2008-10-06_REPORT - C1982056 (2)

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V I 'k - e---m(2) , rado Consultants. Inc. Geotechnical ! Environmental Engineering • Materials Testing RECEIVED OCT 0 O 2008 Subject: Quarterly Observation Report, Refuse Pile, Foidel Creek Mine, Routt County, Colorado. Mr. Nettleton, Division OT Reclamation, October 2, 2008 Mining and Safety Twentymile Coal Company 29515 RCR #27 Oak Creek, CO 80467 Attn: Mr. Jerry Nettleton Job Number: 99-3983 As requested, NWCC, Inc. has prepared this report outlining our observations made during the third 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 September 26, 2008 to provide our quarterly inspection/observations. In addition, we visited the refuse pile on July 3, July 29, August 12 and September 23, 2008 to take compaction tests in Areas 2, 21/z, 3 and 31/z. Sixteen compaction tests (#380 to #395) were taken in these Areas during our site 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 September 26, 2008, we completed site inspections of the pile. Based on our observations made during this visit, it appeared that the contractor had graded these areas so that they were now at similar elevations and grades so that Areas 2, 2 1h, 3 and 3'/z were now one uniform bench. In addition, we observed that the contractor was mixing and blending the saturated "cake" product coming from the old wash plant with the coarser grained materials coming from the new wash plant. 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. 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. (970) 879-7888 • Fax (970) 879-7891 2580 Copper Ridge Drive • Steamboat Spfings, CO 80487