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I wanted to double-check with your office on the mine's discharge permit <br />CO-0029599 that was terminated in 2005 (see attached WQCD termination letter dated 4/20/06). <br />I am trying to verify that termination of the discharge permit accounted for the perpetual <br />discharge of iron-laden water from these mines. This mine water currently passes through a <br />three-pond passive treatment system before discharging into North Thompson Creek (at former <br />outfall 001). DRMS termination of jurisdiction over the site would result in no further <br />maintenance requirement for the ponds or the pvc pipe that routes the mine water to the <br />ponds. The discharge has been a fairly constant 20 to 100 gpm since <br />1995 when the mine portals were closed. On one occasion the discharge rose to 150 - 200 gpm <br />for several months. <br />Several years of monthly sampling between 1986 and 1995 show the discharge is always <br />alkaline, with potentially dissolvable iron content usually less than 1 mg/1, but <br />occasionally rising to around 7 mg/1. The most recent sample was from April 2007 when the <br />discharge was estimated to be 10 gpm and a lab sample found total iron of 6.8 mg/l (North <br />Thompson Creek at the time was flowing several cfs, with no iron detected in it using a field <br />test kit). <br />So that I may complete my review, would you please let me know if the termination of the <br />discharge permit in 2005 accounted for the perpetual mine water discharge at the North <br />Thompson Creek Mines. If my review eventually results in DRMS issuing a proposed decision to <br />approve the final bond release and terminate jurisdiction, then your office will receive a <br />letter notifying you of the proposed decision, and giving you the opportunity to submit <br />comments. <br />If you have any questions or need additional information, please do not hesitate to call me. <br />I thank you in advance for your assistance, <br />Tom Kaldenbach <br />Environmental Protection Specialist <br />Division of Reclamation, Mining and Safety <br />1313 Sherman St., Rm. 215 <br />Denver, CO 80203 <br />Phone (303) 866-4923 <br />Email tom.kaldenbach@state.co.us <br />4