Austar Stage 2 Subsidence Management Plan – Environmental Attributes, Impacts and Controls
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Austar Coal Mine Pty Ltd Austar Stage 2 Subsidence Management Plan – Environmental Attributes, Impacts and Controls February 2007 Austar Stage 2 Subsidence Management Plan – Environmental Attributes, Impacts and Controls Prepared by Umwelt (Australia) Pty Limited on behalf of Austar Coal Mine Pty Ltd Project Director: Peter Jamieson Project Manager: Peter Jamieson Report No. 2274/R06/V2 Date: February 2007 2/20 The Boulevarde PO Box 838 Toronto NSW 2283 Ph: 02 4950 5322 Fax: 02 4950 5737 Email: [email protected] Website: www.umwelt.com.au TABLE OF CONTENTS 1.0 Introduction and Background .................................................... 1 2.0 Characterisation of Surface and Sub-surface Features .......... 1 2.1 Natural Features ...................................................................................1 2.1.1 Surface Water Resources and the Catchment Area ..........................................1 2.1.2 Groundwater Resources.....................................................................................3 2.1.3 Swamps, Wetlands and Water Related Ecosystems .........................................4 2.1.4 Escarpments and Rock Formations ...................................................................4 2.1.5 Soils....................................................................................................................4 2.1.6 Flora....................................................................................................................5 2.1.7 Fauna..................................................................................................................5 2.1.8 Threatened Species ...........................................................................................5 2.2 Areas of Environmental Sensitivity ....................................................6 2.2.1 Areas as per 6.6.3 list SMP Guidelines..............................................................6 2.2.2 Significant Surface Watercourses and Groundwater Resources.......................6 2.2.3 Flood Prone Areas..............................................................................................7 2.2.4 Areas Containing Significant Ecological Values.................................................7 2.2.5 Surface Features of Community Significance ....................................................7 2.2.6 Areas of Agricultural Productivity .......................................................................7 3.0 Aboriginal Heritage ..................................................................... 8 4.0 European Heritage ...................................................................... 9 5.0 Subsidence Impacts.................................................................. 10 5.1 Overview of Predicted Subsidence Impacts ....................................10 5.2 Landform and Surface Water Resources .........................................11 5.2.1 Ellalong Lagoon................................................................................................12 5.3 Aboriginal Heritage and Archaeological Sites.................................12 5.4 Groundwater Resources....................................................................12 5.5 Flora and Fauna..................................................................................13 6.0 References ................................................................................. 14 Umwelt (Australia) Pty Limited 2274/R06/V2 February 2007 i FIGURES 1 Quorrobolong Creek, Cony Creek and Other Natural Features................1 2 Quorrobolong Creek Cross Sections..........................................................2 3 Cony Creek Cross Sections.........................................................................2 4 Previously Recorded Aboriginal Heritage Site within Stage 2..................8 5 Existing Landform ......................................................................................11 6 Predicted Landform following Mining of Longwall A3 ............................11 7 Predicted Landform following Mining of Longwalls A3 and A4..............11 8 Predicted Landform following Mining of Longwalls A3, A4 and A5 .......11 PLATES 1 Quorrobolong Creek (Cross-section 1).......................................................2 2 Quorrobolong Creek (Cross-section 2).......................................................2 3 Quorrobolong Creek (Cross-section 3).......................................................2 4 Quorrobolong Creek (Cross-section 4).......................................................2 5 Cony Creek (Cross-section 5)......................................................................2 6 Cony Creek (Cross-section 6)......................................................................2 7 Rabbit warrens on lower slopes of spur within Stage 2............................3 8 Bedrock escarpment within Stage 2 ...........................................................4 APPENDICES 1 Ecological Assessment Umwelt (Australia) Pty Limited 2274/R06/V2 February 2007 ii 1.0 Introduction and Background Austar Coal Mine is an aggregate of the former Ellalong, Pelton, Cessnock No.1 (Kalingo) and Bellbird South Collieries near Cessnock (see Figure 1). The mine is to be developed in three stages with Stage 1 comprising two longwall panels (A1 and A2), Stage 2 comprising three longwall panels (A3, A4 and A5) and Stage 3 for which mine planning is still being undertaken. This report provides an assessment of environmental aspects of longwall mining in Stage 2 and forms part of the Subsidence Management Plan prepared by Austar Coal Mine. The report has been prepared in accordance with the requirements for the preparation of Subsidence Management Plans (SMP) (Department of Mineral Resources, December 2003). This document addresses the environmental issues that are to be addressed in accordance with the Department of Primary Industries (Minerals) guidelines for the preparation of SMPs. Other SMP requirements are addressed by Austar Coal Mine and other specialists. This document includes: • a description of natural features; • a description of environmentally sensitive areas; • a description of the known and potential cultural heritage sites; and • a description of the likely impact of subsidence on the natural features, environmentally sensitive areas and cultural heritage. 2.0 Characterisation of Surface and Sub-surface Features 2.1 Natural Features 2.1.1 Surface Water Resources and the Catchment Area The Stage 2 study area is located immediately to the south of Broken Back Range (see Figure 1). The area encompasses the gentle south facing lower slopes of the Broken Back Range and the extensive creek flat of the Quorrobolong Creek system. The highest elevation in the study area is 161 metres above sea level and forms part of a northwest- southeast oriented spur that extends from the crest of Broken Back Range to a knoll that is located adjacent to the northern bank of Quorrobolong Creek. The creek flat that encircles this knoll typically has an elevation of approximately 125 mAHD. Slopes in the area of the floodplain range between 1% and 5% with the southern face of the knoll exhibiting near vertical sections. The major drainage line through the area is Quorrobolong Creek which is a fourth order stream. Quorrobolong Creek enters the study area in the south western corner of Longwall A5. At this location the creek has a bed elevation of approximately 125 mAHD. From this point the creek flows in a northerly direction for approximately 550 metres to its confluence with Cony Creek which is approximately at the western edge of Longwall A5. At this location the creek system has a bed elevation of approximately 120 mAHD. Quorrobolong Creek Umwelt (Australia) Pty Limited 2274/R06/V2 February 2007 1 above Longwall A5 is characterised by an incised channel that is typically 2 to 5 metres wide at the base and 8 to 10 metres wide at top of bank. The creek banks have steep sides which are typically 2 to 3 metres high and stable. The creek above Longwall A5 is bounded on either side by a thin strip of riparian vegetation. A series of off-stream farm dams are located on the western side of the creek. Upstream of the confluence Cony Creek exhibits a broad channel that has a base width of approximately 6 to 10 metres and a top of bank width of approximately 30 to 40 metres and bank heights of 2 to 3 metres. At the eastern edge of Longwall A5, Cony Creek has a bed elevation of approximately 120.5 mAHD. Upstream of the confluence Cony Creek is lined by riparian vegetation that varies in width from one row of trees to approximately 50 metres. Immediately downstream of the confluence, the channel narrows to be approximately 20 metres wide at top of bank. The northern bank of the creek is confined by a steep rock outcrop that is located on the southern face of a knoll. The top of the knoll has an elevation of approximately 160 mAHD which is 40 metres above the bed of the creek. This section of the creek is a natural constriction that acts as a control to flows in the Quorrobolong and Cony Creek systems upstream of the knoll. Quorrobolong Creek from the confluence flows due west and maintains a similar channel profile to the western edge of Longwall A3 which is approximately 900 metres downstream of the confluence. This section of the creek exhibits a sandy substrate and scattered and discontinuous riparian vegetation. At the western edge of Longwall A3 Cony Creek has a bed elevation of approximately 118.5 mAHD. Quorrobolong Creek flows into Ellalong