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Reclamation Feasibility Report - Virginia Canyon <br />Based upon normalized flows, the total heavy metals loading at the mouth of Virginia Canyon from <br />surface drainage was approximately 40 pounds per day. The majority of the load is comprised of <br />manganese and zinc. Manganese and zinc comprise more than half of the heavy metals in the <br />snowmelt drainage. Although there is considerable iron in the upper half of the watershed, most <br />appears to precipitate before reaching the confluence with Clear Creek. <br />Storm Flow <br />Water quality samples were collected during a summer thunderstorm on August 7, 2000. The <br />thunderstorm was estimated to produce approximately 1 inch of precipitation. The thunderstorm <br />initially was of high intensity, followed by two hours of steady rain. Runoff from this storm was more <br />than i normal because of light rain showers two days prior to the sampled thunderstorm and a similar <br />thunderstorm the previous day. The lowest sampling site (station VC-24) could not be sampled <br />safely because of large rock carried by the flowing water. Measured total loading during this <br />thunderstorm was 4 orders of magnitude higher than measured during spring snowmelt. The <br />loading rate measured at sampling site VC-22 was about 195,000 pound of total metals per day, or <br />about 8,100 pounds of total metals per hour. Most of this metals load was carried in the sediments. <br />The dissolved metals loading measured at sampling site VC-22 was approximately 2,350 pound per <br />day or about 100 pounds per hour. <br />This thunderstorm was between a 2-year (0.89") and 5-year (1.21") 2-hour duration storm event. <br />This thunderstorm caused minor mudflows onto the Virginia Canyon roads and resulted in no <br />flooding near the confluence with Clear Creek. In recent years there have been several <br />thunderstorms that have resulted in flooding of the housing area near the confluence. <br />The largest increase in total metals loading (approximately 44,000 lbs./day) came from Boomerang <br />Gulch. This is followed by a total metal loading of approximately 36,000 lbs./day from the Two <br />Brothers/Bald Eagle area and approximately 21,000 lbs./day from Seaton Gulch. Of the <br />approximately 36,000 lbs./day from the Two Brothers/ Bald Eagle area, a total metals loading of <br />about 21,000 lbs./day was measured from mine waste sampling sites 13 and 14. <br />In contrast, the largest dissolved metals loading occurred in the Two Brothers/Bald Eagle Mine area <br />(approximately 5,000 lbs./day). Most of the dissolved load from this area (over 3,500 lbs./day) <br />evidently precipitated or was adsorbed to the sediments by the time the flow reached Robinson <br />Gulch. The second and third largest dissolved loading was from Boomerang Gulch and the <br />headwaters above the Crown Point and Virginia. <br />There was minor total and dissolved loading from Robinson Gulch, Buttermilk Gulch and Seaton <br />Gulch below the Seaton Mine. Most of the storm loading from Seaton Gulch evidently occurs below <br />sampling site #20. <br />In general, the highest dissolved metals concentrations were measured at sampling site VC-6 below <br />the Two Brothers/Bald Eagle Mine. High dissolved metals concentrations were also found in direct <br />runoff from mine waste piles at sampling sites VC-14 and VC-25. <br />Mine Drainage <br />There have been 4 mines that historically have drained in Virginia Canyon. The draining mines were <br />sampled on May 9, 2000 and August 8, 2000. The Clarissa Mine (sampling site DM-1) did not drain <br />16 <br />