PERMFILE122331 - Laserfiche WebLink

Home Browse Search

our permit application. Our map MLR-1 shows the existence of a small draining channel into the area in which we propose to construct the tailings disposal site. This drainage has in the past only exhibited light flows of water during rapid snow melt conditions or during heavy rains. It is itself probably the result of a naturally occurring 25-year, 24-hour storm since no evidence exists that it may have been manmade. Our proposed rechanneling of this drainage is shown on the Mill Site Reclamation Plan, Map - MLR-3. This area is geologically defined as old lake beds. It is well described in U.S.G.S. Professional Paper 148 by Emmons, Irving & Laughlin, 1927. Our proposed tailings disposal area is underlain by thick lenses of highly impervious silty clay with enclosed, thin, dense sand beds with occasional pebbles. Communication with the Colorado State Engineers, Ground Water Section, indicates the first known aquifer in this area to be 80 to 100 feet below surface. This data is based on well logs of the nearest water wells to our mill site. C. The only geochemical testing data known to us is what has been provided in the report by CTL/Thompson, Inc. We have no objection to collecting a tails sample and a decant solution and having them analyzed for acid base potential, pH, Pb, Zn, Cu, Cd, As, N, Ag, A1, and Mn as requested in your letter of May 29, 1990. D. Since the permeability rates described in the CTL/Thompson, Inc. report indicate the determined permeability rates over the majority of the proposed tailings disposal site to be as low as 2 to 7 feet per year, we do not think a synthetic liner to be necessary. Some discretion is warranted regarding our proposed excavation of the material to be used for the tailings impoundment dam in order that areas less impervious remain unexcavated. Compaction recommendations as recommended by the CTL/Thompson, Inc. report are intended to be followed if necessary. E. 8 F. Our mill site property is shown on the copy of a portion of the Leadville South Quadrangle Map - Scale 1:24000, 1969 issue, found in Exhibit E of our original application. This data indicates our property to be slightly over three miles from the Yak Tunnel. The California Gulch Drainage is approximately, at its closest point, about 1000 ft. from the nearest part of our tailings disposal area as proposed, and at an elevation of about 20 ft, lower.