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~ III IIIIIIIIIIIII III ~ <br />_i1_ i <br />_ _~ <br />!1 .rte <br />~7 .~7 <br />~~ ~~~ <br />~~ ~~ <br />TUTTLE APPLEGATE RINDAHL, INC. <br />Consultants for Land and Resource Development <br />June 12, 1989 <br />i`. i°~~ <br />Mr. Michael J. Boyd, Reclamation Specialist <br />Mined Land Reclamation Division <br />215 Centennial Building <br />1313 Sherman Street <br />Denver, Colorado 80233-2273 <br />Re: File No. M-89-029, Distel Farm Resource <br />Deaz Mr. Boyd: <br />We have reviewed your adequacy letter regarding the Distel Farm <br />Resource and can provide you with the following information. Our <br />resFonses are numbered in correlation with your comments and <br />suggestions: <br />1. The mine site will be continuously dewatered for the life of <br />the mine. The pumping rates will vary depending on the time <br />of year, surface area of disturbance and the impact that <br />backfillinq and sloping shorelines has on sealing off the <br />aquifer. We would anticipate the dewatering to be an <br />intermittent basis only if groundwater flows into the pit <br />reduce substantially enough to allow for efficient operation <br />of the pump. Discharge rates from the pump could vary from <br />500 gpm to a maximum of 2,500 gpm. <br />The dewatering trench will consist of a 3 foot wide ditch <br />approximately 3 feet deep. A dewatering trench serves a <br />temporary use and as such generally has no side slope. The <br />trench is located in blue shale and can stand with vertical <br />walls with little maintenance. It will be located around <br />the perimeter of the mining phases and will be expanded as <br />mining progresses. Exhibit C has been revised showing the <br />location of the dewatering trench. A copy of the revised <br />plan is enclosed. <br />2. The relocation of the Coffin and Davis Ditch will not pose <br />any problems maintaining capacity to downstream users. C & <br />M Companies has a legal obligation to maintain flow to other <br />share holders as is common in any water right. The ditch <br />will have a gradient of 0.002 ft/ft. The channel cross <br />section will be 1.5 feet across the bottom with a depth <br />including freeboard of 2.0 feet. Side slopes on the ditch <br />will be maintained at 1:16. Decreed capacity is 17.3 cfs. <br />119~~0 Grant Street Suite 410 Denver, Colorado 80233 452-6611 <br />