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iii iiiiiiiiiiiiiiii <br />STATE Or COLORADO <br />(%(L~n"'•DIVISION OF MINERALS AND GEOLOGY <br />DeparlmeN of Natural Resour[es <br />1313 Sherman 51., Room 215 1 bo ~ • Nawt•2 : 97db <br />Dem~er, Colorado 80203 <br />Phone: (303) 866-3567 <br />FA%: (303) 832-8106 ~ / <br />December 23, 1999 v <br />Mr. Allan Cox <br />-f D' Homestake Mining Company <br />650 California Street <br />San Francisco, California 94108 <br />~.,.wA.n ~rvPrSrth /u S~ru czu{Q <br /> - DIVISION OF <br /> MINERALS <br /> <br /> GEOLOGY <br />_ _ <br />M\ ° ,~ ~~ r~' ~ <br />r <br />~ <br />~ <br />~ R E C L A M A T I O N <br />' <br />"" <br />` <br />' "' <br />- " MINING•SAF ETY <br /> <br /> <br />- <br />.. .. ,,,~/~~~ Bill Owens <br />Gorernor <br />J <br />,.n <br />l/l <br />Q <br />®d'= <br />~ <br />11 ` <br />r' <br />' GregE Watcher <br />, <br />• <br />..~• <br />r <br />~' <br />~~/' <br />~l' <br />-~- Executive Director <br />t <br />J Michael B. Long <br /> Dwivon Dvector <br />RE: Bulldog Mine, Permit No. M-77-215, Windy Gulch Assessment Report <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 />