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III IIIIIIIIIIIII III 999 DIVISION OF MINERALS AND GEOLOGY Depanmenl of Nalunal Resources 1 ; I {Sherman $I ,Room ?15 Dcnvrr. Colorado NU201 Phorn•'. 1311 S) ribb-3567 f,\X: l {rl f) Y,it-711 U6 DATE: November 20, 1997 STATE OF COLORADO ~I ..' ~~~ DEPARTMENT OF NATURAL RESOURCES ftn. Ramer Gm~rnnr lames S. Lw hhead TO: Bob Oswald ^ e~r~~l~~r olrrJn~ ' / Ahsharl ft. Lnnl; ~ / / D~s'won Dimour FROM: Harry Posey~l't/'i! J RE: Comments on Au Mining, Inc., Golden Wonder Mine, Lake City, CO, Permit No. M-78-091 Enclosed is a copy of Lance Barker's letter to me (undated) received Nov l4 regarding recent communications with CDH and EPA and results of water sampling. (As we discussed this morning, I will continue to encourage Mr. Barker to route cotrespondence through you to ensure consistency of voice in your management of this permit.) This memo recalls a site visit this summer, and examines the chemical analyses famished by Mr. Barker. At the time of my visit to the Golden Wonder mine this summer, the portal discharge (about 2 gpm) was routed across the waste rock pile where it seeped into the pile on the outslope. Also at that time upper Deadman Gulch was routed to a sump which presumably focused that water into the ground, probably along the waste/alluvium boundary. Some water from upper Deadman appeazed to have traversed the edge of the waste rock during high flow. The most recent waste rock on the dump appeared to be pyrite-rich, high-clay rock consistent with that from an azgillic or advanced azgillic alteration zone where there is generally no cazbonate buffering capacity and from which highly acidic water develops. The flowing water was cleaz, which indicated to me it was probably of extremely low pH. Mr. Barker had just taken over the permit t that time, and I do not believe he had begun physical excavations. He did have equipment on site, some of which (believe he had retrieved from underground. [n our discussions at the site, I explained how the Division tends to view groundwater conditions at sites where there is previous disturbance. In that regazd, we discussed ways to comply with the groundwater regulations. f suggested that groundwater quality might be improved if the portal discharge water could be routed into the ground, along the toe of the high wall, thus reducing acid generation metals release. We discussed ways of creating infiltration either to the left or to the right of the portal. By forcing the water to infiltrate along the high wall base, the preferential flow should be along the waste/alluvium contact, and the water would come in contact with less of the waste rock. If permeability of the alluvium was actually lower than the waste rock, flow would tend toward the alluvium and away from the waste. Given that the waste appeared to be clay rich, the latter condition seemed a likely possibility.