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III IIIIIIIIillll III <br />999 <br />STATE OF COLORADO <br />Roy Romer, Governor <br />DEPARTMENT OF NATURAL RESOURCES <br />MINED LAND RECLAMATION DIVISION <br />DAVID C. SHELTON, Dlredor <br />MEMORANDUM <br />6 J ly 1987 <br />T0: Susan Mowry '~w~_~ <br />FROM: Jim Pendleton '~- ^-\\\ <br />RE: 1987 Quarterl aste Pi e $ Pond Inspection Report <br />I have review a portions of the above referenced report which deal with <br />the Refuse/Topsoil/Subsoil Piles at the Mt. Gunnison No. 1 Mine. The visual <br />and survey data verify that the piles are stable and properly maintained. I <br />personally examined the pile in June of this year: The pile did appear stable <br />and well drained. <br />My only derogatory comment regards the performance of compaction tests on the <br />waste pile. The operator reports: "It is estimated that about 5000 tons of <br />refuse was placed in the ist quarter. Refuse was placed in 24 inch or less <br />lifts and compacted with a caterpillar 815 self propelled sheepsfoot <br />compactor. Due to the small quantities no compaction tests were done during <br />the quarter. The material placed during the quarter visually appears to be <br />well compacted and should meet the specified 90% maximum dry density. The <br />area will be tested in following quarters." <br />If material is placed during a quarter, I believe that compaction testing <br />should be performed. The approved permit states that testing will be <br />performed, but does not specify a discrete frequency: In my personal opinion, <br />the pile should be tested at least quarterly. In order to avoid future <br />problems, I recommend that we require a more explicit statement from the <br />operator detailing the minimum frequency of testing to be performed. Testing <br />frequency could be tied to placement quantities, vertical lifts applied, or <br />any number of other parameters. The proposed testing frequency statement <br />should be prepared and submitted for our concurrence: Future quarterly <br />reports should present the results of compaction testing. <br />cc: Bob Liddle <br />423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203-2273 Tel. (303) 866-3567 <br />