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<br />still mean the water quality will be classified as good for <br />irrigation and aquatic life. No receiving stream standards, <br />water quality criteria, or irrigation standards should be <br />exceeded. Also, past monitoring has not identified any <br />unsuitable levels of dissolved solids in Thompson Creek. The <br />magnitude of this salt increase will decrease at the confluence <br />of Thompson Creek and the Crystal River. The low flow of record <br />on the Crystal River near .Redstone is 22 cfs (28 years of <br />data), which would result in a dilution ratio of 22cfs/4.7cfs <br />or about 5:1 ratio. <br />The sediment ponds and refuse area at the mine may add an <br />additional salt load to the Thompson Creek drainage. However, <br />the impacts are expected to be small due to their limited <br />discharge, and the fact that the discharge would be during a <br />rain event, when dilution factors are highest. <br />The mine may affect the surface water regime in still another <br />way. Mining may cause the depletion of springs and seeps above <br />the undermined areas. A spring and seep survey conducted by <br />the mine has only identified two springs within the five-year <br />mine plan area. Both springs (designated on the mine <br />subsidence map) flow less than one gallon per minute, except <br />during the spring, when site SP-2 flows 20-40 gallons per <br />minute. Both springs flow from the Upper Sandstone and are not <br />adjudicated. Based on the low flow and poor quality, it does <br />not appear that the springs were, or are, a significant <br />component of the surface water regime. Any depletions will <br />therefore not be a significant impact to the hydrologic balance. <br />The mine loadout facility should not significantly impact the <br />Roaring Fork River. The loadout disturbed less than 20 acres. <br />Sediment control structures have been removed following <br />reclamation of the site and no quantifiable impacts were <br />documented at the loadout. <br />III. Sealing of Drilled Holes and Underground Openings <br />A. The applicant has proposed to manage development, exploration, <br />drill or bore holes, wells, or other exposed underground openings <br />in a manner other than by sealing and plugging. The Division <br />proposes to approve the manner proposed since it should prevent <br />acid or toxic drainage, minimize disturbance to the prevailing <br />hydrologic balance, and ensure the safety of people, livestock, <br />fish and wildlife, and machinery in the permit and adjacent areas <br />(4.07.1). <br />Specifically, the airshaft at the No. 1 Mine portal needs to be <br />left open, because the plug that was previously installed burst due <br />to excessive hydrostatic pressures caused by mine flooding. <br />However, a permanent enclosure needs to be built around the <br />airshaft to protect people, livestock, and wildlife. In addition, <br />the status of three piezometers, P2-l, P2-2, and P2-3, located <br />inside the No. 3 Mine, is unknown. The piezometers are thought to <br />-:9- <br />