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/ i -.. , <br />• • <br />STATE OF COLORADO <br />Roy Romer, Gove <br />DEPARTMENT--OF NA;URAL RESOURCES <br />MINED LAND RECLAMATION DIVISION <br />FRED R. BANTA, Dlnetor <br />March 30 , 1989 <br />Mr. Dennis Conn <br />P.0. Box 591 <br />Somerset, Colorado 81434 <br />RE: Lower Waste Pile Compaction and Stability Report and Semi-annual <br />Subsidence Monitoring Data Report; Mt Gunnison Mine No. 1, C-80-007 <br />Dear Mr. Conn: <br />The Division has reviewed the letter report submitted by West Elk Coal Company <br />for the required quarterly monitoring of compaction and facial slope stability <br />of its lower waste pile at the Mt. Gunnison No. 1 underground coal mine. The <br />compaction monitoring report documents that a portion of a recent lift of <br />material placed on the pile was determined to be insufficiently compacted when <br />tested on October 10th. This portion of the upper lift was subsequently <br />recampacted and retested the following day. The October 11th fasts determined <br />the upper lift to be in compliance. <br />The semi-annual subsidence monitoring data report received December 23, 1988 <br />was also reviewed and found to be well done and in compliance. This report <br />documents that residual subsidence is continuing to occur above conventional <br />panels 1W1S and 1W2S. Extraction was completed in panel 1M1S in February of <br />1987 and 1n panel 1W2S in October of 1981. The rate of subsidence has <br />decreased slightly during each subsequent six month monitoring period. All of <br />this is in keeping with ch aracteristic ground subsidence experience in <br />Colorado. <br />215 Centennial Building, 1313 Sherman Street Denver, Colorado 80203.2273 Tel. (303) 868.3587 <br />