2008-07-13_REPORT - C1982056 - Laserfiche WebLink

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Northwest Colorado Consultant Geotechnicai / Environmental Engineering • Materials Testing July 10, 2008 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. has prepared this report outlining our observations made during the second quarter of 2008 at the Refuse Pile, which is located at Twentymile Coal Company's (TCC) Foidel Creek Mine in Routt County, Colorado. During this quarter, we visited the project site on June 30, 2008 to provide our quarterly inspection/observations. In addition, we visited the refuse pile on April 15 and May 21, 2008 to take compaction tests in Area 3. Six compaction tests (#374 to #379) were taken in Area 3 during these visits. All of the tests taken met the minimum compaction requirement of 90% of the maximum standard Proctor density. Copies of the compaction test results and the daily field report 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/AASHTO T99. At the time of our site visit on June 30, 2008, we completed site inspections of the pile. Based on our observations made during this visit, it appeared that the contractor was presently stockpiling the refuse coal in Areas 2, 2'h and 3 of the pile. The surface drainage conditions generally appeared to be adequate across the top and sides of the pile. 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 roadways throughout the pile were in much better shape than during our previous site visit in March. 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. We were advised that the old and new wash plants had produced approximately 108,300 tons of waste coal during the month of April 2008: 116,600 tons during May 2008: and approximately 115,400 tons during (970) 879-7888 • Fax (970) 879-7891 2580 Copper Ridge Drive • Steamboat Springs, CO 80487