2009-02-19_PERMIT FILE - C1982056A (3)

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material. 'I`he ~eoteclinical. investi<Jation shall be plaruied and Supervised by an engineer or en inecring~loai4t according to the tollo~v2tl • (i) 'I`he number location and depfh of boringand test pits ;hall be determined u~itl~ current ptl~derft eneiineerin~j practice for the size of dam or enlbanlcment quantity of material to be impounded and subscn-iace conditions. (ii.) The chaa•actcr of the overburden and bedrock tlte~roposed abutment sites a1~d anti adverse ~eoteclulical conditions ~v Mich may affect the particular dam embankment or reservoir site; shall be considered. ~i~ All spi~in~s seek and ~raund c~:-ater flow obtien~ed or anticipated during wet ~~eriods in the area of the proposed dam or embankment shall be identified on each larl (iv) An analysis shall be made of the en ineerina safe;t~~ and environmental protection factors to allc>~v for the possibility of mudt7ocvs rock-debris falls or other landslides into the dam embankment or impoundcci material. RESPONSE TCC constructed a coal preparation plant (Washplant I) in late 1994-1995. The preparation plant was designed to process low quality coal, which included low quality stockpiled at the time or produced by ongoing mining operations. The resulting clean coal was stockpiled in the preparation plant area and then placed on the overland belt for transportation to the tipple. In the interim period (prior to preparation plant construction) a low quality coal stockpile was constructed on top of • the existing waste rock disposal site. This coal was processed through the plant to provide a product with approximately 10 percent ash It was anticipated the plant would operate at a 60-65 percent efficiency rate. The clean coal was place onto the overland conveyor belt and conveyed to Tipple 2. The coal was then processed through the tipple and placed in the coal stockpile and shipped to Twentymile customers. TCC also initiated site grading, road relocation, drainage construction/modification, and other necessary site preparation activities prior to construction of the preparation plant construction. In the future, it may be economical to retrofit a centrifuge drying operation or other appropriate facilities into the crushing and screening building, shown on Map 24, Surface Facilities, or at other appropriate locations. The economics on whether to proceed with a centrifuge drying operation depends on how well underground water can be kept out of the mining face. Operational experience to date indicates underground water control measures will be adequate. If a centrifuge dewatering facility is retrofitted in the future, the coal processing waste from the centrifuges would most likely be piped to a treatment pond constructed and operated in accordance with these rules under an approved permit. At this time, Twentymile Coal Company does not intend to install a coal processing or coal cleaning plant at the Fish Creek Tipple operation. 9) linder~routad I)evelopme~atal Waste A .earl°at.ive and a~ropriate maps and cross-sections prepared to meet the standards of 2 1 {) deSCribinz the proposed disposal methods and sites for lp acitag under~roualcl develot~ment ~~~aste a~ld excess spoil generated at :7 MR08-230 2.05-91 09/05/08