2011-09-29_PERMIT FILE - M2009056

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Action. Mitigation/Residual Effects: Mitigation and Residual Effects would be similar to the Proposed Alternative 1 Direct and Indirect Impacts: Alternative 1 and associated impacts would be similar to the No Action Alternative. Cumulative Impacts: Alternative 1 and associated cumulative impacts would be similar to the No Action Alternative. Mitigation/Residual Effects: Alternative 1 and associated residual impacts would be similar to the No Action Alternative. Finding on the Public Land Health Standard for Upland Soils: Implementing the Proposed Action will not affect the Land Health Standard for Upland Soils WATER QUALITY, SURFACE AND GROUND (includes a finding on Standard 5) Affected Environment: The proposed mine would be located in the Middle Fork of the South Platte River watershed approximately 400 feet southwest and 80 feet above the river itself. The site is in a dry, upland location with no surface water other then the river nearby. Using data from surrounding wells and the local geology, it appears that the major source of groundwater in the area is located in an alluvial aquifer tributary to the Middle Fork of the South Platte at approximately 50 to 75 feet below ground level. Water yields from this aquifer appear to be quite high with yields of 15 gallons per minute common. Most all of the surrounding wells are for domestic use and greater yields may be possible. Due to the close proximity to the river and the typical transmissivity of alluvial aquifers, groundwater recharge is expected to be fairly quick. Water quality in the river is good and has not been identified by the State of Colorado as not meeting water quality standards on the 303(d) or Monitoring and Evaluation Lists. Information on ground water quality is lacking; however, considering its connectivity to the river and use as a domestic water source nearby, its quality is very likely to be good. There are likely deeper confined aquifers below the shallow alluvial aquifer that could be potential sources of water. Little is known of these aquifers due to the easy access to good water near the surface. Environmental Effects Proposed Action Direct and Indirect Impacts: The Proposed Action would allow a mine covering slightly less than five acres to be located on the public lands. This mine would consist of an open pit on approximately 1.5 acres with equipment and materials covering most of the rest. All water used in the operations would be recycled and not allowed to flow on the ground. To protect surrounding surface water, a berm would be constructed around the site to contain storm water. In addition, this operation is required to comply with the State of Colorado implemented Clean Water Act regulations, which may include the need for a Clean Water Act Phase II Stormwater Permit. This permit requires that a storm water plan be developed and implemented that reduces water pollution to the "maximum extent practicable" in order to protect water quality and aquatic habitat, and ultimately meeting the requirements of the Clean Water Act. 25