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<br /> <br />§2.05 APPLICATION FDR PERMIT FOR SURFACE OR UNDERGROUND MINING ACTIVITIES -MINIMUM <br />REQUIREMENTS FOR OPERATION AND RECLAMATION PLAPIS. <br />2,05.6 Mitigation of Surface Coal Mining Operation Impacts (cont'd,) <br />(6) The information, predictions, inventories and plans within the <br />existiny approved permit remain unchanged by the construction <br />of the Orchard Valley West portal except as noted in Section <br />2, 05.6(6)(b)(i)(R) and 2.05,6(6)(c)(i)(R), Section 2.OS,fi(6) <br />(b)(i)(B) was revised based on a slightly different entry de- <br />sign from the existing permit, Section 2,05,6(6)(c)(i)(R) was <br />revised to add new widely spaced monuments within the area to <br />be mined within the remaining permit term and the next permit <br />term. <br />(6)(b)(i)(B) <br />All of the subsidence information provided in the existing <br />permit application is the same except that CWl~will drive <br />seven entries instead of the approved six under Steven's C•ulch <br />and East Roatcap Creek, The seven entries will consist of: <br />three developed on 120' X 150' centers and four developed on <br />120' X 100' centers, which results in nominal pillar Sizes of <br />100' X 130' and 100' X RO' respectively, Pillar stability <br />design developed by Wilson (1972) was previously completed on <br />projected 120' X 80' centers within this area, Calculations <br />for 120' X RO' centered entries had a safety factor in excess <br />of 2. The ,„~yer 120' X 150' centered entries and 120' X 100' <br />centered entries will increase the safety factor over the pre- <br />viously approved pillar size (refer to Pillar Stability Calcu- <br />lations in Volute 2), <br />(6)(c)(i)(R) <br />All of the subsidence monitoring program will remain the same <br />as the existing permit except that additional wide-spaced grid <br />monuments will be installed over Orchard Valley West mining <br />projections, Some widely spaced yrid monuments will not yield <br />further information on subsidence, Either the stations will <br />not be undermined ~~ ~~~~~~^ying began too long after secondary <br />retreat mining and subsequent subsidence effects were not de- <br />tected, Stations 3, 4, and 5 have not heen undermined and CWI <br />does not intend to undermine these monuments, The remaining <br />monuments (1, 2, 9, 10, and 11) were surveyed initially after <br />secondary retreat mininy and future additional information due <br />to subsidence effects cannot be obtained from these monuments <br />because no movement has been detected, <br />Additional wide-spaced grid monitoring stations will be con- <br />structed to analyze subsidence effects within the proposed <br />area of Orchard Valley West mining during the remaining permit <br />tenn (see Map 3-1 ). The areas of immediate concern are the <br />lands within Steven's Gulch and East Roatcap Creek drainages, <br />Monitoring stations 90, 92 and 93 will be installed in 1987 to <br />allow monitoring of the land within East Roatcap Creek, <br />24 <br />"t_ I i _ <br />