Laserfiche WebLink
~II'I~~I~II~~~~~ ~I~ <br />999 <br /> <br />STATE OF COLOlZADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman SL, Roam 215 <br />Denver, Colorado BO203 <br />Phone. 13031 8663567 <br />FAx: 003)832-8106 <br />March 17, 2000 <br />Mr. Mike Refer <br />CAMAS CO. Inc. <br />3605 S. Zeller St. <br />Lakewood, CO 80235 <br />RE: Final Review of Slope Stability Analysis for New I l2 Reclamation <br />Permit Application, Permit No. NM-99-098, Riverview Resources <br />Dear Mr. Refer, <br />DIVISION OF <br />MINERALS <br />GEOLOGY <br />REC LAM AiION <br />MINING•SAFETY <br />gill Owes <br />Governor <br />Greg E. Walther <br />Executive Director <br />Michael g. long <br />Division Director <br />This letter is being written to address the Division of Minerals and Geology's (DMG's) final review of [he Slope <br />Stability Analysis submitted March 9, 2000, for the new 112 application submi«ed by your company, Permit No. <br />#M-99-098, Riverview Resources Pit. On March 6, the Division included the following in our letter recommending <br />approval of [he application: <br />The setback of 200' from all structures must be observed, as specified under Rule 6.4.19, unless an adequate <br />engineering analysis is submitted to DMG no later than 4 p.m. Mazch 9, 2000. The setback from structures may be <br />determined by the Division to be less than 200' based upon such an engineering analysis. Should no analysis be <br />submitted [o DMG by the time and date specified, then the 200' setback must be maintained until such time as a <br />technical revision to the permit is submitted and approved by the Division. <br />Since the Division received the analysis within [he specified time period, we reviewed the submittal for the technical <br />adequacy of the factor-of-safety analysis for excavations at 20' and 42' depths. At a depth of 20', the proposed <br />setback of 40' proved to be adequate, yielding a factor of safety of I.OS, when measured from the toe o(the~ <br />excavated highwall. The 42' highwall excavation, however, required an 80' setback from the toe of the mined Face in <br />order to achieve an acceptable safety factor of 1.00. A written commitment to these setbacks fmm all swctures must <br />be submitted to DMG in order for us to change the currently accepted setback of 200'. Should the Operator mine any <br />deeper than 42 fee[, a 2H:1 V length of setback will be required from the toe of [he mine face. <br />Please confirm your acceptance of these setbacks in writing prior to the Board Hearing on March 22, 2000. [f this is <br />not done prior to the Board Hearing, the setbacks for the swctures inside and adjacent to the permit area revers to <br />the previously agreed-upon 200 foot setback. <br />If you have any futther questions, please feel free to contact me at (303) 866-3567. <br />Sincerely, <br />C~tina L. Kamnikar <br />Environmental Protection Specialist <br />Cc: Cazl B. Mount, DMG <br />Shani Eastin, Tuttle-Applegate Inc. <br />Connie Davis, CAMAS <br />US Fish & Wildlife Service <br />US Army Corps of Engineers <br />Objection List <br />