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III IIIIIIIIIIIIIIII <br />999 <br />MINING <br />FOURTH QUARTER 2000 <br />ENGINEERING INSPECTION <br />EAST YARD AND WEST VALLEY FILL <br />GOB DISPOSAL PILES <br />The Sanborn Creek Mine approved permit document includes [he requirement [o inspect the coal <br />mine waste pile for stability quarterly. The inspection is to be perforned by a registered engineer <br />or other qualified professional specialist experienced in construction of earth and rockfill <br />embankments. <br />Daily inspections of [he 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 Yazd gob pile during 1999 <br />as 16,984 cubic yards. Compaction tests were performed on July 7, 1999, September 15, 1999, <br />November 10, 1999, December 9, 1999, and July 17, 2000 for the East Yard gob pile. Numerous <br />compactions tests were conducted during the critical fill operations of the toe area of the new West <br />Valley Fill. Gob material has consistently passed compaction tests. Compaction tests are required, <br />as necessary, based on the amount of material added to the waste area. Compaction tests are <br />planned as material is added to the waste area. <br />!Ut application for a Technical Revision was submitted [o [he 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 />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 are on file at the mine. Final preparation of the waste area was <br />completed during dre third quarter of 1998. The construction of the new waste area was monitored <br />on a daily basis, and inspected [he area during the critical construction periods specified by Rule <br />4.09.1(11). The West Valley Fill started receiving waste on July 27, 2000. Gob was placed in 6- <br />inch horizontal lifts with geotextile approximately every four foot. Compaction testing was <br />conducted approximately every four feet of lift and has consistently passed for the first phase of the <br />West Valley Fill. The West Valley Fill outslope on the first phase was seeded and covered with <br />erosion control bla~ilcets. <br />Thomas C. Anderson Date <br />Colorado Registered <br />Professional Engineer No. 14726 <br />3 7 3 7 Hwy 1 3 3 P O B o x 5 3 5 S o m e r s e t C o l o r a d o 8 1 4 3 4 U S A <br />TEL (9 7 0) 9 2 9- 5 1 2 2 FAX (9 7 0 ) 9 2 9- 5 1 7 7 <br />