Extraction Plan - Peabody Energy

Extraction Plan – North Wambo Underground Mine Longwalls 7 and 8A summary of the key potential consequences/hazards associated with Longwalls 7 and 8, asidentified in the risk assessment workshop is provided in Table 7. The table also provides across-reference to where these key potential consequences/hazards have been addressed in theExtraction Plan.Table 7Key Potential Consequences/Hazards Identified by the Subsidence Risk AssessmentSubjectAreaNaturalFeaturesFarm Landand FacilitiesPublicUtilitiesMineInfrastructurePotential Consequence HazardInduced leakage from Wollombi Brook resulting from alowering of the watertable associated with the extractionof Longwalls 7 and 8.A change in flood regimes or extent of potential inundationdue to subsidence resulting from the extraction ofLongwalls 7 and 8.Reduced baseflow to Wambo Creek (also known asSouth Wambo Creek) resulting from a lowering of thewatertable associated with the extraction of Longwalls 7and 8.Failure of the monitoring program to detect and respondto an impact on the groundwater system.Induced leakage from Stony Creek resulting from alowering of the watertable associated with the extractionof Longwalls 7 and 8.Induced leakage from North Wambo Creek overLongwalls 7 and 8 due to a lowering of the watertableand/or connective cracking associated with the extractionof Longwalls 7 and 8.Reduced groundwater user access to alluvial groundwatersupply due to a lowering of the watertable associated withthe extraction of Longwalls 7 and 8.Erosion and geomorphological impacts on North WamboCreek above predicted impacts.A change in land surface slope and preferential pathwaysfor rainfall infiltration resulting from fracturing to the landsurface caused by the extraction of Longwalls 7 and 8.Far-field subsidence impacts due to the extraction ofLongwalls 7 and 8 resulting in environmentalconsequences at Wollemi National Park.Potential impacts on neighbouring properties andactivities.Subsidence impacts resulting in injury to livestock due tothe extraction of Longwalls 7 and 8.Subsidence impacts to the 11 kilovolt (kV) Ausgridpowerline located within the Longwalls 7 and 8 ApplicationArea resulting from the extraction of Longwalls 7 and 8.South Wambo Dam damaged by subsidence resulting indischarge of dirty water, delay to operations or inrush toworkings.Mine subsidence impacts resulting in slope instability ofwaste rock emplacements.Subsidence impacts to WCPL powerlines resulting fromthe extraction of Longwalls 7 and 8.Extraction PlanReferenceSection 3.1 and WMP(Appendix A)Section 3.2 and LMP(Appendix B)Section 3.3 and BMP(Appendix C)Sections 2, 3.2 and 3.6Section 3.2 and LMP(Appendix B)Section 3.4 and BFMP(Appendix D)Section 3.4 and BFMP(Appendix D)EP/SMP LW7-8 Rev B December 2012 Page 23