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• • <br />STATE OF <br />iii iiiiiiiiiiiii iii <br />999 <br />COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1 313 Sherman 51., Room 215 <br />Denver, Color, do 80?03 <br />Phone: ~ 3071 866-3567 <br />FAS: 130]1 83'-8106 <br />DATE: November 26, 1998 <br />TO: Berhan Keffelew <br />FROM: Harry Posey ~~^~^k,~~ <br />RE: Findings, Amended; CCRVG, Cresson ermit, M-80-244 <br />CC&V's letter of November 24, 1998 provides information adequate to support their <br />interpretations about (1) the need for amendment addition to the Cresson waste rock to assure <br />reclamation success and (2) heap leach pad amendment rates to prevent acid mine drainage. <br />~~ <br />DEPARTMENT OF <br />NATURAL <br />RESOURCES <br />Ruy Rumer <br />Gorrrnur <br />)amee S Lochhead <br />Etecwive Director <br />Michael B. Long <br />Division Dmeao~ <br />Reclamation: The lime amendment rate, and the proposed 2-foot depth of amendment placement <br />are deemed adequate to protect the dominant root mass from adverse effects of acid generation in <br />most of the plant species proposed for reclamation. The additional bond is adequate to cover <br />cost of lime purchase and application to the waste rock covered areas. <br />Leach Pad Closure: The Division accepts and promotes the use of field tests as probably the <br />single most significant and representative measure of the probability of acid and/or dissolved <br />metals generation in spent ore and waste rock piles. The field test data furnished by the operator <br />on abandoned leach pads in [he region indeed show no significant acid development even after <br />several years after closure. Without acidic conditions, it can be assumed that dissolved metal <br />will not generally discharge. Thus, it is accepted that with the addition of the process levels of <br />lime to the ores, such conditions will be adequately protective of the heap leach pads into the <br />foreseeable future. The cost of such lime addition is part of the production costs and fto ore is <br />placed without lime addition, so there should be no additional bond requirements. <br />cc: Jim Dillie <br />Bruce Humphries <br />Jim Pendleton <br />Jim Stevens <br />