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• III. Hydrologic Balance - Rule 4.05 <br />Volume 4 of the Trapper Mine permit application includes an assessment of the <br />probable hydrologic consequences of the proposed mining operation. Each year <br />Trapper assesses the ongoing impacts to the hydrologic system in its annual hydrologic <br />report submitted as Appendix W of the permit application. The probable hydrologic <br />consequences as set forth in Volume 4 and Appendix W are summarized below. <br />A. Water Quality Standards and Effluent Limitations <br />Surface discharge at the Trapper Mine is monitored under CDPS permit # CO- <br />0032115 issued by the Colorado Department of Public Health and Environment. <br />In addition, the applicant has quarterly reporting requirements imposed by the <br />Division as part of its surface water monitoring program. Acute toxicity testing <br />through bio-monitoring sampling is required in No Name, East Buzzard, Coyote, <br />West Buzzard, Middle Pyeatt, and East Pyeatt drainages due to pit dewatering. No <br />specific approvals are required by the Division under this section. <br />B. Stream Channel Diversions <br />Drainage way reconstruction is discussed under Section 4.8.1.3, Vol. IV of the <br />permit application. <br />• 1. Channel lining structures, retention basins, and artificial channel roughness <br />structures are proposed for use to control erosion. These means are proposed <br />to be approved by the Division being that they are necessary to control <br />erosion; they are stable and will require infrequent maintenance. The <br />applicant uses rock check structures, various geotextiles, and rapid growing <br />vegetation within reconstructed drainages to control erosion. (4.05.4(2)(a)). <br />C. Sedimentation Ponds <br />Sediment ponds are discussed under Section 4.8.1.4, Vol. IV of the permit <br />application. <br />The applicant uses sedimentation ponds in all disturbed drainages to control the <br />increased sediment loads within the ephemeral drainages on the mine site. All <br />sediment ponds are designed to contain or treat the 10-year, 24-hour event and <br />safely pass the 25-year, 24-hour event, at a minimum. One MSHA size pond <br />exists on the site in the Coyote drainage. <br />Technical Revision TR-103 approved the resizing of Horse Gulch Pond to address <br />the activities proposed in PR-06. TR-103 was approved on July 29, 2008. <br />D. Surface and Ground Water Monitoring <br />• <br />Trapper Mine 24 September 21, 2009