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<br /> <br /> <br />,1! td 1 N 1982 <br />MIPJED LAND RECI_AP~IATIDN <br />Colo. Dept. of Natural Resources <br />June 16, 1982 <br />Mr. Robert Liddle <br />Mined Land Reclamation <br />Department of Natural Resources <br />1313 Sherman Street, Room 423 <br />Denver, Colorado 80203=2273 <br />iii iiiiiiiiuiiiiii <br />SNOW MASS COAL COMPANY <br />Denver O7/rce. Suite 2300 <br />410 Seventeenth Sireel <br />Denver, Colorado 80202 <br />1303) 625-1966 <br />Mine Olltce. P.O.'Box 980 <br />Carbondale, Colorado 81623 <br />(303) 963J440 <br />RE: Snowmass Coal Company, Refuse Area Sedimentation Pond Redesign, <br />Permit No. 77-313 <br />Dear Bob: <br />The accompanying drawings illustrate the preliminary designs for two <br />types of sedimentation structures proposed for the refuse disposal area. <br />The earthen pond/dam design would significantly decrease the amount of ,--. <br />disturbance in the area adjacent to North Thompson Creek in comparison ~,• <br />to the currently approved Dravo design and would not require State <br />Engineer approval. <br />During the final stages of construction, the pond and embankment would <br />be studied by a qualified soils engineer to determine whether or not a <br />liner would be necessary for structural stability. <br />Either type of structure would be cleaned when the sediment volume reached <br />60% of the total sediment storage area. If the earthen pond type of <br />structure is selected for construction and it becomes necessary to install <br />a liner in the pond, I would like to note, at this time, that bentonite <br />would be the preferable lining material because it is less likely to be <br />damaged during cleaning and it could be maintained or repaired by on-site <br />personnel. <br />A steel tank type of structure would be cleaned by hoisting a small "Bobcat" <br />type of front-end loader into the tank. The loader would then be used to <br />push accumulated sediment into the cleaning sump. A drag-line bucket or <br />similar device would be used to remove the material from the sump. <br />You will note that we have not proposed any rip-rap along the toe of the <br />proposed embankment. This is the result of Dravo drawings entitled "Section <br />A and Section B, Proposed Embankment and Refuse Pond" which show that the <br />