Subsidence Management Plan - Quetools

Subsidence Management Plan - Quetools Subsidence Management Plan - Quetools

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7.4 INDUSTRIAL, COMMERCIAL AND BUSINESS ESTABLISHMENTSRavensworth East PitA specific management plan has been developed for the Ravensworth EastTailings Pit (TP2) within the Application Area (Annex J). GCCM will providemonitoring data and other subsidence information to XMO to ensure thatappropriate management strategies can be developed.The Mt Owen Complex MOP (2006) has identified the southern tailings pit asan emplacement area until 2010. The ‘Staged Mining and Rehabilitation Planas at Year 2010’ identifies the southern portion of the TP2, above Longwalls 15to 17, as ‘proposed future tailings emplacement area – subject to Section 126Application’ (Mt Owen MOP, 2006). The proposed GCCM operations will notundermine the southern tailings pit until late 2011, but the final use of thesouthern tailings pit at that date cannot be confirmed. Without specific detailof the geometries and status of the pit when it is due to be undermined, it isdifficult to be precise about the likely subsidence impacts. However, therewould not appear to be any impediment to managing these impacts throughcontrol of the tailings level and building up of perimeter bunds subject tovertical subsidence.GCCM has prepared a specific management plan for the Ravensworth EastTailings Pit (Annex J). Under the terms of the Deed, XMO is not permitted toobject to DPI or any other person about this SMP which will include themanagement plan for the Ravensworth East Tailings Pit. GCCM willcooperate with XMO to accommodate any reasonable changes arising fromtheir 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.Glendell Open Cut and Haul RoadSubsidence impacts on the Glendell Open Cut are likely to be insignificant andimperceptible for all practical purposes because it is located outside theApplication Area and no specific management measures have beenrecommended.Similarly, the Glendell haul road is not expected to be perceptibly affected bymining subsidence and no specific management measures have beenrecommended.The edges of the Glendell overburden dump, as indicated in their latestApplication to Carry Out Open Cut Mining Operation dated February 1998,would be expected to experience vertical subsidence up to about 1.5m. Somelateral dilation of the dump slopes would be expected and surface crackingmay be evident near the top of the slope. It is assumed that any futureENVIRONMENTAL RESOURCES MANAGEMENT AUSTRALIA 0038321/FINAL/3 JANUARY 200722

application for mining approval would need to be developed by Xstrata, andconsidered by the approval body, having regard to all information available atthat time, including this SMP if approved.Glendell has accepted liability for subsidence damage which might be causedto its overburden dump by reason of GCCM's undermining. Specifically, inthe MPLA Agreement, Glendell agreed to:indemnify MMC against all claims costs demands losses or expenses suffered byGlendell for which MMC would otherwise be liable in connection with damage tothe emplacement due to subsidence arising out of or in connection with MMC'sunderground mining activities carried out under CL 382 on the Land providedthat the mining is carried out my MMC in accordance with approvals from theDepartment of Mineral Resources.Managing and repairing any subsidence damage to the overburden dump istherefore the responsibility of Glendell and no specific management strategieshave been recommended.Mt Owen West DumpThe Mt Owen Complex Mining Operations Plan (MOP) dated January 2006indicates that the area of the West Dump overlying the SMP Application Areawill be rehabilitated in 2009/2010. In this instance, the West Dump would notbe impacted by subsidence and no specific management strategies have beenrecommended.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, the proposed changes willneed to be the subject of further approval and such changes would need to beassessed by XMO/Xstrata, and considered by the approval body, havingregard 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.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 notENVIRONMENTAL RESOURCES MANAGEMENT AUSTRALIA 0038321/FINAL/3 JANUARY 200723

7.4 INDUSTRIAL, COMMERCIAL AND BUSINESS ESTABLISHMENTSRavensworth East PitA specific management plan has been developed for the Ravensworth EastTailings Pit (TP2) within the Application Area (Annex J). GCCM will providemonitoring data and other subsidence information to XMO to ensure thatappropriate management strategies can be developed.The Mt Owen Complex MOP (2006) has identified the southern tailings pit asan emplacement area until 2010. The ‘Staged Mining and Rehabilitation <strong>Plan</strong>as at Year 2010’ identifies the southern portion of the TP2, above Longwalls 15to 17, as ‘proposed future tailings emplacement area – subject to Section 126Application’ (Mt Owen MOP, 2006). The proposed GCCM operations will notundermine the southern tailings pit until late 2011, but the final use of thesouthern tailings pit at that date cannot be confirmed. Without specific detailof the geometries and status of the pit when it is due to be undermined, it isdifficult to be precise about the likely subsidence impacts. However, therewould not appear to be any impediment to managing these impacts throughcontrol of the tailings level and building up of perimeter bunds subject tovertical subsidence.GCCM has prepared a specific management plan for the Ravensworth EastTailings Pit (Annex J). Under the terms of the Deed, XMO is not permitted toobject to DPI or any other person about this SMP which will include themanagement plan for the Ravensworth East Tailings Pit. GCCM willcooperate with XMO to accommodate any reasonable changes arising fromtheir 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.Glendell Open Cut and Haul Road<strong>Subsidence</strong> impacts on the Glendell Open Cut are likely to be insignificant andimperceptible for all practical purposes because it is located outside theApplication Area and no specific management measures have beenrecommended.Similarly, the Glendell haul road is not expected to be perceptibly affected bymining subsidence and no specific management measures have beenrecommended.The edges of the Glendell overburden dump, as indicated in their latestApplication to Carry Out Open Cut Mining Operation dated February 1998,would be expected to experience vertical subsidence up to about 1.5m. Somelateral dilation of the dump slopes would be expected and surface crackingmay be evident near the top of the slope. It is assumed that any futureENVIRONMENTAL RESOURCES MANAGEMENT AUSTRALIA 0038321/FINAL/3 JANUARY 200722

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