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is 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 /> Drainage way reconstruction is discussed under Section 4.8.1.3, Vol. IV of the <br /> permit application. Channel lining structures, retention basins, and artificial <br /> channel roughness structures are proposed for use to control erosion. The applicant <br /> uses rock 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 <br /> increased sediment loads resulting from disturbance within the ephemeral drainages <br /> on the mine site. All sediment ponds are designed to contain or treat, at a <br /> minimum, the 10-year, 24-hour event and to safely pass the 25-year, 24-hour event. <br /> One MSHA size pond exists on the site in the Coyote drainage. <br /> D. Surface and Ground Water Monitoring <br /> 1. The applicant will conduct monitoring of ground water in a manner approved by <br /> the Division. The ground water monitoring plan can be found in Section 4.8. <br /> 5.2a, Vol. IV of the permit application (4.05.13(1)). <br /> 2. The applicant will conduct monitoring of surface water in a manner approved <br /> by the Division. The monitoring plan was submitted under 2.05.6(3)(b)(iv) and <br /> can be found in Section 4.8.5.1a of the permit application, Vol. IV(4.05.13(2)). <br /> The Division reviewed the surface and ground water monitoring plans as part of the <br /> permit revision PR9 review process. These monitoring plans are adequate to <br /> monitor for the development of impacts, if any should develop. Well GP09 <br /> functions as the designated the groundwater point of compliance for the Third White <br /> Sandstone aquifer, and the Coy as the point of compliance for the Flume Gulch <br /> alluvium. <br /> Trapper received an updated NPDES permit in June of 2020 from the Colorado <br /> Department of Public Health and Environment(CDPHE). Discharge to Deer Gulch <br /> was removed and discharge was added to the outfalls of the new Deacon and <br /> Jeffway ponds. No new or revised water monitoring is being proposed under PR9 <br /> other than monitoring as per Water Quality Control Division Requirements. <br /> E. Probable Hydrologic Consequences <br /> The model for leachate formation and migration at the Trapper Mine is based on a <br /> study conducted by the U.S. Geological Survey at the Seneca 11 Mine in Routt <br /> 17 <br />