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Caa/Me!/~ane Drainage Pmjeet- Paneb 7G-24 Wert E!k Marc • Page 1-7 1.3.5 Drill and Complete MDWs and Drill and Log Exploration Drillholes MDWs and exploration drillholes would be drilled from the drill pads constructed over each of the progressive longwall mining panels. MCC would drill vertical or neaz-vertical MDWs wherever feasible. Where this is not possible due to access or environmental constraints, it may be necessary to drill one or more angled MDWs Erom a single drill pad to intercept the tazget locations above [he coal seam. The locations of the proposed drill pads and MDWs are shown on Map Ml, Project Atea Activities With Surface Stipulations. Completion of approximately 70 MDWs and up to 10 exploration drilllaoles is proposed. Up to 18 MDWs and 4 exploration drillholes would be drilled during each yeaz of the program. MDWs and exploration drillholes would typically be drilled using truck-mounted drill rigs and standard rotary (tricone roller bits) and downhole hammer drilling methods. Drilling circulation media, used to lift drill cuttings from the dtillhole and stabilize the hole during drilling operations, would normally include air, water; and biodegradable polymer foams. Gels, surfactants, and bentonite-based drilling muds would also be used to stabilize the drillhole, if necessary. Other materials, including crushed peanut shells, cottonseed hulls, and cedar Fibers could also be added to the circulation medium to help seal the walls of the hole to maintain circulation. All drilling fluids and additives that could be used are either naturally occurring inorganic or organic materials or biodegradable compounds, Water for drilling operations would be pumped to individual drill sites from portable tanks using high pressure hose. Drilling water would be obtained from the mine dewatering system or other sources for which MCC has applicable or can obtain water rights. All drilling fluids and cuttings would be contained on the drill pad in mud pits or portable tanks. Earthen berms on the perimeter of the drill pads, designed to intercept and contain mnoff from the pad azea, would also serve as secondary containment to prevent the release of drilling fluids from the pad area. MDWs would be completed and cased with cemented steel casing, as shown on Figure F3, Typical Methane Drainage Well Construction/Completion. The casing prevents deterioration of the drillhole and maintains an open flow path for methane drainage. Cementing the casing in the borehole prevents flow of either gas or water in the annulus between the casing and borehole and prevents contamination of ground water or mixing between ground water sources. Control valves would be installed on the surface casing to control methane flow. Blow-out preventers aze not necessary on the well heads since the project area is not a producing gas field, high pressure gas has. not been encountered in any previous drilling in the azea, and the coal bed methane present is not pressurized and is typically released very slowly under natural conditions. Exploration drillholes would be completed, logged (to obtain information on geology and coal and overburden occurrence and characteristics), and then plugged and sealed, completed as a MDW, of completed for monitoring or other uses acceptable to both the USFS, MSHA, the CDMG, and MCC. Following completion of drilling activities for [he MDWs and any exploration drillhole, the size of each drill pad would be reduced by reclaiming all pad azeas except those areas required for MDW operation and access. Generally, this would involve reduction in the pad size from 0.5 acres to approximately 0.05 acres and reclamation of the remainder. One or more of the initial drill pads within each of the three mining districts (Panels 14-175, Panels 18-20, and Panels 21-24) would be used as a staging azea for temporary storage of equipment and supplies for subsequent pad construction and drilling. For those pads used as staging azeas, pad reduction and interim reclamation would be deferred until all drilling was completed in the corresponding ttilning district. I vmnrv...,v.uor~roy, u.,mu wFr Environmental.9.rrerrment i/s/oz.s