2012-04-10_REPORT - C1981018 - Laserfiche WebLink

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t Colorado Consultants Geotechnical f Environmental Engineering • Materials Testing April 9, 2012 Twentymile Coal Company 29515 RCR #27 Oak Creek, CO 80467 Attn: Mr. Jerry Nettleton Job Number: 99 -3983 Subject: Quarterly Observation Report, Refuse Pile, Foidel Creek Mine, Routt County, Colorado. Mr. Nettleton, As requested, NWCC, Inc. (NWCC) has prepared this report outlining our observations made during the first quarter of 2012 at the Refuse Pile located at Twentymile Coal Company's (TCC) Foidel Creek Mine in Routt County, Colorado. During this quarter, Tim Travis of NWCC visited the project site on March 30, 2012 to provide the quarterly inspection/observations of the Refuse Pile. In addition, a representative of NWCC visited the refuse pile on March 28, 2012 to take compaction tests in the new Expansion Area of the refuse pile. A total of four compaction tests ( #485 to #488) were taken in Expansion Area during this quarter. All of the tests taken during this quarter met the minimum compaction requirement of 90% of the maximum standard Proctor density. Copies of the compaction test results and the daily field reports are attached. It should be noted that the abbreviations given in the Nuclear Density Test Results (Proctor Data) are as follows: Maximum DD = Maximum Dry Density and OMC = Optimum Moisture Content. Both of these values have been determined in accordance with ASTM D698. At the time of our site visit oil March 30, 2012, we completed a cursory site inspection of the existing refuse pile. Based on our observations made during this visit, it appeared that the contractor was presently stockpiling and compacting the refirse coal in the new Expansion Area. It should be noted that at the time of our visit, we did not observe any signs of instability, structural weakness or hazardous conditions at the pile. It should also be noted that the internal roadways in the new expansion area of the pile were in good condition. The upper haul road to Areas 2, 3 and 4 of the refuse pile was also in good condition. As suggested, the water levels in the monitor wells installed on October 23, 1997 and December 9, 1999 were measured during this quarter on a monthly basis. A table and graphs showing the monthly water levels are attached. As noted in our previous report, the water level in Monitor Well N increased significantly fi•om readings on April 8, 2011 and May 10, 2011. The water level went from 32.04 feet to (970) 879 -7888 • Fax (970) 879 -7891 2580 Copper Ridge Drive • Steamboat Springs, CO 80487