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STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural kesources - <br />1313 Sherman St., Room 215 C O L D RA D O <br />Denver, Colorado 80203 DIVISION O F <br /> Rte L $ <br />~ I4t I N <br />Phone: (303) 8663567 S <br />FAX: (303) 832$106 G E O L O G-Y <br /> 0.E CLANATION•NINING <br />' SAFETY•SCIENCE~ <br />March I1, 2004 <br /> Bill Owens <br />Mr. Forrest LUke Governor <br />Environmental Mana er <br />g Russell George <br />~ Executive Dlfeet0! <br />Trapper Mining Inc <br />. Ronan w. fattany <br />P.O. Box 187 Division Director <br />Craig, CO 81626 Natural Resou¢e Trustee <br />Re: Trapper Mine, C-1981-010; Vegetation sampling proposal for Phase III bond release <br />Deaz Mr. Luke: <br />Thank you for meeting with the Division today and discussing your plans for vegetation sampling for <br />potential Phase II and Phase III bond release application. We had discussed several of the alternative <br />sample adequacy approaches for the Phase III data collection. These three alternative sample adequacy <br />approaches would be implemented if simple random sample collection of 15 to 20 transects does not <br />achieve sample adequacy. The first alternate approach would collect a minimum of 30 transects and apply <br />the reverse null equation to the data. Trapper Mining Inc. proposes using an alpha eaor probability of 0.20 <br />with this approach. The second alternative adequacy approach would collect a minimum of 40 transects <br />and apply the running mean equation. If adequacy is not achieved using these previous approaches, Trapper <br />mining Inc. would cease data collection after 75 samples. <br />These three alternative approaches you detail in the proposed sampling plan are in agreement with the <br />formal rulemaking package that the Division submitted to the OSM in 2003. As of this date, the rule <br />changes have not received final approval. Until the State rule change is finalized, please be awaze that <br />sampling methods need to be in agreement with the approved Rule 4.15.7(2)(c). The running mean <br />equation is intended for stem density data only, and would not be appropriate to apply to cover or <br />production data. <br />Please call me should you have any additional questions. Thank you for the detail with regards to <br />vegetation sampling methodologies. <br />~-~~ <br />Janet H. $ nns ` ~_ <br />Environm ntal Protection Specialist <br />Office o/ Office of Colorado <br />Mined Land Rr~clamation Active and Inactive Mines Geological Survey <br />