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n <br />u <br />- 999 <br />DIVISION OF MINERALS AND GEOLOGY <br />Department o(Natural Resources <br />1313 Sherman 8t.. Room 215 <br />Denver, Colorado 80203 <br />Phone: 1303) 866-3567 <br />FAX: 1303) 832 8106 <br />December 23, 1999 <br />Mr. Allan Cox <br />STATE OF <br />COLORADO <br />DIVISION OF <br />MINERALS <br />GEOLOGY <br />RECLAMATION <br />MIN ING•SAFETY <br /> <br />Homestake Mining Company Bil I Owens <br />covemor <br />650 California Street Greg E. bValcher <br />San Francisco, California 94108 EsecW rve DireUOr <br /> Michael B. Long <br /> <br />RE: Bulldog Mine, Permit No. M-77-215, Windy Gulch Assessment Report Diva Sion Dneclor <br />Dear Mr. Cox: <br />Upon review of the Windy Gulch Assessment Report dated December 1999 and our subsequent <br />conference regarding the same, the Division encourages Homestake to submit the proposed <br />(verbally) technical revision addressing installation of bypass structures to intercept Windy Gulch <br />surface water flow and carry it past the Bulldog Mine's 9360 and 9700 Level waste rock dumps. <br />The revision should also include plans to address protection of the quality of surface water and <br />groundwater resources from acid and metals loading potentially occurring through weathering of <br />rock, noted on the 9700 Level dump, that contains leachable minerals such as iron sulfides. <br />Installation of adequate diversion structures will resolve the problem, noted in the Division's June <br />9, 1999 inspection report, regarding the apparent lack of a 9700 level waste rock dump water <br />diversion. If the revision includes adequate provisions to address protection of water quality from <br />the degradation potential of the leachable minerals occurring in the dump, then that problem, also <br />noted in the Division's June 9, 1999 inspection report, will be resolved. <br />The Division will review the proposed diversion plan for content regarding construction and design <br />specifications. Particular attention will be paid to how effective the structures will be in <br />intercepting the surface water flow and isolating it from the waste rock dump material. <br />If you need additional information, please contact me at the Division of Minerals and Geology, <br />Durango Field Office, 701 Camino Del Rio, Room 125, Durango, Colorado 81301, telephone no. <br />970-247-5062. <br />Sincerely, <br />/// ~ ~ , . <br />Steve S. Shuey <br />Environmental Protecti Specialist <br />cc: Allen Sorenson -DMG <br />Harry Posey -DMG <br />Jerry Rowe -Water Management Consultants <br />