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CWI proposes to control subsidence within these renewable resource lands by <br />limiting the extraction of coal beneath these potentially impacted surficial <br />• aquifers. In areas of the renewable resource lands separated from the "D" <br />seam by less than 600 feet, extraction will be limited to six 20-foot wide <br />mains developed oa 120' by 80' centers, resulting in permanently retained 100' <br />by 60' pillars. Pillar stability calculations project Ashwin/Wilson safety <br />factoring is excess of 2.0 for pillars of that size at 600' of overburden <br />depth. Further, in areas of the renewable resource lands separated from the <br />"D" seam by between 600' and 800' of overburden, permanent 60' x 60' pillars, <br />with Ashwin/Wilson safety factoring in excess of 1.5, will be retained. In <br />both these areas, mining will be limited to development without retreat <br />extraction. <br />With the exception of ruins, the inventoried buildings will be protected by <br />the retention of solid coal pillars of 300' radius beneath each of the <br />potentially affected buildings. <br />CWI's strain projections anticipate potential, repairable damage (non-material <br />damage) to the two existing water pipelines, the Steven's Gulch Road, assorted <br />trails, ponds, and springs within the permit area. In each case, a preferred <br />repair methodology has been presented within the Subsidence Repair Handbook <br />portion of the amended permit application. <br />Calculations have been included to demonstrate that adequate water storage <br />exists in the Pitkin Mesa pipeline water distribution system to assure reduced <br />service and safe fire coverage in the event of a subsidence disruption of the <br />pipeline. <br />• CWI proposes a subsidence monitoring program with three components; visual <br />inspection, wide-spaced grid subsidence monumentation, and close-spaced <br />high-resolution subsidence monuments. The visual inspection phase consists of <br />a walk-over of the ground surface above mined areas with semi-annual <br />frequency. In future permit periods, when renewable resource lands and <br />structures may be undermined, pre- and post-mining inspections of structures <br />will be incorporated. The applicant also proposes daily inspections of the <br />Steven's Gulch Road, in order to protect the public. <br />Depending upon rates of mining advance and mine production, data from <br />high-resolution subsidence monument networks should begin to become available <br />in 1985. High-resolution subsidence data, with which to define the angle of <br />draw, will be generated during the next few years. Data collected from these <br />monument grids will allow verification, or support redesign, of the subsidence <br />control plans proposed by CWI for implementation in the future. <br />Fish and Wildlife - Threatened and Endangered Speeies, Raptors <br />The proposed extension of mining at the Orchard Valley mine will require <br />extension of the ventilation system of the workings into the western part of <br />the mining plan area. As part of the ventilation system, CWI will install a <br />surface ventilation fan in an as yet unidentified location in the western part <br />of Federal coal lease C-37210. There are three golden eagle nesting areas in <br />the mining plan area, one of which is in the western part of the mining plan <br />• <br />10 <br />