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<br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />DePUrtmem ui Natural Resources <br />I S I 1 Sherman 51 . Ronm 215 <br />Derner. Colorado dll `US <br />Phone: (3071 fl66-3567 <br />F.\t: 13011 d32-711 OG <br />DATE: <br />TO: <br />FROM <br />RE: <br />September 11, 1998 <br />Jim Pendleton <br />Joe Dudash ~ ~ D <br />~I <br />~I~~~ <br />DEPARTMENT OI <br />NATURAI. <br />RESOURCE:. <br />Roy Romer <br />Governor <br />lames 5. Lochhead <br />E.ecunve Dueaor <br />Michael B. Long <br />Division Direnor <br />Old Waste Pile, OSM Special Focus Oversight Inspection, Bowie l~to. 1 <br />Mine, Permit No. C-81-038, Bowie Resources Limited. <br />Larry Routten has asked me to request your geotechnical assistance in a matter involving <br />the Bowie No. 1 Mine. During the OSM 1997 Special Focus Oversight inspection of the <br />waste piles at the Bowie No. 1 Mine, OSM requested that the engineer's quarterly <br />inspection certification of the two waste piles at Bowie No. 1 state that the piles had been <br />constructed as designed. The West Ridge Waste Pile engineer's certification was <br />subsequently changed to reflect this wording. However, the old waste pile certification <br />wording has not been changed. There seems to be a reluctance on the part of Bowie No. 1 <br />to certify the old waste pile as having been constructed as designed since the pile <br />apparently has not been completely constructed according to the designs or to the <br />regulations. <br />I have noted five areas of concern for the old gob pile. First, the outslopes of the old <br />waste pile appear to be about 1.SH:1 V. Rule 4.09.2(6) requires the outslopes of a waste <br />pile to be 2H:1 V. Also, the permit application contains a commitment that the outslopes <br />will be at a 2H:1 V slope. Second, although not confirmed independently by the Division, <br />the soil cover is stated to be 15 inches to 24 inches in depth. Rule 4.10.4(5) requires 4 feet <br />of cover unless it is shown that the revegetation requirements can still be met with less <br />cover. I have not found any such demonstration, although the permit application is large <br />and somewhat disorganized. The permit application does have a commitment that 15 <br />inches to 24 inches of cover will be used. Third, a static factor of safety of 1.5 is required, <br />as stated in Rule 4.10.4(2). The permit application states two factors of safety, 2.15 and <br />1. l 1. However, it is not clear to me how these values were derived. The question of slope <br />stability came up during the oversight inspection. At the base of the old waste pile, <br />several trees were leaning over, although there were other trees in the area which were not <br />