater model for the development, including an independent review of the model with every Independent Environmental Audit, and compare the monitoring results with modelled predictions. Environmental Protection Licence EPL656 L1.1 Except as may be expressly provided in any other condition of this licence, the licensee must comply with section 120 of the POEO Act (1997). Water Approval 20WA Section , Appendix Noted Version 6 October 2018 Page 4

8 Approval/ Licence Condition Condition No. 2 The licence holder must develop and implement a methodology to estimate the annual volume of all groundwater inflow (water budget), approved by the Office of Water. Water budgets must be set and approved one month prior to the beginning of each water year to enable implementation. 5 The license holder must provide the Office of Water with a management plan, within six months of issuing the licence, to identify measures to be used to minimise ongoing seepage of alluvial groundwater to the mine works and for restoring the mine works above the final water level for when the pits are no longer being used, to be approved by the Office of Water. 7 The licence holder must develop and implement a Groundwater Monitoring and Contingency Plan, with its reporting schedule, and approved by the Office of Water. The Groundwater Monitoring and Contingency Plan is to be prepared and submitted to the Office of Water within six months of issuing the licence using the template provided by the Office of Water. 8 The licence holder must provide the Office of Water with an annual compliance report, to report on the results of the Groundwater Monitoring and Contingency Plan, within (3) three months of the end of the water year being reported on. The Annual Compliance Report must: a) assess compliance with the licence, including the groundwater monitoring; b) provide a summary of new bores or pits constructed during that year; c) provide a statistical summary for the monitoring data collated for each bore for the last water year. 9 An extraction measurement device must be installed and maintained on each extraction device (pump) used for extraction of water under this licence, and such devices must be of a type and standard, and must be maintained in a manner, which is acceptable to the Office of Water. 12 The volume of groundwater extracted from the works authorised by this licence, shall not exceed 1000 megalitres (ML) in any 12 month period commencing 1st July. (This is referred to as the "Groundwater Only Allocation") Water Licence 20BL The licence holder must develop and implement a methodology to estimate the annual volume of all groundwater inflow (water budget), approved by the Office of Water. Water budgets must be set and approved one month prior to the beginning of each water year to enable implementation. Section 3.1 N/A previous correspondence has been provided to DPI Water This plan Version 6 October 2018 Page 5

9 Approval/ Licence Condition Condition No. 5 Within 3 months of being issued the licence, the license holder must provide the Office of Water with a management plan that identifies measures for restoring the mine works above the final water table when they are no longer being used. 6 The licence holder must develop and implement a Groundwater Monitoring and Contingency Plan, with its reporting schedule, and approved by the Office of Water. The Groundwater Monitoring and Contingency Plan is to be prepared and submitted to the Office of Water within six months of issuing the licence using the template provided by the Office of Water. 7 As part of the annual reporting required under the Development Consent, the licence holder must: (I) assess compliance with the terms and conditions of the licence; (II) provide a summary of new bores or pits constructed during that year; (III) provide key statistics for the monitoring data collated for each bore for the previous water year; (IV) summarise events that impacted on groundwater during the previous water year, including actions taken to remedy the situation and relevant extra monitoring results; and (V) include any recommendations or measures to be taken for improvements for the new water year. 8 An extraction measurement device must be installed and maintained on each extraction device (pump) used for extraction of water under this licence, and such devices must be of a type and standard, and must be maintained in a manner, which is acceptable to the Office of Water. Section N/A previous correspondence has been provided to DPI Water This plan Version 6 October 2018 Page 6

10 Approval/ Licence Condition Condition No. 9 As part of the independent environmental auditing required under the Development Consent, the licence holder must ensure that the audit: (I) seeks input from the Office of Water; (II) assess compliance with the terms and conditions of this licence; (III) assess compliance with the and any sub plans under the Development Consent; (IV) review reported impacts of the extractions on any aquifers, groundwater dependent eco systems and any streams in the area; (V) assess the methodology used to report the impacts in Condition 7 (IV); (VI) make comparisons between reported and predicted impacts (modelled results); and (VII) provide recommendations regarding any works that should be performed or additional obligations that should be imposed in order to rectify any impacts on groundwater or any connected water dependent assets. 10 The volume of groundwater extracted from the works authorised by this license and license(s) 20BL shall not exceed 2000 megalitres in any 12 month period commencing 1st July. Water Licence 20BL The licence holder must develop and implement a methodology to estimate the annual volume of all groundwater inflow (water budget), including a methodology to determine alluvial water inflow, approved by the Office of Water. Water budgets must be set and approved one month prior to the beginning of each water year to enable implementation. 5 Within 3 months of being issued the licence, the license holder must provide the Office of Water with a management plan that identifies measures for restoring the mine works above the final water table when they are no longer being used. 6 The licence holder must develop and implement a Groundwater Monitoring and Contingency Plan, with its reporting schedule, and approved by the Office of Water. The Groundwater Monitoring and Contingency Plan is to be prepared and submitted to the Office of Water within six months of issuing the licence using the template provided by the Office of Water. Section Environmental Management Strategy N/A previous correspondence has been provided to DPI Water This plan Version 6 October 2018 Page 7

11 Approval/ Licence Condition Condition No. 7 As part of the annual reporting required under the Development Consent, the licence holder must: (I) assess compliance with the terms and conditions of the licence; (II) provide a summary of new bores or pits constructed during that year; (III) provide key statistics for the monitoring data collated for each bore for the previous water year; (IV) summarise events that impacted on groundwater during the previous water year, including actions taken to remedy the situation and relevant extra monitoring results; and (V) include any recommendations or measures to be taken for improvements for the new water year. 8 An extraction measurement device must be installed and maintained on each extraction device (pump) used for extraction of water under this licence, and such devices must be of a type and standard, and must be maintained in a manner, which is acceptable to the Office of Water. 9 As part of the independent environmental auditing required under the Development Consent, the licence holder must ensure that the audit: (I) seeks input from the Office of Water; (II) assess compliance with the terms and conditions of this licence; (III) assess compliance with the and any sub plans under the Development Consent; (IV) review reported impacts of the extractions on any aquifers, groundwater dependent eco systems and any streams in the area; (V) assess the methodology used to report the impacts in Condition 7 (IV); (VI) make comparisons between reported and predicted impacts (modelled results); and (VII) provide recommendations regarding any works that should be performed or additional obligations that should be imposed in order to rectify any impacts on groundwater or any connected water dependent assets. 10 The volume of groundwater extracted from the works authorised by this license and license(s) 20BL shall not exceed 2000 megalitres in any 12 month period commencing 1st July. Water Approval 20WA Section Environmental Management Strategy 2.0 Version 6 October 2018 Page 8

12 Approval/ Licence Condition Condition No. 2 The licence holder must develop and implement a methodology to estimate the annual volume of all groundwater inflow (water budget), approved by the Office of Water. Water budgets must be set and approved one month prior to the beginning of each water year to enable implementation. 5 Within 3 months of being issued the licence, the license holder must provide the Office of Water with a management plan that identifies measures for restoring the mine works above the final water table when they are no longer being used. 6 The licence holder must develop and implement a Groundwater Monitoring and Contingency Plan, with its reporting schedule, and approved by the Office of Water. The Groundwater Monitoring and Contingency Plan is to be prepared and submitted to the Office of Water within six months of issuing the licence using the template provided by the Office of Water. 7 As part of the annual reporting required under the Development Consent, the licence holder must: (I) assess compliance with the terms and conditions of the licence; (II) provide a summary of new bores or pits constructed during that year; (III) provide key statistics for the monitoring data collated for each bore for the previous water year; (IV) summarise events that impacted on groundwater during the previous water year, including actions taken to remedy the situation and relevant extra monitoring results; and (V) include any recommendations or measures to be taken for improvements for the new water year. 8 An extraction measurement device must be installed and maintained on each extraction device (pump) used for extraction of water under this licence, and such devices must be of a type and standard, and must be maintained in a manner, which is acceptable to the Office of Water. Section 3.1 N/A previous correspondence has been provided to DPI Water This plan Version 6 October 2018 Page 9

13 Approval/ Licence Condition Condition No. 9 As part of the independent environmental auditing required under the Development Consent, the licence holder must ensure that the audit: (I) seeks input from the Office of Water; (II) assess compliance with the terms and conditions of this licence; (III) assess compliance with the and any sub plans under the Development Consent; (IV) review reported impacts of the extractions on any aquifers, groundwater dependent eco systems and any streams in the area; (V) assess the methodology used to report the impacts in Condition 7 (IV); (VI) make comparisons between reported and predicted impacts (modelled results); and (VII) provide recommendations regarding any works that should be performed or additional obligations that should be imposed in order to rectify any impacts on groundwater or any connected water dependent assets. 10 The volume of groundwater extracted from the works authorised by this license shall not exceed 3000 megalitres in any 12 month period commencing 1st July. Section Environmental Management Strategy 2.0 Version 6 October 2018 Page 10

14 3.0 SITE WATER BALANCE 3.1 WATER INPUTS AND OUTPUTS The inputs of water for the mine water balance are: Groundwater inflows to the operations determined from analytical modelling; Surface water runoff into site dams; Pumping water from the underground bores in accordance with water licence conditions; Entrainment in coal; and Supply of potable water from MSC in accordance with commercial agreement. The outputs of water for the mine water balance are: Water cart usage for dust suppression; Water infusion for spontaneous combustion management; Evaporation from dams; and Entrainment in coal leaving site. MCC has access to a significant resource in groundwater via the two boreholes located immediately to the north of the operation, which is adequate for the current mining operations. As the production output of the operation will not increase and the mine has a relatively short life, these water sources will be adequate for the rest of the mine life and there is no requirement to identify any contingency measures for the operation. 3.2 WATER USAGE Numerous groundwater assessments involving analytical modelling have been undertaken at MCC. A water balance model has been developed by comparison of: pumped volumes, analytical modelling of groundwater inflows, estimated groundwater through flows, surface water inflows and evaporation rates. Typical water usage in an average rainfall year (mean annual rainfall mm/year) is shown in Table 3. Version 6 October 2018 Page 11

15 Table 3: Typical Water Usage During Mining Source Volume (ML/year) Inputs Groundwater Inflows 100 Surface Water Runoff 175 Average Groundwater Abstraction 2,000 Entrainment in Coal 150 Potable Water 5 Total 2,430 Outputs Dust Suppression 450 Water Infusion spontaneous combustion management 1,400 Dam Evaporation 130 Entrainment in Coal 120 Septic Pump Out 1 Total 2,101 Total water balance inputs and outputs vary depending on rainfall variability. During wet periods, surface water runoff and retention increases, resulting in a decrease in dust suppression demand. During periods of water stress, groundwater abstraction volumes increase, meeting the deficit of surface water demand. The yearly site water balance will be reported in the Annual Environmental Management Report. 3.3 WATER MANAGEMENT STRATEGY The water management system at MCC is a closed system. MCC do not source mine water from external third parties or discharge water off site. The groundwater extraction is from old underground workings and there is adequate on site storage for the water. More details on the water management strategy can be found in Section OFFSITE TRANSFERS AND DISCHARGES There are no offsite transfers or discharges of water from MCC. 3.5 FLOW MONITORING Flow monitoring is an integral part of monitoring the site water requirements and allows the calculation of accurate water balances. The following monitoring will allow the assessment of water make and usage, and will facilitate the planning for new water storages. Flow meters have been installed on the following pipelines: Pipeline from No. 2 Open Cut to Dam No. 1; Pipeline from Borehole Pump 1 and Borehole Pump 2 to Dam No. 2; Pipeline from Dam No. 2 to Workshop Dam; Pipeline that supplies water for dust suppression; and Pipeline from Final Settling Pond to Workshop Dam. Version 6 October 2018 Page 12

16 Each flow meter is read and recorded on a regular basis (minimum 6 monthly). The water levels in Dam No. 2, OC Voids and the Final Settling Pond will be recorded on a regular basis (minimum quarterly). The levels will be recorded by survey RL or appropriate measuring boards. 3.6 MINIMISING WATER USE ON SITE MCC has reviewed the current water use on site and have not identified any reasonable or feasible options to reducing the water usage on site. MCC have water licences in place to extract up to 4,000ML/year from two boreholes and as shown in Table 3 the typical groundwater extraction is 2,000ML/year from these two boreholes, which indicates that MCC are minimising the water usage on site. MCC are a self sufficient site with regards to water management and have adequate water available for the operation. MCC will continue to review current management practices to identify any reasonable or feasible options to reduce the water usage on site. 4.0 SURFACE WATER MANAGEMENT 4.1 SURFACE WATER CHARACTERISATION AND MANAGEMENT The two main catchments in the vicinity of the site are associated with Muscle and Sandy Creeks, both of which discharge into the Hunter River. Drainage from the site is to the north to Sandy Creek, south to Muscle Creek, and west to the Hunter River. The site is well beyond the boundary of the alluvial floodplain and the 100 year flood limit of the Hunter River. The water management system at MCC principally consists of: The use of Open Cut 2 as storage, which will gradually reduce as overburden is emplaced in Open Cut 2, reducing the amount of water entering the mine water system; The use of the underground workings as water storage; and The storage of water in the mine water dams (Dams 1/2 and Final Settling Dams) for use as dust suppression. In the event of a significant rainfall event, the open cuts have significant available storage capacity to contain runoff with pumping infrastructure in place to transfer water around the site as required. As the mining progresses to the north, the catchment of Open Cut 1 would increase while the catchment of Dams 1 and 2 would decrease. This will reduce the risk of overflow from these dams. No additional works would occur outside of the catchments of Open Cut 1, Open Cut 2 and Dams 1 and 2. As future mining will be fully contained within the existing internally draining catchments, there will be no impact to local watercourses from the mining operations. Version 6 October 2018 Page 13

17 4.1.1 Clean Water Diversion Systems Clean water is classified as storm water which runs off from undisturbed catchments. Where practicable, clean water will be kept separate from dirty water, mine water or contaminated water streams. Clean water diversions will be designed in accordance with the principles of the Soils and Construction Managing Urban Stormwater (Blue Book, Landcom 2004). The clean water diversions are shown in Figure Erosion and Sediment Controls The key considerations for erosion and sediment control at MCC include: restricting the extent of disturbance to the minimum that is practical and in accordance with the Mining Operations Plan/Rehabilitation Plan; progressive rehabilitation of disturbed land, where possible, and the construction of drainage controls to improve the stability of rehabilitated land; protection of natural drainage lines and watercourses by the construction of erosion control devices such as diversion banks and channels and sediment retention dams as necessary; restriction of access to rehabilitated areas; management of erosion and sediment control of affected surface watercourses/ water bodies, including creek lines within or adjacent to the development consent boundary; regular inspection of dams to monitor their efficiency and any required maintenance; and inspection and maintenance, if required, of sediment and erosion controls including dams and drainage lines following storm events. A conceptual final landform drainage plan, incorporating appropriate erosion and sediment controls is shown on Figure Mine Water Mine water is water with elevated salinity and suspended sediment, generated from disturbed catchments where coal is mined or handled such as the open cuts, the underground mines, coal stockpiles, the CHPP, workshop and haul roads. The strategy for the management of saline water is as follows: Saline water will be kept separate from clean water runoff and will be collected and re used for process water in preference to other water sources; Saline water will be used in the water infusion process to assist with spontaneous combustion management; and Saline water is not planned to be discharged from the site but any future requirement will be in accordance with the requirements of the Hunter River Salinity Trading Scheme and the Environmental Protection Licence Contaminated Waters and Wastewater Contaminated waters from the workshop and hardstand areas that may contain oils and greases are diverted to a three staged silt trap and oil/water separator. Sewage effluent Version 6 October 2018 Page 14

18 is stored in septic tanks and pumped into road tankers and taken offsite. 4.2 DESIGN OBJECTIVES Final Voids In accordance with the Blue Book, contour banks would be required at a spacing of m (depending upon the slope gradient) within the voids to safely convey runoff down the slopes. Subsequently, drop structures would also be required to convey concentrated flow captured by these contour banks into the base of the final voids. Without such drainage control structures, it is expected that rilling and gullying would occur on the landform which would destabilise the soils and reduce the overall effectiveness of rehabilitation. A conceptual final landform drainage plan, incorporating appropriate erosion and sediment controls is shown on Figure Coal Reject Materials All coal reject material is dumped in the active dumping areas on site. The processing of this material removes most of the water from this material and it can be handled as solid material. Any water coming into contact with this material will be managed in the mine water system Rehabilitated Areas Based on the principles of the Blue Book, disturbed landforms require benching in the form of contour drains and drop structures to safely convey runoff and reduce the potential for erosion (rilling and gullying) to develop. The final landform would have maximum slope gradients of up to 14 degrees within the final shaped voids with slope lengths of between m from the void crest to the base of the void. It is noted that the lower portion of the voids would fill with water over time, and therefore the slope lengths would be reduced to a maximum length of approximately 600m. A highwall will be left in Open Cut 2 with slopes up to 65 degrees. Water from areas undergoing active rehabilitation will be considered as dirty water and managed in the erosion and sediment control structures on site. Once successful rehabilitation has been achieved, the various sediment dams at MCC will no longer be considered as pollution control dams under the Water Management Act and consideration will need to be given to the Maximum Harvestable Rights Design Capacity (MHRDC). Where the capacity of the dams exceeds 10% of the harvestable rights of the contributing catchment, additional works may be required to reduce the capacity of dams to provide environmental flows and meet the requirements of the MHRDC or divert water away from these dams. Alternatively, the dams may require licensing. How this issue is to be managed will be determined during closure of the operation. A conceptual final landform drainage plan, incorporating appropriate erosion and sediment controls is shown on Figure 1. Version 6 October 2018 Page 15

19 Figure 1: Conceptual Final Landform Drainage Version 6 October 2018 Page 16

20 4.3 BASELINE WATER QUALITY DATA A review of the water quality in Muscle Creek has been undertaken to develop detailed baseline data, which has been used to calculate trigger levels and performance criteria for Muscle Creek. The baseline data has been calculated since the sites were first sampled in August 2011 through to December The detailed baseline data is shown in Appendix 2. There is more information on the trigger levels and the performance criteria developed from this baseline data in Section SURFACE WATER MONITORING PROGRAM The locations of the current surface water monitoring program are shown in Figure 2. The frequency of monitoring and the analysis required are summarised in Table 4. Table 4: Surface Water Monitoring Program Site Monitoring Frequency Analysis No 1 Void Monthly ph, EC, TSS Annually Comprehensive No 2 Void Monthly ph, EC, TSS Annually Comprehensive Dam 1/2 Monthly ph, EC, TSS Annually Comprehensive MCC7 Muscle Creek Monthly ph, EC, TSS, flow Upstream Annually Comprehensive MCC8 Muscle Creek Monthly ph, EC, TSS, flow Downstream Annually Comprehensive MCC9 Brickworks Dam Quarterly ph, EC, TSS Annually Comprehensive MCC12 Final Settling Monthly ph, EC, TSS Dam Annually Comprehensive MCC23 E. Emplacement Quarterly ph, EC, TSS Dam South Annually Comprehensive MCC24 East Haul Road Quarterly ph, EC, TSS Dam Annually Comprehensive MCC25 E. Emplacement Quarterly ph, EC, TSS Dam North Annually Comprehensive MCC26 Blues Crusher Quarterly ph, EC, TSS Dam Annually Comprehensive MCC27 Dam 3 Quarterly ph, EC, TSS Weighbridge dam (not shown on Figure 2) Annually Only during observed overflow Comprehensive ph, EC, TSS Version 6 October 2018 Page 17

21 Site Monitoring Frequency Analysis Comprehensive analysis monitors for the following: ph, electrical conductivity (EC), total suspended solids (TSS), hardness, calcium, magnesium, sodium, potassium, sulphate, chloride, fluoride, carbonate, bicarbonate, nitrate, oil and grease, ammonia, dissolved iron, total iron, manganese, arsenic, barium, boron, cadmium, chromium, copper, nickel, lead, zinc, mercury, selenium, total petroleum hydrocarbons, polycyclic aromatic hydrocarbons Annual analysis is undertaken in March each year Quarterly analysis is undertaken in June, September and December each year All sampling is conducted in accordance with relevant Australian Standards for water monitoring: AS5667.1:1998 (Guidance on the Design of Sampling Programs, Sampling Techniques and the Preservation and Handling of Samples), AS5667.4:1998 (Guidance on the Sampling from Lakes, Natural and Man Made), and AS5667.6:1998 (Guidance on the Sampling of Rivers and Streams). 4.5 SURFACE WATER TRIGGER VALUES Australian and New Zealand Environment and Conservation Council Guidelines for Fresh and Marine Water Quality The Australian and New Zealand Environment and Conservation Council Guidelines for Fresh and Marine Water Quality (ANZECC and ARMCANZ 2000) (Water Quality Guideline) aim to protect and manage the environment supported by a water resource whilst maintaining economic and social development. The Water Quality Guideline provide guidance on site specific assessment criteria and general numerical values to assess water quality. The Water Quality Guideline recommend that wherever possible, site specific data is used to define trigger values for physical and chemical factors which can adversely impact the environment. This is a much more rigorous and accurate approach to assess potential project related impacts rather than application of the generic water quality values. If suitable site specific trigger values cannot be developed, the default (acceptable limit) values defined by the Water Quality Guideline for upland rivers in slightly disturbed ecosystems in south east Australia are adopted. Version 6 October 2018 Page 18

22 Figure 2: Water Monitoring Locations Version 6 October 2018 Page 19

23 4.5.2 Water Quality Trigger Values The approach recommended by the Water Quality Guideline for developing site specific trigger values for slightly to moderately disturbed ecosystems is to formulate trigger values based on the 80th percentile (and the 20 th percentile values where applicable) of the site specific monitoring data. Using these percentiles removes outliers that are outside of the normal range (defined as 20 80% of values). This approach recommends the reference data set should be calculated from a minimum of two years of monthly data (i.e. 24 data points). There is sufficient baseline data from Muscle Creek to calculate trigger values in accordance with the Water Quality Guideline for ph, EC and TSS (see Appendix 2 for historic results). Where baseline results were below the laboratory limit of reporting a conservative approach was adopted and the value was halved and included in the calculations for the trigger vales. The trigger values for water quality in Muscle Creek are presented in Table 5. Table 5: Trigger Values for Muscle Creek Water Quality Site ph 20 th /80 th Percentile Trigger Values EC (µs/cm) 80 th Percentile Trigger Values TSS (mg/l) 80 th Percentile Trigger Values SW07 Muscle Creek Upstream , SW08 Muscle Creek Downstream , GROUNDWATER MANAGEMENT 5.1 GROUNDWATER CHARACTERISATION There are two main groundwater systems present at the mine site and within the immediate vicinity of the mine site. These aquifers are the shallow bedrock (regolith) and Permian bedrock (Greta Coal Measures). The characteristics of the shallow bedrock (regolith) are: surficial sandy and silty clayey soils and weathered bedrock; variable permeability and porosity (primary and secondary); variable depth and thickness; temporary perched groundwater during sustained wet periods; and provides a source of recharge to the underlying coal measures, although limited given the very low hydraulic conductivities of deeper strata. The characteristics of the Permian bedrock (Greta Coal Measures) are: negligible intergranular (primary) porosity and permeability; low to moderately permeable coal seams are the prime water bearing strata with typical permeability of c.2m/day at shallow depths to less than 0.01m/day at a depth of 130m; Version 6 October 2018 Page 20

24 groundwater is associated with fracture (secondary) permeability and porosity from discontinuities (fractures, faults, joints and bedding planes); intervening unproductive coal measures are tight with permeability c.2 orders of magnitude lower than that of the coal seams (i.e. 0.01m/day at shallow depths to m/day at 100m depth); and specific storage coefficient (storativity) is estimated to be in the order of c.3 x Apart from the aquifer systems, groundwater is also stored in the old, flooded, underground, and pillar workings of the No. 2 Underground and St Heliers Colliery. The modelled standing water levels in each open cut final void are 196mAHD for Open Cut 1 and 157mAHD in Open Cut 2, which represents a depth of water of 22m and 25m respectively. These levels are below the background standing water level of 210mAHD. Therefore, the final voids are expected to remain a groundwater evaporative sink and will not contribute water to the groundwater system(s). The Open Cut 1 void is estimated to reach equilibrium (196mAHD) within approximately 50 years. The Open Cut 2 void is estimated to reach equilibrium (157mAHD) within approximately 35 years. Based on the final landform, the spill levels for each open cut pit are approximately 210m AHD for Open Cut 1 and 200m AHD for Open Cut 2. This provides approximately 14m freeboard in Open Cut 1 and 43m freeboard in Open Cut 2. This equates to an overall freeboard capacity of approximately 5,320ML in Open Cut 1 void and 14,400ML in Open Cut 2 void, which is more than sufficient to hold rainfall from the calculated catchments for the Probable Maximum Precipitation rainfall event. These results are slightly different to those presented in the Continuation Project SEE due to a review that was undertaken following changes to the surface water management structures on the final landform Background Water Quality on Private Bores A review of publicly available information indicates there are no privately owned groundwater bores within a 2.5km radius from the centre of the open cut operations. The maximum radius of groundwater drawdown impact has been modelled to be approximately 1km. Based on this calculations of the groundwater levels and quality in privately owned registered bores is not required Groundwater Dependant Ecosystems No listed high priority groundwater dependent ecosystems (GDEs) have been identified within the mines surrounds in the applicable water sharing plan (Water Sharing Plan for the Hunter Regulated River and Water Sharing Plan for the Hunter Unregulated and Alluvial Water Sources). Version 6 October 2018 Page 21

25 5.2 GROUNDWATER MONITORING PROGRAM Numerical groundwater flow modelling indicates the estimated radius of groundwater impact is less than 1km, and alluvial aquifers and registered bore users are not predicted to be impacted because of the modification. The groundwater monitoring network in the Sandy Creek area, to the projects north and north west, will comprise the projects monitoring network. The groundwater monitoring network consists of three Sandy Creek alluvial sites (MCC1003, MCC1005 and MCC1006) and three hardrock monitoring sites (MCC1015, MCC1017 and MCC1018), as shown in Figure 2. Monthly monitoring commenced across the groundwater monitoring network in 2004 and has been ongoing at all locations except MCC1017 and MCC1018 where water quality monitoring ceased in MCC has been monitoring groundwater levels and quality from site monitoring bores for a number of years. The location of the groundwater monitoring network is shown on Figure 2. The frequency of monitoring and the analytical suite are summarised in Table 6. Table 6: Groundwater Monitoring Program Site Target formation Monitoring Analysis Frequency RDH607/ Permian hardrock coal Monthly Depth, ph, EC RDH529 measure Annually Comprehensive RDH616 Permian hardrock coal Monthly Depth and interburden near fault RDH617 Permian hardrock coal Monthly Depth and interburden near fault RDH624 Permian hardrock coal Monthly Depth and interburden RDH650 Permian hardrock coal Monthly Depth measure MCC1003 Sandy Creek alluvium Monthly Depth, ph, EC Annually Comprehensive MCC1005 Sandy Creek alluvium Monthly Depth, ph, EC Annually Comprehensive MCC1006 Sandy Creek alluvium Monthly Depth, ph, EC Annually Comprehensive MCC1017 Permian hardrock coal Monthly Depth and interburden MCC1018 Permian hardrock coal and interburden Monthly Depth Version 6 October 2018 Page 22

26 Site Target formation Monitoring Analysis Frequency Comprehensive analysis monitors for the following: solids (TSS), hardness, calcium, magnesium, sodium, potassium, sulphate, chloride, fluoride, carbonate, bicarbonate, nitrate, oil and grease, ammonia, dissolved iron, total iron, manganese, arsenic, barium, boron, cadmium, chromium, copper, nickel, lead, zinc, mercury, selenium, total petroleum hydrocarbons, polycyclic aromatic hydrocarbons Annual analysis is undertaken in March each year All monitoring will be conducted in accordance with the relevant Australian Standards for water monitoring: AS5667.1:1998 (Guidance on the Design of Sampling Programs, Sampling Techniques and the Preservation and Handling of Samples) and AS :1998 (Guidance on the Sampling of Groundwaters). 5.3 GROUNDWATER TRIGGER VALUES Groundwater Level Baseline groundwater level data has been collated and statistically analysed (Appendix 3). The mean baseline average, standard deviation and the 20th percentile average has been calculated with the objective of establishing trigger values. Based on the observed results, groundwater level typically displays a greater range in the shallower alluvial groundwater system when compared with the deeper hardrock groundwater system. The following equation has been used to derive site specific groundwater level trigger values: Threshold = (standard deviation from mean*2)*20% Equation 1 An arbitrary 20% buffer is applied to the natural variability range observed in the available data to account for possible greater variability which could occur during more extreme annual seasons. The groundwater trigger levels are shown in Table 7. Monitoring Location Table 7: Groundwater Level Trigger Values Historical Historical Water Water Level Level Range Range (m)ahd (m)btoc Target Formation Lower Trigger Values (m)btoc Lower Trigger Values (m)ahd MCC1003 Alluvial MCC1005 Alluvial MCC1006 Alluvial MCC1017 Hardrock MCC1018 Hardrock BTOC = below top of casing, AHD = Australian Height Datum Version 6 October 2018 Page 23

27 5.3.2 Groundwater Inflow The Groundwater Assessment for the Continuation Project confirmed that the groundwater inflow into the Open Cut area is approximately 100ML/year. During the groundwater model validation process this value will be confirmed and the water balance updated if required. Pit inflow and groundwater abstraction from bores is reported annually in the Annual Environmental Management Report. MCC has an entitlement to 6,000 ML/year groundwater, with average take totalling approximately 2,100 ML/year (combining groundwater abstraction and pit inflows). Therefore, groundwater is adequately licensed Groundwater Quality Trigger Values The approach recommended by the Water Quality Guideline for developing site specific groundwater quality trigger values is based on the 80 th percentile (and the 20 th percentile values for ph) of the site specific monitoring data (outlined in Section 5.4.2). There is sufficient data from up to 16 years of monitoring to calculate groundwater quality trigger values in accordance with the Water Quality Guideline for ph and EC (Appendix 3 for historical data). The groundwater quality trigger values are presented in Table 8. Table 8: Groundwater Quality Trigger Values Site ph 20 th /80 th Percentile EC (µs/cm) 80 th Percentile Trigger Values Trigger Values MCC ,666 MCC ,584 MCC ,152 µs/cm = microsiemens per centimetre 5.4 GROUNDWATER MODEL VALIDATION Every three years MCC are required to coordinate the completion of an Independent Environmental Audit. As part of this audit process, MCC will coordinate an independent review of the groundwater model and compare the monitoring results with modelled predictions. 6.0 TRIGGER ACTION RESPONSE PLAN The ongoing, monthly water monitoring will be used to identify potential project related impacts on the receiving waters and to inform the appropriate response. All studies completed to date indicate no adverse effects on surface water or groundwater, however a trigger action response plan will be implemented to manage any potential adverse impacts on surface water and groundwater quality, and groundwater levels. Trigger value exceedances will initiate a preliminary investigation and additional water quality sampling if exceedances are related to water quality. Further investigations and Version 6 October 2018 Page 24

28 possible management responses may be required as per Figure 3 and Figure 4. The water quality trigger action response plan (Figure 3) will be activated if exceedances of water quality trigger value criteria for surface water (Table 5) and/or groundwater (Table 8) occurs. A trigger action response plan (Figure 4) will be initiated for groundwater levels and/or groundwater flow if groundwater inflow exceedance (50% of quarterly take) or groundwater level triggers are exceeded (Table 8). It is important to note that data generated from environmental sampling are inherently noisy. The occasional excursion beyond a trigger value may be encountered due to a variety of factors or may indicate a potential project related impact. The method used to calculate trigger values for the project recognises the inherent variability of natural systems by acknowledging natural and sampling induced variation. 7.0 COMPLAINT MANAGEMENT Water related complaints by the community can be directed to the 24 hour toll free telephone Environmental Contact Line More details on the complaints management at MCC are found in the Environmental Management Strategy. 8.0 INCIDENT REPORTING In the event that the trigger response action plan concludes that a water related incident has occurred the incident will be reported to MSC and DPI Water within 24 hours of confirming the incident. Within six days of the incident being confirmed MCC will notify MSC and DPI Water of an incident via a written report that: a) Describes the date, time, and nature of the incident; b) Complies the analytical results relating to the incident; c) Identifies the cause (or likely cause) of the incident; d) Describes what action and additional monitoring has been taken to date; e) Describes the proposed measures and management responses to address the incident and prevent further exceedances; and Includes a statement regarding the potential effects on the receiving environment and the need for further investigation and assessment. Version 6 October 2018 Page 25

29 Water quality trigger value exceeded for three consecutive rounds of monthly monitoring. YES NO Continue with routine monitoring. Assess possible causes or sources for trend/exceedance, including: Phase 1 Investigation review of climate data; if applicable to surface water, sample the Muscle Creek tributary from site if flowing review of projects activities including erosion and sediment control practices; review incidents on site in the preceding three months (eg spills); and assessment of potential impacts of offsite land use practices that might have affected the results. Is the source possibly from activities relating to the project, and is there a risk of adverse or significant effect on receiving environment? YES Conduct unscheduled monitoring round to further verify trend/exceedance as soon as possible and within four weeks of previous monitoring round. NO No further action required. Continue with routine monitoring Is the trend/exceedance further verified? YES NO No further action required. Continue with routine monitoring Phase 2 Investigation Initiate management response to avoid future exceedances (ie sedimentation fences) and report to relevant government agencies (DPI Water and MSC) within six days of confirming the exceedance, including: data compilation of analytical results; assessment of processes that may have contributed to the exceedance (eg review of incidents on site in the preceding three months, major maintenance activities, weather conditions and observations during sampling); details of additional monitoring, if any, required to confirm the significance and the duration of the exceedance; management response to prevent further exceedances; and a statement regarding potential effects on the receiving environment and the need for further investigation and assessment. Assess Phase 2 Investigation. Is further action required? NO YES Phase 3 Investigation Undertake further action in consultation with the relevant government agencies and report to relevant government agencies. Figure 3: Trigger Action Response Plan for Water Quality Version 6 October 2018 Page 26

30 Groundwater level exceeds trigger levels for a three month period. NO Continue with routine monitoring. YES Assess possible causes or sources for drawdown / ingress, including: climate conditions and/or landholder activity review of projects activities and dewatering in the area; and review of non project activities in the area that could impact groundwater levels. Phase 1 Investigation Is the drawdown exclusively from activities relating to the project, and is there a risk of adverse or significant effect on the environment? NO No further action required. Continue with routine monitoring. YES Phase 2 Investigation Initiate management response and report to relevant government agencies (DPI Water and MSC) within six days of confirming the exceedance, including : data compilation of analytical results; assessment of processes that may have contributed to the exceedance (eg review of dewatering activities, climate conditions and observations during sampling); management options to avoid future impacts; details of additional monitoring, if required to confirm the significance and the duration of the impact; and a statement regarding potential effects on the receiving environment and the need for further investigation and assessment. YES Report to relevant government agencies (DPI Water) within six days of confirming the exceedance. Assess Phase 2 Investigations. Is further action required? YES NO Phase 3 Investigation Undertake further action in consultation with the relevant government agencies and consultants, which could include selective re injection of water into aquifers to enhance recharge and targeted environmental protection measures. Figure 4: Trigger Action Response Plan for Groundwater Level Version 6 October 2018 Page 27

31 9.0 EXTERNAL REPORTING Within 2 weeks of approval of this WMP, a copy will be made available for public viewing via the MCC website. The performance of MCC s WMP will be reported through a number of external reporting requirements, which include; Annual Environmental Management Report (AEMR); EPL Annual Licence Return; Regular updates of monitoring results on the MCC website; and CCC Meetings. 9.1 ANNUAL ENVIRONMENTAL MANAGEMENT REPORT The AEMR will include a summary of: The site water balance; Water monitoring results and comparison to the trigger levels and monitoring results from previous years; Identification of any trends in the monitoring results; Review of the performance of management measures and the monitoring program; Identification of any non compliance against approval and licence conditions, and management measures undertaken to address any non compliance; and Summary of water related complaints and management measures undertaken REVIEW OF MANAGEMENT PLAN The WMP will be reviewed; Within 3 months of changes to Development Consent or licence conditions relating to water management or monitoring; Following reportable incidents at MCC relating to water management; Following an independent environmental audit which recommends changes to the WMP; At the completion of mining activities; and Every three years, or as directed by MSC, in accordance with Condition 14 (e) of the Development Consent Conditions. Version 6 October 2018 Page 28

32 11.0 RESPONSIBILITIES Table 9 outlines the responsibilities relating to the WMP. Table 9: Management Plan Responsibilities Position Task Timing General Manager Provide adequate resources to Annual review implement the requirements of the WMP Maintenance Maintain water meters As required Superintendent Coordinate calibration of water Annually meters Environmental Superintendent Notify regulatory authorities of any water related incidents Following any water related incident Coordinate response to all water related complaints Following a water related complaint Coordinate reviews of the WMP As outlined in WMP Coordinate monitoring as required in WMP (including maintenance and calibration) As required (minimum monthly) Coordinate reporting as required in WMP As required (minimum monthly) Version 6 October 2018 Page 29

33 Appendix 1: Correspondence Regarding Water Management Plan Version 6 October 2018 Page 30

34 Version 6 October 2018 Page 31