Laserfiche WebLink
Appendix K-5 <br />• Results of BE&K/Terranext investigations and studies to date indicate that the Keenesburg <br />Mine site can continue to be operated and closed in a matmer consistent with current <br />environmental standards and regulations, namely, the CDMG and the CDPHE developed and <br />adopted regulations which meet or exceed the requirements of the Subtitle D Regulations <br />outlined in the Resource Conservation and Recovery Act (RCRA) as published in the October <br />9, 1991 Federal Register. The CDPHE "Regulations Pertaining to Solid Waste Disposal Sites <br />and Facilities," 6 CCR 1007-2, adopted on January 30, 1994, are currently used by <br />BE&K/Terranext for all its landfill design projects within Colorado. In accordance with this <br />document, a landfill owner/operator must provide a permanent surface water runoff control <br />system to effectively limit the site post-closure 100-year total peak discharge to that which <br />would occur under "historical" conditions (i.e., in this case, the pre-mining site condition). <br />The estimated "historical" 100-year total peak discharge is 355 cfs and the associated runoff <br />volume is 69 acre-feet (uncontrolled) for the CEC site (total contributing drainage area of 1.70 <br />square miles without the Dugout Pond). For the Sediment Pond 2 site (permitted to be <br />reclaimed) with contributing drainage area of 1.34 square miles, the estimated 100-year peak <br />discharge is 280 cfs and the associated runoff volume is 54 acre-feet. Also, since the Dugout <br />Pond will remain as a permanent impoundment at site closure, it will effectively provide for <br />better than 100-year flood runoff control for the contributing drainage area above it (0.36 <br />square mile) as noted previously. Therefore, for CEC site post-closure conditions, the total <br />100-year peak discharge and associated runoff volume conveyed off the property to Ennis <br />Draw would be less than that for `historical" conditions. <br />If you should have any questions concerning the post-closure surface water runoff control issue <br />discussed herein, please call me at (303) 914-1775. <br />• <br />4 <br />BEAK/TerraNeXt <br />