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DIVISION OF RECLAMATION, MINING AND SAFETY Department of Natural Resources 1313 Sherman St., Room 215 Denver, Colorado 80203 Phone: (303) 866 -3567 FAX: (303) 832 -8106 To: Russ Means From: Tim Cazier, P.E. Date: August 22, 2011 Re: JD -8 Mine Drainage Design Plan — General Stormwater Comments, Permit No. M- 1984 -014 / AM -01 The Division of Reclamation, Mining and Safety (DRMS) engineering staff has reviewed the June 1, 2011 Attachment A Drainage Design Plan for the JD -8 Mine EPP Stormwater Management Plan prepared by Whetstone Associates, Inc. The following comments are posed to ensure adequate engineering analyses and design practices are implemented to eliminate or reduce to the extent practical the disturbance to the hydrologic balance expected by the mining operation with respect to water quality and quantity in accordance with Rules 3.1.6(1) and 6.4.21(10). 1. Page 1 and Figure 1 — Existing Drainage. Run off from non - contributing drainage area N -A appears to report to the west side of area N -B where runoff from both areas would report to the low spot in the access road (approximate elevation 6,760), with the only outlet being to discharge across the road and report to the low spot (approximate elevation 6,720) on the road below (forming the boundary of area N -C). Runoff reporting there would presumably report to yet another low spot (approximate elevation 6,580) on the road forming the boundary of area N -E. There does not appear to be another road borrow ditch downgradient of the area N -E boundary to divert runoff away from the permit area. Please provide discussion on available storage at the aforementioned low spots and the capacity to store the required 10 -year, 24 -hour storm runoff (pursuant to the DRMS 2008 inspection report, included in the reference section) or provide further detail as to how this non - contact runoff is diverted away from the affected area. a. Also note the drainage system is required to pass or convey the runoff from the 100 - year, 24 -hour storm. As such, stormwater channels in the permit area must be able to convey the peak flows resulting from the 100 -year event not stored as part of the 10 -year storage capacity. It may be easier to demonstrate the capacity to divert the entire 100 -year peak flow. Office of Mined Land Reclamation MEMORANDUM STATE OF COLORADO COLORADO D I V I S I O N O F RECLAMATION MINING —&— SAFETY John W. Hickenlooper Governor Mike King Executive Director .Loretta Pineda Director Office of Denver • Grand Junction • Durango Active and Inactive Mines