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• 2.05 APPLICATIOd4 FOR PERMIT FOR SURb7,L'E OR tAIDE[~GROZJtd) MINING ACPIVITIES - MINIAlIII~i REQUIRII~lfS FOR OPERATION AMID RECLAMATION PI.AUiS. 2.05.6 Mitigation of bvrface Coal Mining Operation Eaq~acts. (COnt'd.) (6) (f) (i) (B) (Cont'd.) subsidence or abandoned mine subsid visual monitoring will enable CWI to described in the Subsidence repair necessary (6) (f) (ii) ence would not occur. Continued implement repair procedures Handbook (Volume 3), where During this initial permit term, mining is not projected beneath any Renewable Resource Lands, identified structures, or other features such as pipelines, powerlines, and roads. If during subsequent subsidence monitoring, the subsidence effects differ greatly frwn the predicted effects, the following subsidence control plan will be modified to ensure damage or diminution of the foreseeable use would not ocarr. J The subsidence study performed by Geo-Hydro Consulting, Inc. aryl presented in the Subsidence Appendix, Volume 3, determined that material damage or diminution of the foreseeable use of the permit area would not occur. Near surface, colluvial/alluvial deposits are present within Stevens (filch and East Roatcap Creek and constitute Renewable Resource Lands. See Map No. 9-1. The following subsidence control plan is proposed during subsequent permit terms. Federal lease C-377210 stipulation "g" limits extraction beneath Steven's Gulch and East Roatcap Creek to necessary development access entryways below 600 feet of overburden thickness. In ccmq~liance with BLM stipulation "g", CbV will drive access entryways only beneath the Stevens Gulch aril East Roatcap Creek drainage buffer zones under 600 feet of overburden. Permanent protective pillars will be left standing to prevent all surface and subjacent disturbance to the overburden. Protective pillars in these buffer zones will be designed to provide safety factors in excess of 2.0 using the Wilson pillar design method (refer to Pillar Stability Calculations in Volume 2). Panel designs for specific development geometries and mining heights vary within these buffer zones and are optimized to provide maxim~nn economic recovery of the coal resource, however, the minimum safety factor criteria for all panels developed within these buffer zones remains constant at 2.0. Secondary extraction or retreat mining is limited to the recovery of floor coal within previously developed entries. All development entries are roof bolted in accoxclance with the approved roof control plan in effect. • TR 92-19 Revised 6/08/92 156