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iiiiiiiiiiiiiiiiiii <br />_ -,._~. <br />FIRST QUARTER 2001 <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 constmction of earth <br />and rockfill embankments. <br />Daily inspections of the waste azeas 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 yards. Compaction tests were performed on July 7, 1999, September I5, 1999, <br />November 10, 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 area. 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 of the 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 />constmction of the West Valley Fill did not begin until 1998. Kiewit Western Company was <br />awarded the contract, and constmction was started during the second quarter of 1998. Photographs <br />of the underdrain were taken, and are on file at the mine. Final preparation of the waste azea was <br />completed during the third quarter of 1998. The construction of the new waste area was monitored <br />on a daily basis, and the area was inspected during the critical constmction 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 £II operations of the toe area. 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, the first phase. Compaction tests are planned as <br />material is added. •n~1 RFC <br />Inspected by: ~o_ <br />~W 3 <br />Under direction o£ ~ -~-;'_'_-_ <br />Colorado <br />~~ <br />~. <br />~t=w[s.,.,`' <br />3 7 3 7 Hwy 1 3 3 P O Box 5 3 5 <br />----- T E L (9 % 0) 9 2 9- 5 1 2 2 <br />Engineer No. 34286 <br />• Somerset C o l o r a d o 8 1 4 9 4 U S A <br />P A x (9 7 0 ) 9? 9 5 7 7 7 -- -~ - ~- - <br />