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�Xj <br /> q- <br /> RlEivEs <br /> JUN 0 5 2018 <br /> DMSION OF RECLAMATIOM <br /> y Associates,k' And IN AND SAFETY <br /> June 3, 2018 <br /> Michael Cunningham <br /> Colorado Division of Reclamation, Mining and Safety <br /> 1313 Sherman St, Rm 215 <br /> Denver, CO 80203 <br /> RE: Fairplay Au Pit, M-1991-037,Technical Revision 08 Adequacy Response <br /> Mr. Cunningham: <br /> In response to your adequacy questions dated May 22, 2018, High Speed Mining, LLC has the <br /> following information to provide: <br /> 1. I hc' 01)er eltor has not I)1'01. (led suf f ciellt delall lbr the 1 h'W011 to evaluate the <br /> eftc'ctiveness of the proposed slornni,aler control,feature. The following i17fornialion <br /> mall he suhrllitted.• <br /> o. Provide he constructed at the base of <br /> the 111'er access road. <br /> The sump will have a surface area of 360 sq. ft. installed at the bottom of the road. It will be able <br /> to hold at least 660 CF of water. It will be at least five feet deep, with sideslopes of 1 H:1 V. Two <br /> foot tall containment berming along the downhill side of the river access road will provide <br /> freeboard. <br /> h. Provide the dimensions o f the area lrhich aril/drain to the srr1111). <br /> See the sizing calculations shown below. This area was delineated from aerial photography of <br /> the site. <br /> �. Proi•idc cnY calculations used to determine s'1'e of the sump. <br /> • Volume required =0.015 ac-ft(653 CF) of runoff <br /> 0 100-YR event=2.86 inches <br /> o Drainage area= 0.0.18 acres (area immediately uphill of the river access road that <br /> drains to the sump location) <br /> o Curve Number= 77 (Poor quality soils with forestation present) <br /> d. 111rr1tr•ate the surrll)on(r Plan AM/). <br /> Fairplay Au TR08 1 <br />