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• • III IIIIIIIIIIIII111 <br />STATE OF CG~viwUO <br />DIVISION OF MINERALS AND GEOLOGY <br />Depanmem of ~Valurel Resources <br />7313 Sherman St., Room?75 D i v 1 5 I O N O F <br />Denver. ColcraCo 80203 <br />Phone UOA 866-3567 MINERAL S <br />F.4X. U03J 832-8106 --& <br />GEOLOGY <br />R E C L A M A T I O N <br />Date: November 1, 2000 M~NING~SAFETY <br />To : Gregg Squire, Cazl Mount "~"'''°e^° <br />c^~emo, <br />Greg E. watcher <br />From :Tom Schreiner ~S E.ecmr+e Oveuor <br />Michael B Long <br />D~~~~s~on Dueuor <br />RE : Mamm Creek Sand & Gravel Pit -Hydrologic Adequacy Review Comments <br />File No. M-2000-113 <br />I have reviewed the September 8, 2000 Regular 112 Application for the "Mamm Creek Sand & <br />Gravel Pit" located in Garfield County, 1.8 miles east of Rifle. along the Colorado River. The <br />applicant has requested a permit for 308.36 acres, most of which appear to occur within the <br />boundazies of the Colorado River channel. Portions of the affected ]and, such as the Renewable <br />Resource Area, occur within the active channel of the river. I recommend the following <br />adequacy concerns be addressed to the satisfaction of the Division prior to a recommendation of <br />approval. <br />RULE 6.4.4 EXHIBIT D -Mining Plan <br />1. As required by Rule 6.4.4(a), please clarify the method of mining to be employed in each stage <br />of the operation as related [o any surface disturbance ott affected ]ands, ie: wet mining or dry <br />mining with dewatering and offsite discharge. <br />2. As required by Rule 6.4.4{e)(i), please provide an estimate of the periods of time which wit] be <br />required for [he various stages or phases of the operation. (Please be as specific as possib]e in <br />providing the seasons or dates of the year when mining will occur for each of the various phases <br />to be ntined). <br />3. The applicant proposes a mine plan in which pit slopes will be excavated at 0.40H:1 V (near <br />vertical). Please explain how the desired 3:1 and 2:1 reclaimed slopes will be created underwater <br />in the absence of backfillin; when pit slopes are expected to be up to 25-30 feet in height. (It <br />appears that the pits will be allowed to fill in with water prior to backtilling to reclamation <br />contours. For example, the applicant states "when the West Property Line [o Horse Fence Area <br />is mined out, the pit is expected to fill with water."). The Division requests that the applicant <br />reevaluate the slopes to be created during mining and the feasibility of regrading such slopes to <br />the desired reclamation contours. The Division recommends the applicant consider maintaining <br />