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Level 6 is the currently active portion of the mine and requires maintenance and <br />updating of the existing management practices. The access road shows signs of <br />stormwater erosion and the Level 6 pad needs to proactively control stormwater <br />infiltration in order to control any acid rock drainage through the waste rock. <br />Several best management practices are already in place, however in the interest of <br />providing a more comprehensive stormwater plan, additional management <br />practices are proposed and more fully described in the next Section by type. <br />4. Stormwater Management Controls <br />Various stormwater management controls have been in place for a number of <br />years since the implementation of the first CDPS stormwater permit (May 2, <br />1997: Colorado Discharge Permit System - Stormwater Certification No. COR- <br />040199). We intend to upgrade these management practices prior to the 2007 <br />mining season (approximately May to June, 2007) since there are visible signs of <br />stormwater erosion along the Level 6 access road, and the potential for acid rock <br />drainage at the toe of the Level 6 waste rock pile due to stormwater <br />communication with the waste rock materials. A summary of the proposed <br />management practices to address the Level 6 access road concerns as well as the <br />Level 6 waste rock concerns include: <br />Level 6 Access Road <br />Setting: The portion of the Level 6 access road within the mine permitted area <br />and falls within stormwater permit boundaries is approximately 0.25 miles along a <br />steeply sloped hillside. As such, the road provides a stormwater path of travel for <br />overland flows from the above hillside. These flows have sought a low point <br />where erosive materials have been cut through to create a stormwater channel at <br />the bottom of the road, just prior to entering the Level 6 pad. It appears that the <br />combined flows over the distance of the road have created this cut over the past <br />several years. In order to abate this issue the following features will be <br />constructed; <br />• A series of `run-on' channels along the inside track of the road (immediately <br />adjacent to the toe of the hillside) will be cut in order to keep run-on from the <br />above natural slope from entering the road footprint. <br />• The flows within these run-on channels will be routed to three stormwater <br />culverts placed at equal distances along the length of the road. <br />The flows routed through the culverts will be released to the hillside on the <br />downhill side of the road, and carried through riprap baffles comprised of <br />large cobble to boulder-sized materials. These baffles will dissipate flow <br />energy and allow for sediment settling. They will also disperse flows into the <br />natural hillside for easier absorption. <br />• All flows from the access road length will have been circumvented by means <br />of the above combination of features, meaning that the flows will not reach <br />the Level 6 pad itself. <br />Level 6 Waste Rock Pile <br />Page 10 of 37