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<br />Subsidence Control Plan <br />The operator has proposed a subsidence control plan to prevent <br />material damage from occurring to the renewable resource lands within <br />Steven's Gulch and East and West Roatcap Creeks. The U.S. Bureau of <br />Land Management Lease C-37210 also bears stipulations addressing these <br />same concerns. <br />The operator proposes to control subsidence within these renewable <br />resource lands by limiting the extraction of coal beneath these <br />potentially impacted surficial aquifers. In areas of the renewable <br />resource lands separated from the D seam by less than 600 feet, <br />extraction will be limited to seven 20-foot wide mains developed on <br />120-by-80-foot centers, resulting in permanently retained <br />100-by-60-foot pillars. Pillar stability calculations project <br />Ashwin/Wilson safety factoring 'in excess of 2.0 for pillars of that <br />size at 600 feet of overburden depth. Further, in areas of the <br />renewable resource lands separated from the D seam by between 600 and <br />800 feet of overburden, permanent 60-by-60-foot pillars, with <br />Ashwin/Wilson safety factoring in excess of 1.5, will be retained. In <br />both of these areas, mining will be limited to development without <br />retreat extraction. Technical Revision No. 17 (TR-17) and Technical <br />Revision No. 19 (TR-19) address mine plan modifications to Panel B and <br />Panel C respectively. These TR's modify the pillar size and spacing <br />scheme described above, while .maintaining the required safety <br />factors. Both revisions were approved by the Division. <br />With the exception of the ruins depicted as Structure No. 27, the <br />inventoried buildings will be protected by the retention of solid coal <br />pillars of 300-foot radius beneath each of the potentially affected <br />buildings. <br />The operator's strain projections anticipate potential, repairable <br />damage (non-material damage) to the two existing water pipelines, the <br />Steven's Gulch Road, assorted trails, ponds, and springs within the <br />permit, area. In each case, a preferred repair methodology has been <br />presented within the Subsidence Repair Handbook portion of the permit <br />application (Volume 3). <br />Calculations have been included to demonstrate that adequate water <br />storage exists in the Pitkin Mesa Pipeline water distribution system <br />to assure adequate water supplies in the event of a subsidence-related <br />disruption to the pipeline. The company does not propose to mine <br />pillars beneath the Pitkin Mesa Pipeline during the five-year permit <br />term. Only development mining of main entries would occur under the <br />pipeline and the Steven's Gulch Road within the Steven's Gulch buffer <br />zone and no subsidence is projected. COVCC submitted a pipeline <br />repair plan, signed by Pitkin Mesa Pipeline Company as a condition of <br />the approval of TR-19. <br />Technical Revision No. 22 modified the coal lease and permit boundary <br />to the west. The new permit boundary includes areas in the Long Draw, <br />which lies within the West Roatcap Creek drainage. Upper Cabin <br />Spring, water supply for Stucker Mesa Domestic Water Company, is <br />-41- <br />