Extraction Plan - Peabody Energy

Extraction Plan – North Wambo Underground Mine Longwalls 7 and 8Table 13Management Issues for Land in General Associated with the Extraction of Longwalls 7 and 8Issue Approved Impact Revised Impact Monitoring ManagementLand Use. • Surface cracking. 1• Surface cracks of widths • Monitoring of subsidenceLand • Increased erosion. 1ranging between 40 and in accordance with theCapability520 mm aboveSubsidence MonitoringLongwalls 7 and 8. 2Program (Appendix H).SteepSlopesSurfaceWater• Ponding of surface water inareas where isolateddepressions form. 1• Increased depth and durationof inundation during floodevents. 1• Surface cracking. 1• Addressed in the WMP(Section 3.1).• Maximum potentialponding depths between0.15 and 1.3 m aboveLongwalls 7 and 8. 2• No long term impacts onland capability areexpected to result fromthe extraction ofLongwalls 7 and 8.• No steep slopes occurwithin the Longwalls 7and 8 Application Area. 2• Cracking may occuroutside of the Longwalls 7and 8 Application Areawhere moderate to steepslopes exist. 2• Addressed in the WMP(Section 3.1).• Visual observations ofstock fences.• Visual observations of theground surface.• Addressed in the WMP(Section 3.1).1 After the EIS (WCPL, 2003).2 After DgS (Technical Report 1).* Minor cracks that develop are not expected to require remediation as geomorphologic process will result in naturally filling of these cracks over time.• Notification to agistees of areas oflongwall mining and activesubsidence, and exclusion ofagistment grazing from areas wheresurface cracking presents areasonable risk to people and/orlivestock.• Remediation of surface cracks* wherepracticable using conventionalearthmoving equipment (e.g. abackhoe) including:– infilling of surface cracks with soilor other suitable materials; or– locally re-grading andre-compacting the surface.• Stabilisation of any areas of surfacecracking using erosion protectionmeasures (e.g. vegetation planting).• Drainage works and rehabilitation ofsubsidence troughs (i.e. areas ofinduced ponding) as necessary.• Repair of stock fences prior toallowing access for agistment grazing.• Management measures in accordancewith the ESCP.• Addressed in the WMP (Section 3.1).EP/SMP LW7-8 Rev B December 2012 Page 37