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STATE OF COLORADO <br /> DIVISION OF MINERALS AND GEOLOGY <br /> Department of Natural Resources ��of,C <br /> 1313 Sherman St.,Room 215 He o <br /> Denver,CO 80203 <br /> Phone:(303)866-3567 *lE76« <br /> FAX:(303)832-8106 <br /> Roy Romer <br /> Governor <br /> Michael B.Long <br /> DATE: June 28, 1993 Division Director <br /> TO: Steve Renner <br /> FROM: Jim Pendleton - <br /> RE: Old Coal 5ePile - Mid-Continent Resources, <br /> Coal Basin Mine (Permit #C-81-017) <br /> In response to your request, I accompanied Tony Waldron on an <br /> examination of the old coal refuse pile at the Coal Basin Mines on <br /> Tuesday, June 22, 1993 . We examined two specific areas; the <br /> incised portion of Dutch Creek at the toe of the terrace slope <br /> above which the refuse pile is founded, and the seep area at the <br /> northwest end of the refuse pile. Neither appears to represent an <br /> immediate threat to the stability of the structure, but both should <br /> receive expeditious treatment to avoid the development of a more <br /> critical problem. <br /> Dutch Creek Incision <br /> The old refuse pile is founded on an erosional terrace situated <br /> approximately 80 to 100 feet above the modern valley floor of Dutch <br /> Creek. Adjacent to the upper, northwestern end of the old coal <br /> refuse pile, Dutch Creek is actively incising the Mancos Shale <br /> slope which forms the bedrock slope of the terrace. The incision <br /> wound is approximately 200 feet in length and has migrated upslope <br /> to the terrace surface approximately 80 feet above the channel . <br /> The crest of the slope appears to have receded approximately 10 <br /> feet in the past decade. It has approached to within 25 feet of <br /> the toe of the coal refuse pile. The Shale and colluvial material <br /> is well consolidated and stands at approximately 80 degrees from <br /> horizontal. I could not discern any evidence of mechanical failure <br /> in the pile or its foundational slope. <br /> Coal Basin is a nationally-renowned location for the occurrence of <br /> debris flows. High precipitation spring and early summer events <br /> cause the liquefaction of spring melt saturated, poorly-sorted <br /> colluvial deposits. The Mid-Continent Resources bath house was <br />