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activity in eighty to ninety years, and if entry is still possible, it is very dangerous. There <br />may be no oxygen and the roof may collapse. Yet there are a few sites where sub-surface <br />controls, including grouting or sealing areas above the mine from the surface may be <br />possible, and they aze being investigated. <br />Passive treatment must be tailored to a site and to the specific metals needing <br />removal. Some treatment techniques can be ruled out for all but a handful of sites. Only <br />a few sites have relatively large flat areas needed for treatment using settling ponds or <br />wetlands, and these types of treatment lose their effectiveness when temperatures drop <br />well below freezing during much of the year. Techniques such as anoxic drains need less <br />space, but they need more maintenance to prevent them from clogging and are better <br />suited for dischazges with low iron and aluminum coirtent. Metals such as zinc and <br />manganese are more difficult to remove because pH must be raised to a high level to <br />make them precipitate. The pH must reach about 11 to get manganese to drop out. Each <br />site needs to be thoroughly characterized and evaluated to determine the feasibility of <br />metal and acid removal. <br />Remediation Ranl~ing and Prioritization <br />The Colorado Division of Mineral and Geology, with direction from ARSG, has <br />taken a first cut at estimating the feasibility of reclamation for 140 sites (some of which <br />have multiple features) in the Upper Animas Basin. Their four reports -one for Mineral <br />Creek, Cement Creek, Upper Animas above Eureka, and Upper Animas below Eureka. <br />(Appendices 10A, B, C, and D of the UAA) -describe sites, diagram sites, list results of <br />water quality and leachate data (from mine waste piles), and recommend remediatioa <br />techniques. The reports are quite extensive yet most sites will require more specific <br />process and design engineering before construction begins. <br />In conjunction with and addition to these reports, the ARSG Prioritization <br />committee characterized and ranked 159 mine waste sites (waste rock piles and mill <br />tailings} and 174 draining adits relative to one another. While ranking of sites was based <br />upon anal~,~tical data determined through sampling, testing and monitoring, the sites were <br />prioritized by combining ranking information with more subjective attributes. Various <br />weights were placed on different attributes of a site depending on which attribute was <br />thought to be relatively more important than another. This enabled the group to focus <br />remediation towards achievement of specific goals based upon available technology, <br />funding, and property owner cooperation. Spreadsheets containing this information were <br />the basis for developing the remediation scenarios and calculating potential reductions. <br />V4'hile ranking was completed during 2002, prioritization was intended to be a dynamic <br />process to be revisited prior to each working season. <br />Mine Waste Pfles <br />Mine waste piles were characterized relative to their potential impact on the <br />environment. Certain attributes of each site are listed on the rank and prioritization <br />spreadsheets (UAA Appendix lOFj. Pote~ial for contribution of metals and acidity to <br />nearby streams was determined by leachate tests. Ten to twenty samples were taken from <br />12 <br />