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Volume 4 of the Trapper Mine permit application includes an assessment of the probable <br /> hydrologic consequences of the proposed mining operation. Each year, Trapper assesses <br /> the ongoing impacts to the hydrologic system in its annual hydrologic report submitted as <br /> Appendix W of the permit application. The probable hydrologic consequences as set forth <br /> 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-0032115 <br /> issued by the Colorado Department of Public Health and Environment. In addition, <br /> the applicant has quarterly reporting requirements as part of its surface water <br /> monitoring program. Acute toxicity testing through bio-monitoring sampling is <br /> required in the following drainages if mine-contaminated water is discharged: <br /> 1. East Flume 2. East Middle Flume 3. East Pyeatt <br /> 4. Horse 5. Middle Flume 6. Oak <br /> B. Diversions and Conveyance of Overland Flow <br /> Drainageway reconstruction is discussed under Section 4.8. 1.3,Vol. IV of the permit <br /> application. Channel lining structures,retention basins, and artificial channel <br /> roughness structures are proposed for use to control erosion. The applicant uses rock <br /> check structures,various geotextiles, and rapid growing vegetation within <br /> 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 increased <br /> sediment loads resulting from disturbance within the ephemeral drainages on the mine <br /> site. All sediment ponds are designed to contain or treat, at a minimum,the 10-year, <br /> 24-hour event and to safely pass the 25-year, 24-hour event. One MSHA size pond <br /> exists on the site in the Coyote drainage. <br /> As per RN6 Portions of haulroads,topsoil stripping areas and mining areas are <br /> projected for the next permit term (2013-2017)outside of the currently approved <br /> drainage and sediment control plan boundaries. Given this,the Division proposed <br /> to approve the renewal application (RN-6)with the following stipulation: <br /> Stipulation No. 21: <br /> The operator must submit and receive approval for a permit or technical revision <br /> to update the drainage and sediment control plan prior to any disturbance outside <br /> of the currently approved drainage and sediment control plan boundary. <br /> As of November 2017 this stipulation has been met as follows: <br /> Trapper submitted pond designs for Deacon and Jeffway ponds. DRMS reviewed <br /> 15 <br />