Laserfiche WebLink
Ouray Silver Mines Inc. <br /> Technical Revision 11 March 26, 2020 <br /> truncates sampling days resulting in more trips to and from the mine and therefore <br /> unnecessary safety risks. Total phosphorus and all other parameters on the list(except for <br /> pH)have hold times that do not require daily shipping. <br /> 2.2 Pilot Passive Treatment Materials Placement <br /> OSMI requests approval to place treatment media that was used during a pilot test of the passive <br /> mine water treatment system within the disturbance boundary to be used either in the full-scale <br /> treatment system or as soil amendments during reclamation. <br /> As a part of designing and permitting a new passive treatment system for the Revenue Tunnel <br /> discharge in response to an enforcement action with the Colorado Department of Public Health <br /> and Environment(CDPHE) and in accordance with TR-10, a pilot passive treatment system was <br /> constructed underground in the Mine's Coarse Ore Bin area. This system was successfully <br /> piloted and permitted in 2018 and 2019. Now that the pilot testing is complete, the treatment <br /> media and other equipment used in the pilot test need to be removed from underground to make <br /> way for ore handling. OSMI proposes to temporarily stockpile the treatment media on the <br /> surface within the permitted disturbance area for use at a later date. The ultimate disposition of <br /> this materials will either be as an organic rich media to be used at certain locations within the <br /> monitored site boundary to facilitate plant growth, or may be placed directly into the newly <br /> constructed, full-size sulfate reducing bioreactor as treatment media to reduce the amount of <br /> materials hauled on site. The areas considered for depositing this material are shown on Map F- <br /> la. <br /> The pilot test, a summary of which is provided in Appendix 1, consisted of two parallel trains (A <br /> and B). The treatment media used at each stage of these parallel trains is described below. All <br /> materials were commercially sourced. <br /> • Transitional Aerobic Wetland: two 55-gallon barrels containing 7 cubic feet each of <br /> sand and gravel <br /> • Sulfate Reducing Bioreactor(SRB): two 2,500-gallon tanks contain 5%manure, 30% <br /> wood chips, 15%hay/straw, 20%limestone, and 30%gravel <br /> • Anaerobic Wetland: two 275-gallon containers (approximately 36 cubic feet each)of <br /> 30%wood chips, 50%sand, 5%manure, 15%hay/straw and 30%gravel. <br /> • Aerobic Wetlands: four 55-gallon barrels (7 cubic feet each)of 75%sand and 25% <br /> gravel <br /> Following completion of the pilot test, mine water was routed back into the ditch and the <br /> treatment media was allowed to dry. OSMI collected composite samples from each stage of the <br /> system for Synthetic Precipitation Leachate Procedure(SPLP)tests to evaluate potential runoff <br /> quality. Results from the composite tests are provided in Appendix 1. The material's leachate <br /> met groundwater and stormwater standards except for the SRB composite as described below. <br /> Note, the only leachable metals present in the treatment media are metals removed from the <br /> treated water during the pilot test resulting in no net gain in metals loading from any leaching of <br /> these materials <br /> Page 5 of 8 <br />