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1 s°i�" N TED ZORICH&ASSOCIATES,INC. DENVER caLOPACoeoDOTZACONSULTING <br /> ENGINEERS IN WATER RESOURCES (303)7770554 <br /> September 26 , 1985 <br /> Mr. Mark Steen <br /> 1 Gold Hill ventures Limited SEP 2 b 19b <br /> Partnership <br /> Post Office Box 1523 MINED LAND <br /> Longmont, Colorado 80501 RECLAMATION DIVISION <br /> 1 Re: Capacity of Interim Ditches and <br /> Freeboard for the Tailings Pond <br /> 1 Dear Mr. Steen: <br /> As you requested, Ted Zorich and Associates , Inc. (TZA) <br /> 1 has estimated the required carrying capacity of the interim <br /> ditches associated with the tailings pond , and the freeboard <br /> required for the tailings pond dikes. The purpose of these <br /> precautions is to insure that low quality water does not enter <br /> the surrounding environment. <br /> As you discussed, the tailings pond to be constructed will <br /> 1 have a 400 foot long dike and will extend 260 feet uo slope <br /> from the dike. Permanent ditches will be installed initially <br /> to divert surface runoff around the 260 by 400 foot area. The <br /> ' portion of the 260 by 400 foot area that is used will increase <br /> with time. The 400 foot dike will be constructed initially and <br /> the initial active area of the tailings pond will extend up <br /> ' slope 50 feet. <br /> The interim ditch will be located just over 50 feet un <br /> slope from the dike and will collect surface water runoff that <br /> 1 occurs below the permanent drainage ditches and within the 400 <br /> by 260 foot area, and carry this water off the tailings pond <br /> area . As you stated, the distance uD slope from the dike will <br /> 1 increase from 50 feet to 100 feet, then to 200 feet before <br /> being extended to 260 feet. Interim ditches are planned to be <br /> constructed each time the pond is expanded except when it is <br /> expanded to the full 260 feet. The estimated drainage areas <br /> ' and maximum runoff rates are given on the attached table. <br /> TZA' s recommended freeboard distance for the tailings pond <br /> 1 dikes is 0 . 5 feet . The 100 year, 24 hour storm is 4 . 6 inches <br /> 1 <br />