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^ !~/~ • • III III III III IIII III 999 Cyorus Orcnard Valley Mine y j ` ~~ ~ P. 0. Bos 1299 Paonia. CO 8742& ~; Pnone: 303527-4135 Orchard Valley Fax: 303-527-223a Yip. -. " . February 7, 1990 rFB ~ ~ 1`3q~ MINED L4R~ ''CC=AMATION DIVIS;CU Mr. Jeff Clapton Colorado Mined Land Reclamation Division 1313 Sherman Street Denver, CO 80203 RE: REPAIR OF WEST PORTAL CUT; MINOR REVISION 62, C83-038 Dear Mr. Clapton: Cyprus Orchard Valley Coal Corporation received approval on June 9, 1989, to affect repairs to the slide that occurred north of the West Mine portal yard. The topsoil pile was moved to the extent possible, beginning July 15, 1989. The slide face was inspected by Mr. Michael Bukovansky of CH2M Hill during the week of July 17, 1989. By making trench cuts in the bench below the topsoil pile, it was determined the slide did not extend further into the bank than was observed on the surface. The drainage around the stock- pile was stabilized, and the area of the slide was left to be re- moved in conjunction with work on the West Ridge Waste Pile. The progress on the West Ridge Waste Pile allowed for the cut on the slide area to be started on November 7, and was completed on aROroximatelY November 18. Subsequent measurements of the new cut slopes reveal they do not conform to the recommended profile (sheet 2 of 4) from CH2M H1 1, submitted with MR62. The actual topsoil stockpile slope is 2.2'H:1'V; the recommended slope is 2 1/2'H:1'V. The bench below the topsoil stockpile is 13.5' wide, counting ditch width; l0' was the recommended width. The actual cut slope (where the slide was) is 1.73'H:1'V: the recommended slope was 2'H:1'V. The bench (remaining after the cut was complete) was 15'6" wide; 15' was recommended. This cross sec- tion is in the middle of the slide area affected. Because the area in question is of a limited size, any wort, to con- form to the recommended slopes would recruire substantial amounts of material being moved to remote locations. I have asked Mr. Bukavonski to review the work that has been done and provide us with his professional opinion. The area of the slide had been underlined by what appeared to be a clay slip zone. This zone has been removed by the new face cut.