2016-07-27_PERMIT FILE - C1982056A (2)

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material. The (Yeotechnical. investigation shall be planned and supervised by an engineer or engineering geologist, according to the following • (i) The number, location and doth of borings and test pits shall be determined using current prudent engineering practice for the size of dam or embankment quantity of tnaterial to be impounded and subsurface conditions. (ii.) The character of the overburden and bedrock tlte2roposed abutment sites and anti adverse aeoteclmical conditions which may affect the particular dam embankment, or reservoir site shall be considered. �i All springs seek and ground water flow observed or anticipated during wet tReriods in the area of the proposed dam or embankment shall be identified on each plan. (iv) An analysis shall be made of the engineering safety and environmental protection factors to allow for the possibility of mudflows rock -debris falls or other landslides into the dam embankment or impounded 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. :7 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) t7.ndertrrouta.d De.velopmeta.tal Waste A narrative and anpropriate maps and cross-sections prepared to meet the standards of 2.10., describia the proposed disposal methods and sites for1p acitag undergromid development waste and excess spoil generated at MR08-230 2.05-91 09/05/08