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'''l <br />~-.~ Cripple Creek & Victor Gold Mining Company <br />A Joinl Venture -Pikes Peak Mining Company, Manager <br />~Q ] Operations Ofllce <br />~/ P.O. Box 191, 2755 State Highway 67 <br />Victor, Colorado 80860 <br />(719) 689-2977 • FAX (719) 689-3254 <br />March 17, 1995 <br />Mr. Berhan Keffelew <br />Environmental Protection Specialist <br />Colorado Department of Natural Resources <br />Division of Mines and Geology <br />Office of Mined Land Reclamation <br />1313 Sherman Street, Room 215 <br />Denver, Colorado 80203 <br />Englewood Ottlce <br />5251 DTC Parkway. Suite 700, Englewood <br />Colorado 80111 <br />(303) 889-0700 • FAX (303) 889-0707 <br />RECFIVFC~ <br />~ z ~ 1995 <br />Division of Minerals ~ GeoW9Y <br />Reference: Cresson Project: Permit Number M-80-244: Response to Dr. David <br />Hvatt's Review of Cresson Project. <br />Dear Mr. Keffelew: <br />Thank you for the advance copy of Dr. Hyatt's review of the Cresson acid-base data and of <br />our proposals. It is the Cripple Creek & Victor Gold Mining Company's ("CC&V"'s) <br />conclusion, based on the review, that we performed appropriate analyses and made justifiable <br />conclusions with respect to the nature of the overburden at the Cresson Mine and with <br />respect to its handling. Any differences of opinion based on the analytical data and the site <br />are relatively minor. <br />Dr. Hyatt developed, in concert with the Office of Mined Land Reclamation, a list of topics <br />and directed his review to address these topics. It appears to CC&V that he found all of the <br />topics adequately addressed in the CC&V submissions provided to him. He found that the <br />chemical and geochemical data are consistent, of appropriate quality, and are appropriate <br />with respect to issues of acid generation and metals mobilization in overburden. More <br />specifically, he believes that the data are "well-presented" and that the presentation "focuses <br />on issues of likely acid generation and metals mobilization." Dr. Hyatt continues to state <br />"the authors present credible arguments for the relationship of these materials to <br />the...environment and to the likely reactions...during the post-depositional weathering." <br />Dr. Hyatt confirms the principal geochemical processes that CC&V has concluded direct the <br />weathering process, including the roles of jarosite, of basic carbonates, and aluminosilicates. <br />He adds that "if the reactive surface area or availability of these aluminosilicates is much <br />greater than that of the carbonate minerals, their neutralization reaction contribution lnay be <br />larger than simple comparisons of rate data would suggest. He also notes, just as has <br />CC&V, the role of the available surface area in both generating and neutralizing acid. He <br />terms the theoretical model of weathering and alteration "to be based on reasonable <br />projections of the chemistry set forth." He goes on to state "The proposed weathering <br />