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rado t.onsuitants Geotechnical /Environmental Engineering • Materials RECEI!!E® January 6, 2003 ~AN O ~ 2~~4 Twentymile Coal Company 29515 RCR #27 Division of Pdinerals and Geolog~~ Oak Creek, CO 80467 Attn: Mr. Rick Mills Job Number: 99-3983 Subject: Quarterly Observation Report, Refuse Pile, Foidel Creek Mine, Routt County, Colorado. Ladies & Gentlemen; As requested, NWCC, Inc. (Northwest Colorado Consultants, Inc.) has prepared this letter outlining our observations made during the fourth quarter of 2003 at the Refuse Pile, which is located at the Foidel Creek Mine in Routt County, Colorado. During this quarter, we visited [he project site on October l3 and December 30, 2003 to provide our quarterly observations. Our firm also visited [he subject site three times during this quarter to test the compaction of the refuse materials that had been placed and compacted. At the time of our site visit on October 3, 2003, we took three (3) compaction tests (#248 to #2S0) across Area 2'/, of the refuse pile. All of the tests taken met the minimum compaction requirement of 90°/n of the maximum standard Proctor density. We visited the site a second time during this quarter on November 12, 2003 to test the compaction of the materials being placed in [he refuse pile. During this visit we took five (S) compaction tests (#251 to #255) on [he fill materials that had been placed in Area 2. All of [he tests taken met the minimum compaction requirement of 90% of [he maximum standard Proctor density. We visited the project site a third time during this quarter on December 3, 2003, to test the compaction of [he fill materials being placed in Area 1. During this visit we took four (4) compaction tests. 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 daily field reports are attached. I[ should be noted that the abbreviations given in the Nuclear Density Test Results (Proctor Da[a) 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. We also visited the site on October 13, 2003 to observe the excavation and placement of the coarse fill materials along the toe of the fill slope at the extreme northern end of Area 1. The coarser fill materials were placed in the toe of the pile to help direct/divert the seepage coming the face of the pile away from the toe of the slope, which in turn will increase the stability of the pile. At the time of our visit, the contractor had removed and replaced a considerable amount of the soft and wet fill materials that were located at the toe of [he refuse pile (north face of Area 1). It appeared that the soft and saturated fill materials were replaced with a coarser refuse material that was relatively free of fines. We also understand that the coarser (970) 879-7888 • Fax (970) 879-7897 • nwccl Qmindspring.com 2580 Copper Ridge Drive • P.O. Box 775226 • Steamboat Springs, CO 80477