Laserfiche WebLink
COLORADO <br />Division of Reclamation, <br />Mining and Safety <br />Department of Natural Resources <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />Memorandum <br />TO: Jason Musick, DRMS <br />FROM: Jared Ebert, DRMS <br />DATE: November 16, 2016 <br />RE: Bowie No. 1 Mine, C-1981-038, Technical Revision No. 62 (TR62), Vegetation Success <br />Review <br />Per your request, I have reviewed the "Phase II Bond Release Revegetation Evaluation Report, 2016" <br />submitted with TR62. This report serves as a cover standard justification that untreated drainage from the <br />reclaimed East Mine is not contributing solids to stream flow or run-off outside of the permit area in <br />excess of pre -mining levels. This justification is part of a pond removal demonstration for Ponds 1 <br />through 4 and the gob pile pond according to the cover letter for TR62. <br />The reclamation success standards for the East Mine area (formally known as Orchard Valley Mine) are <br />discussed in section 2.05.4 of the permit and specifically listed in Volume 9A, Vegetation Appendix, Part <br />2, Page 6). The revegetation report submitted with the TR62 application evaluates the vegetation cover <br />for the East Mine area to determine if it meets the revegetation success standard for vegetation cover <br />approved in the permit. The approved permit states that the ground cover is required to exceed 40%. <br />Cedar Creek Associates, Inc. (Cedar Creek) was contracted in 2016 by the permittee to evaluate the East <br />Mine for Phase II bond release. Vegetation sampling was conducted on June 30, 2016 by Cedar Creek. <br />The approved permit does not specify what sampling methodology will be used to evaluate reclaimed <br />areas for revegetation success. However, the methods used by Cedar Creek identified in the TR62 <br />revegetation evaluation report are in accordance with the vegetation cover sampling methodology <br />outlined in Rule 4.15.11 (1) and (1)(a). Thirty sample transects were evaluated and Cedar Creek <br />demonstrated that a statistically adequate number of samples were taken in accordance with Rule <br />4.15.11(2)(a). <br />With regard for meeting the revegetation success standard for cover, according to the evaluation, the East <br />Mine's perennial cover was found to be 50.27% with an additional 5.03% contributed from annual and <br />biennial cover (equates to the maximum of 10% relative cover allowed by the Division's bond release <br />guidelines) equates to a total allowable plant cover of 55.34%. This number exceeds the revegetation <br />success standard of 40%, and since statistical adequacy was demonstrated, by direct comparison, the <br />vegetation cover for the East Mine can be deemed successful. <br />Using Microsoft Excel, I replicated Table 3 of the revegetation evaluation report in order to verify the <br />results presented in the report. The excel file is attached. Based on this verification, I concur that the <br />total perennial cover at the mine was measured to be 50.27%. However, I could not replicate how Cedar <br />Creek found that 5.03% cover; attributed by annual and biennial species, can also contribute to meeting <br />1313 Sherman Street, Room 215, Denver, CO 80203 P 303.866.3567 F 303.832.8106 http://mining.state.co.us I h <br />John W. Hickentooper, Governor I Mike King, Executive Director I Virginia Brannon, Director r 1g76 <br />