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' -~- - <br />DEPARTMENT OF NATURAL RESOURCESD `~nVC ^^ III III III IIIIIII III <br />Harris D. Sherman. Executive Director g9g <br />MIlVED LAND RECLAMATION <br />723 Centennial Building, 1313 Sherman Street <br />Denver, Colorado 80203 Tel. (303) 839-3587 <br />Hamlet J. Barry, I I I, <br />Director <br />July 16, 1980 <br />TO: Rick Mi11s /~/j <br />FROM: Jim Pendleton \ _~•s- <br />RE: Certified Inspection ~ort for H-G Coal Company's <br />Hayden Gulch Minim-bisposal Plan <br />I have reviewed the certified inspection report for the Hayden Gulch <br />Mine of the H-G Coal Company, prepared by David D. Haas of Morrison- <br />Knudsen Company, Inc. I forward the following comments for your <br />consideration: <br />1) Any certified letter of inspection should be signed by the inspecting <br />professional, and should bear a facsimile of his professional seal. <br />The submitted report bears neither. <br />2) The Engineer, Mr. Haas (Colorado License PE #15932), is apparently <br />confused regarding the limitations of the interim regulations placed <br />upon excess spoil pile final slopes. He repeatedly refers to <br />"2.1v: lh: (360)" as the maximum allowable slope. The interim <br />regulations refer to 2.8v: 11i (36~) as the maximum allowable natural <br />slope on which an excess spoil pile can be placed. <br />3) The critical determination, as defined in permanent regulatory <br />section 30 CFR 816.71 (f), will be whether the fill achieves a long- <br />term static safety factor of 1.5. Mr. Haas states in section 1 of <br />his certified report that his preliminary examination indicates <br />that the long-term static safety factor exceeds the required 1.5. <br />When H-G Coal submits its permanent program application, it will <br />have to include a final stability analysis demonstrating that the <br />fill's slopes do attain the required long-term factors of safety <br />on 1.5 or greater. <br />4) The definition of "valley fill." contained in the interim and <br />permanent regulations differ. It will be necessary for H-G to <br />determine, to our satisfaction, whether this fill classifies as <br />a valley fill under the permanent regulations. If so, under <br />section 30 CFR 816.72, they would be required to place material in <br />horizontal lifts, not to exceed 4 feet in thickness, which they are <br />not, to my knowledge, currently doing. <br />