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iii iiiiiiiiiiiiiiii <br />~~;, <br />FOURTH QUARTER 2000 <br />ENGINEERING INSPECTION <br />EAST YARD AND WEST VALLEY FILL <br />GOB DISPOSAL PILES <br />The approved Sanborn Creek Mine permit document includes a requirement for quarterly <br />inspections of coal mine waste piles for stability. The inspection is to be performed by a registered <br />engineer or other qualified professional specialist, who is experienced in the construction of earth <br />and rockfill embankments. <br />Daily inspections of the waste areas are conducted during fill operations. Safety berms are required <br />on the downhill edge of the pile by the Mine Safety and Health Administration. <br />Surveyor John Menke reported the volume of material placed in the East Yard gob pile during 1999 <br />as 16,984 cubic yazds. Compaction tests were performed on July 7, 1999, September 15, 1999, <br />November ] 0, 1999, December 9, 1999, and July 17; 2000 for the East Yard gob pile. Compaction <br />tests are required, as necessary, based on the amount of material added to the waste azea. As of <br />December 31, 2000, the East Yard gob pile has reached its maximum design capacity, and no more <br />material will be placed on the pile. <br />An application for a Technical Revision was submitted to the Division for a new coal refuse and <br />mine development waste area. The new area is located to the west ofthe facilities area, and is <br />known as the West Valley Fill. Technical Revision Number 29 was approved in 1997, but due to <br />the timing of the approval, and the necessary requirements to put a contract in place for the work, <br />construction of the West Valley Fill did not begin until 1998. Kiewit Western Company was <br />awarded the contract, and construction was started during the second quarter of 1998. Photographs <br />of the underdrain were taken, and aze on file at the mine. Final prepazation of the waste azea was <br />completed during the third quarter of 1998. The construction of the new waste azea was monitored <br />on a daily basis, and the azea was inspected during the critical construction periods specified by Rule <br />4.09.1(11). The West Valley Fill started receiving material on July 27, 2000. Numerous <br />compaction tests were conducted during the critical fill operations of the toe azea. Material was <br />placed in 6-inch horizontal lifts, with geotextile fabric placed approximately every four feet. <br />Compaction testing was conducted approximately every four feet of lift and consistently passed <br />during the first phase of the West Valley Fill. The West Valley Fill outslope was also seeded and <br />covered with erosion control blankets, during_the first phase. Compaction tests are planned as <br />material is added. `p,~,fJ^ HFG.7Sr_ <br />Inspected by: <br />Under direction of: <br />Colorado Re'~q~~,¢,~$rp'l~(onal Engineer No. 34286 <br />3 7 3 7 Hwy 1 3 3 r' U B n c 5 3 5 S o m e ~ s r t C o l o r a d o 8 1 4 3 4 U S A <br />TEL (970i 029-5122 FAX (970)929-5177----~ --~-- _~ <br />