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. ' i. IIIIIIIIIIII III • . Committee on ~ III I 999 Env)ronment cold Hill Town ~deetin~;, Inc'. Gold Hill, Colorado ~ heiq x~rxm September 23, 1997 Division of Minerals and Geology Department of Natural Resources 13 ] 3 Sherman St. , Room 215 Denver, Colorado 80203 Attn: MLRB Board Members Members of the Board: I'. U. Rox IG98 Moulder. C0803UG Page 1 of 12 pages The Gold Hill Committee on Mining and the Environment (COME), a duly constituted standing committee of the Gold Hi11 Town Meeting, lnc., being an interested party in matters pertaining to the Gold Hill Mill (Permit M-94-117), herein submits its comments in accordance with applicable Board regulations. Execative Summary: A reprise of the technical situation at the Gold Hill Mill, permit M-94- 117, is presented as it relates to the tailings pond spray evaporation system and associated freeboard and zero-discharge containmem issues. This is supplemented by an assessment of the regulatory and compliance background. Finally, four alternative responses are considered, with discussion of some imipfications of each choice. A recommendation is made to reclaim the site. Technical Summary: Problems with insufficient tailings pond containment volume were fast noted by DMG staff in June of 1994 ~ 1 J *. By August of that year, tailings spillage had occurred outtroard of the starter dam face )2J, stability of deposited tailings was in doubt )6J, and emplacement of additional tailings material had become questionable. An MSHA inspection of the site resulted in a report )3J suggesting that the available freeboard was not in accordance with good engineering pntctice, and recommending a minimum freelward during a design storm of at least three feet. The report also recommended enlargement of the existing two inch (2") decant line and widening of the da,n crest to at least nine feet (9'). DMG staff later established a requirement for four feet (4') of normal freeboard WSJ. Currently existing normal freeboard does not exceed twelve to fifteen int:hes (12' to 15"), COME estimate. In May of 1995, COM, Inc. proposed the addition of a two foot (2') high unlined berm on top of the existing dam )9J, but before this could be approved and implemented, overtopping of the liner occurred )lOJ due to heavy precipitation. In June 1995 DMG approved ~ 11, 15 J a two toot (2') temporary lift, apparently intended to supersede the tour toot requirement imposed in February. At about this same time )12J the Division approved an interim water management plan which allows oNy de minimis amounts of water in the Hazel A except during storms, during which the adit is intended to receive emergency overflows from tJrfe tailings pond if required to prevent dam overtopping. The Division took the position )14) that water contained in the Hazel A is process water, hence it cannot legally be discharged into the waters