2009-04-08_REPORT - C1982056 - Laserfiche WebLink

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Geotechnical I Environmental Engineering - Materials Testing April 7, 2009 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 first quarter of 2009 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 March 30, 2009 to provide our quarterly inspection/observations. In addition, we visited the refuse pile on January 30, February 20 and March 5, 2009 to take compaction tests in Areas 3 and 4. Six compaction tests (9402 to #407) were taken in Area 4 and three compaction tests (#408 to #410) 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. At the time of our site visit on March 30, 2009, we completed a cursory site inspection of the pile. Based on our observations made during this visit, it appeared that the contractor was presently stockpiling the refuse coal in Area 4 of the pile. We also observed that the soil cover materials had been placed over the waste coal along the north side of Area 1 since our previous inspection in December 2008. 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 be noted that the majority of the pile was covered with 2 to 4 inches of snow at the time of our site visit, with the exception of the portion of Area 4 in which the refuse coal was being stockpiled. It should also be noted that the roadways throughout the pile were severely rutted and a considerable amount of runoff was flowing down the ruts in the roadway surface. 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. It should be noted that well 4MW was damaged/buried during movement of topsoil on (970) 879-7888 • Fax (970) 879-7891 2580 Copper Ridge Drive - Steamboat Springs, CO 80487