1999-12-14_GENERAL DOCUMENTS - C1981038

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life-of-mine azea. The Pitkin Mesa pipeline supplies potable water to roughly 160 domestic taps. Subsidence Control Plan - The operator has proposed a subsidence control plan to prevent material damage from occurring to the renewable resource ]ands within Steven's Gulch and East and West Roatcap Creeks. The U.S. Bureau of Land Management Lease C-37210 also bears stipulations addressing these same concerns. The operator proposes to control subsidence within these renewable resource lands by limiting the extraction of coal beneath these potentially impacted surficial aquifers. In areas of the renewable resource lands separated from the D seam by less than 600 feet, extraction will be limited to seven 20-foot wide mains developed on 120-by-80-foot centers, resulting in permanently retained 100-by-60-foot pillars. Pillar stability calculations project Ashwin/Wilson safety factoring in excess of 2.0 for pillars of that size a[ 600 feet of overburden depth. Further, in areas of the renewable resource lands sepazated from the D seam by between 600 and 800 feet of overburden, permanent 60-by-60-foot pillars, with Ashwin/Wilson safety factoring in excess of 1.5, will be retained. )n both of these aeeas, mining will be limited to development without retreat extraction. Technical Revision No. 17 (TR-17) and Technical Revision No. 19 (TR-19) address mine plan modifications to Panel B and Panel C respectively. These TR's modify the pillar size and spacing scheme described above, while maintaining the required safety factors. Both revisions were approved by the Division. With the exception of the ruins depicted as Structure No. 27, the inventoried buildings will be protected by the retention of solid coal pillars of 300-foot radius beneath each of the potentially affected buildings. The operator's strain projections anticipate potential, repairable damage (non-material damage) to the two existing water pipelines, the Steven's Gulch Road, assorted trails, ponds, and springs within the permit area. In each case, a preferred repair methodology has been presented within the Subsidence Repair Handbook portion of the permit application (Volume 3). Calculations have been included to demonstrate that adequate water storage exists in the Pitkin Mesa Pipeline water distribution system to assure adequate water supplies in the event of asubsidence-related disruption to the pipeline. The company does not propose to mine pillazs beneath the Pitkin Mesa Pipeline during the five-year permit term. Only development mining of main entries would occur under the pipeline and the Steven's Gulch Road within the Steven's Gulch buffer zone and no subsidence is projected. Bowie Resources Limited submitted a pipeline repair plan, signed by Pitkin Mesa Pipeline Company as a condition of the approval of TR-19. Technical Revision No. 22 modified the coal lease and permit boundary to the west. The new permit boundary includes areas in the Long Draw Drainage. Upper Cabin 43