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Stormwater Management Plan <br />Exhibit U — Attachment U -3 <br />Site Description <br />1. Nature of Construction (Mining) Activities At The Site: <br />a. If required, an augmentation pond will be constructed <br />Wildcat Mining Corporation <br />May Day Idaho Mine Complex — 112d Permit Application <br />Revised August, 2011 <br />Exhibit U — Rule 6.4.21 <br />The May Day Idaho Mine Complex is located in Section 21 and 28, T28N, R11 W, Lat 37.352765; Long <br />108.074094, La Plata County, Colorado. The access road into the May Day Idaho Mine Complex <br />originates off County Road 124, near the community of Mayday, Colorado approximately 16 miles <br />northwest of Durango, Colorado. The mine site is primarily located on Little Deadwood Gulch a tributary <br />to the La Plata River which ultimately drains into the Animas River. <br />Access site road foundation consist of unconsolidated river gravels on the west side of the La Plata River <br />and bedrock limestone and consolidated sandstone on the east side. Construction activities will be <br />focused on establishing road access from the west side of the La Plata River across river alluvium to the <br />east side of the River. Pre - existing roads built in or around 1930 will be used to the maximum extent <br />possible to support mining activities. Pre - existing roads will be upgraded and maintained to comply with <br />stormwater management control requirements, to allow access for emergency vehicles, and mine <br />equipment while implementing road safety features. Upgrading features will include temporary BMPs, <br />constructing debris basins, ditches, swales, snow storage areas, berms, culverts, and check dams. <br />b. Wildcat intends to mill historic stockpiled ore. The stockpiled ore is located underground <br />in the stope, inside the May Day No. 1 portal. In order to access stockpiled ore in the <br />May Day No. 1 underground workings, material collapsed in the portal must be removed. <br />Minimal disturbance is anticipated as part of this construction activity because it will <br />occur primarily underground. The activities will include: <br />• implementing the stormwater management BMP for the mine site; <br />and <br />• stabilizing the May Day No. 1 Portal. <br />c. Additional ore will be mined within May Day No. 1 (3,000 -5,000 tons) when the existing <br />stockpiled ore presently stored within the stope, and on the surface (May Day No. 2 <br />(1,000 + tons), Lamb portal bench (1,000 -2,000 tons), and the former Idaho Mill site <br />(1,000 -2,000 tons), has been processed (Stockpiled ore locations are illustrated on Figure <br />D -5). <br />d. Wildcat will finalize construction of the new access road, protecting the wetlands <br />adjacent to the La Plata River and installing a culvert, check dams, drainage blankets, <br />gabions, inside road ditches', drainage swales, silt fencing and placement of straw <br />bales /wattles [CASQA (California Stormwater Quality Association, 2003)] in appropriate <br />locations. The total disturbance for this activity will be approximately 1.8 acres <br />(approximately 0.7 acres was disturbed during road construction in 2008 and 0.9 acres <br />was disturbed in 2009). BMPs described above will be implemented as outlined in the <br />1 Road ditches are designed to convey the 10 year - 24 hour storm from a standard drainage area equal to or less than <br />20 acres. <br />Page 5 of 31 <br />