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. III IIIIIIIIIIIII III <br />999 <br />~, U. S. Department of Labor <br />February 15, 1991 <br />~ ': <br />REC <br />File: SUB-C77 <br />Mine Safer/ and Health Administra uon <br />F 0. Box 25367 <br />Denver. Colorado 8G225-0367 <br />FEB 2 0 1991 <br />MEMORANDUM FOR WILLIAM E. HOLGATE <br />District Manager, District 9 <br />Coal Mine Safety and Health <br />Denver, Colorado <br />Mined Land <br />Reclamation Division <br />THROUGH: JOHN L. ODELL ~~~ <br />Chief, Mine Waste and Construction Division <br />Safety and Health Technology Center <br />,~~~ ~ <br />FROM: ST HEN W. DMYT W, P.E. <br />Civil Engineer, Mine Waste and Construction Division <br />SUBJECT: Sedimentation Control Dam, Seneca II Mine, Hayden, Colorado, <br />Peabody Coal Company <br />Berhan Keffelew, a reclamation specialist with the Colorado Mine Land Reclamation <br />Division (CMLRD), visited the office on February 14, 1991, to discuss a small dam at <br />the Seneca II Mine that was originally approved for construction by the State on July <br />16, 1986, with stipulations. The third and last stipulation was completed on July 17, <br />1989, and construction presumably followed at that time. More recently, a request for a <br />permit revision was received by the State on February 1, 1991. The February 1 <br />drawings presented by Mr. Keffelew indicate that the structure falls under MSHA <br />jurisdiction with regard to height and volume stored. At no time during this process <br />was MSHA informed of Peabody's intent to construct a dam on mine property. <br />Upon completion of the visit I telephoned Ron J. Gehrke, P.E., an engineer with <br />Peabody in Flagstaff, Arizona. I told Mr. Gehrke of my preliminary fmdings and <br />suggested that he forward design drawings and supporting documentation to the <br />District Office for evaluation. Since a portion of the reservoir is incised, I told Mr. <br />Gehrke to accurately exhibit the dam cross-section, facility plan view, and area-capacity <br />curve. Furthermore, engineering calculations should be included that demonstrate <br />emergency spillway suitability. In closing, Mr. Gehrke w•as advised to expect <br />enforcement activity. <br />During the discussion with dlr. Gehrke, I became aware that Peabody intends to <br />abandon the facility as a live dam. I pointed out abandonment regulation 77.216-~ <br />which precludes the ability of such a structure to impound water, sediment, or slurry. <br />