Subsidence Management Plan - Quetools

Mt Owen West DumpIt has been recommended by SCT (2006) that the impacts of miningsubsidence on the West Dump are assessed once the mining geometries andtiming of the proposed activities are better defined. The Mt Owen ComplexMining Operations Plan (MOP) dated January 2006 indicates that the area ofthe West Dump overlying the SMP Application Area will be rehabilitated in2009/2010. In this instance, the West Dump would not be impacted bysubsidence and no specific monitoring programs would be required.In the event that rehabilitation has not been completed, there would beexpected to be some potential for instability of the rock slopes due tosubsidence, although it is anticipated that these would be manageable.GCCM will provide monitoring data and other subsidence information toXMO to ensure that appropriate monitoring strategies can be developedwhere required.Mt Owen Eastern Rail PitIn the event that the Eastern Rail Pit is backfilled and rehabilitated prior toundermining as indicated within the Mt Owen EIS (Umwelt, 2003), theproposed longwall mining will not create a risk for either GCCM or XMOoperations (Umwelt, 2004d).In the event that the pit is used for a tailings dam as indicated by Xstrataduring the consultation process for this SMP and the Mt Owen ComplexMining Operations Plan (MOP) dated January 2006, the proposed changes willneed to be the subject of further development approval. These changes wouldneed to be assessed by XMO / Xstrata and considered by the approval bodyhaving regard to all information available at that time, including this SMP ifapproved. In this instance there would be expected to be some potential forinstability of the rock slopes due to subsidence. Inflows into the overburdenare likely to be reduced by sealing. Vertical subsidence may make it necessaryto build up the level of embankment control structures if the tailings dam isclose to full.GCCM has prepared a subsidence management plan for the Eastern Rail Pit,on the basis of consultation with Xstrata (Annex K). Under the terms of theDeed, XMO is not permitted to object to DPI or any other person about thisSMP which will include the management plan for the Eastern Rail Pit. GCCMwill cooperate with XMO to accommodate any reasonable changes arisingfrom their operational requirements up to the point that such changes do notimpede GCCM's ability to extract the coal and maximise the reserves in themanner that its mining lease requires.ENVIRONMENTAL RESOURCES MANAGEMENT AUSTRALIA 0038321/FINAL/3 JANUARY 200714