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~_~ <br />CTL/THOMPSON, INC. <br />• CONSULTING GEOTECHNICAL AND MATERIALS ENGINEERS <br />August 12, 1981 <br />Empire Energy Corporation <br />5900 South Yosemite Street <br />Suite 160 <br />Englewood, Colorado 80112 <br />Attention: Mr. Rick Mills <br />Subject: Revised Construction Plans <br />Coal Processing Waste Bank <br />Empire Energy Mines No. 5 and <br />Craig, Colorado <br />Job No. 7372 <br />Gentlemen: <br />We have revised construction plans for a coal Processing Waste Bank to <br />be constructed at Empire Energy Mines No. 5 and 9 near Craig, <br />Colorado. Construction revisions were necessary due to a variance <br />between actual field conditions and large scale topography used for <br />initial design. The coal processing waste bank construction revisions <br />were done to meet performance standards specifications of Section 4.10 <br />of the Colorado Mined Land Reclamation Board. <br />The bank is to be constructed near the top of a local hill within the <br />permit boundary. Topographic maps indicate that slopes in the area of <br />planned construction are generally less than 6:1 (horizontal to verti- <br />caT). Most of the area surrounding the waste bank slopes downward away <br />from the bank at relatively gentle grades. The site was previously used <br />as a gravel source by the County for maintenance of roads. The material <br />was developed from a conglomerate formation and excavated in an erratic <br />pattern. Apparantly, when highly cemented material was encountered, the <br />excavation operation was shifted to other areas of the pit. This re- <br />sulted in a very uneven surface. Our original design was based up <br />topography that did not truly reflect the local variations of the sur- <br />face. As part of this design, new mapping was obtained by cross sec- <br />tions in the proposed construction area. Additional test pits were <br />excavated to evaluate the surficial deposit. With this additional data, <br />the proposed pile design was revised to more accurately reflect field <br />conditions. Haul roads are present west and south of the planned con- <br />struction area. <br />• Surface diversion ditches have been designed around the perimeter of the <br />toe of the bank to intercept surface runoff from the pile in accordance <br />~. with 4.10.3(2). The surface diversion ditches will convey water col- <br />lected to surface ditch HR-D4 and eventually to sedimentation pond HR-P1 <br />~.... .~... ~ ..c.~,.co rani Hoorn ononn ono, eaa m~~ <br />