2007-06-29_PERMIT FILE - C1981022A (2)

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Sc+var - 2.05.3 workings. Fourteen Sanborn Creek Mine borehole locations are shown on the General Facilities Map (Map Z.OS-Ml, Sheet 4 of 6). Elk Creek Mme borehole locations are shown • on General Facilities Map (Map 2.05-M1, Sheet 6 of 6). Exhibit 2.04-E3, Item 9 provides a sununary all of the OMLLC methane drainage wells. Hydrologic considerations for "typical" borehole locations are found in Exhibit 2.05-E3, Section 9. Each gob vent borehole or group of boreholes will be permitted separately as minor or technical revisions. Revision submittals will address specific details relative to location, access, resource protection, and drainage and sediment control. Surface disturbance associated with these borehole activities is limited to light-use roads utilized to access the well sites and graded pad areas utilized for drilling activities and installation of surface degasification equipment. Well sites have been selected to min;mi~e new surface disturbance, where possible. Well sites can often be accessed using existing unimproved powerline, ranch roads or exploration roads. Mmor road improvements such as grading and widening in certain areas may be necessary to provide for drill and equipment access dependent on existing road conditions. In addition, dependent on survey results, the actual drill site maybe beyond the limits of existing roads, requiring road extensions. To the extent feasible, borehole sites are located so that access roads can provide access for one or more degasification installations. Well pad areas are typically a maximum of 100' x 200'. If multiple wells are drilled from the same pad, the dimensions of the pad will be larger, but typically will be less total disturbance than the sum of the individual pad dimensions. Site development involves the minor road improvements noted above, establishment of temporary upslope drainage diversion (if necessary} to carry runoff around the pad area, site clearing, removal and windrowing of topsoil (or suitable soil material) in stockpiles or a berm on the erimeter of the pad azea, • rading of the pad area, and excavation of temporary mud pits for containmem of drilling fluids during drilling activities. Wells will be drilled to a depth of up to 2,500 feet below the ground surface to intercept the mine workings or seam to be mined. A conventional truck- mounted rotary drill rig is typically utilized to drill the well using rotary air, foam, and/or wet (mud) drilling methods to advance and nraurtain the physical integrity of the well. The wells have been and will be cased with conventional grouted steel casing for the entire length except for the portion of the borehole extending from approximately 200-feet above and into the mine workings, which is cased with perforated steel casing to ma~r;m;>P gas exuaction. Gas extraction is achieved by connecting a trader mounted vacuum pump to the well(s) that creates a negative pressure, drawing methane and other gases from the mine workings to and through the wells}. The vacuum pump is gas-powered, utilizing the methane extracted through the well as the primary fuel source and propane as the star-up fuel source for initial well pressurization. Any excess methane not utilized to fuel the degasification pump is vented or in the future maybe flared-off or used in a small power generator. The degasification installations will continue to be operated so long as needed to prevent or m;nimi~e methane in the mine and/or seepage of methane from the sealed mine workings into active mine areas. The degasification installations are inspected on a periodic basis and the associated light-use road and operating equipment aze maintained as necessary to assure continued effective operation. When the degasification installations are no longer required, surface facilities and equipment will be removed and associated surface disturbance aeeas will be redauned as described in the reclamation plan section. Pre-existing unimproved public roads and roads requested to be left in place by surface owners maybe retained. To prevent leakage of methane, a seal or plug will be placed in the casing as deep as possible and the well string filled with cement to within 10 feet of the surface. The DMG Methane Drainage and • Monitoring Well guidance document is a good source of guidance and will be consulted in accordance with Rule 1.15.4. If a borehole is to be retained as a methane production well, it will be permitted with the Colorado Oil and Gas Conservation Commission. TR4R 2.05-20 Revised October 2004