|
Stormwater Management Plan
<br />Exhibit U — Attachment U -3
<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 />b. Access road improvements and construction (1.8 acres);
<br />c. May Day Idaho Mine Complex road maintenance (includes delineating snow removal
<br />disposal areas benches, and fences, (9.5 acres);
<br />d. Augmentation pond construction with associated piping and diversion structures (8.2
<br />acres);
<br />e. Diversion ditches /rock berms at the Idaho, May Day No. 1 (3.5 acres), No. 2 (3.3 acres),
<br />and May Day No. 3 mine benches (3.2 acres);
<br />f. Run of mine rock stockpiles (May Day No. 1 East and erosion and sedimentation BMPs (
<br />0.5 acres);
<br />g. Existing benches and run of mine rock disposal areas at the Lamb (3.2 acres) and the
<br />Chief portal (0.3acres);
<br />h. Repair the maintenance /core storage structure (former Idaho Mill Building) (acreage
<br />included in the augmentation pond calculated footprint); and
<br />i. Reclaim the disturbed areas with the affected areas (31.4 acres) at the conclusion of
<br />mining activities.
<br />4. Site Soil Information: Existing soils (Exhibit I) data for the drainage area within the permit and
<br />affected areas are provided through the National Resource Conservation Service (NRCS) Custom
<br />Soil Resource Report for the La Plata County Area, Colorado. The soil report identifies:
<br />• Pastorius cobbly loam (8,000 -9,000 feet) and Pescar fine sandy loam (6,500 -8,000 feet)
<br />in areas adjacent to and including the access road;
<br />• Nordicol very stony sandy loam (7,800 - 10,000 feet) for the May Day No 1 area, May
<br />Day No 2;
<br />• Cryothents Rubble for the Lamb portal area; and
<br />• Nordicol very stony sandy loam (8,000- 10,000 feet) and Leadville very stony sandy loam
<br />(7,800- 10,000 feet) for the former Idaho millsite location.
<br />The soils are naturally thin, well drained, well vegetated with the existing rocky slopes, and
<br />because of these characteristics will minimize offsite erosion and sedimentation. Historical
<br />disturbed mine areas were not reclaimed however native volunteer vegetation growth has
<br />stabilized soils within the affected area.
<br />5. Existing vegetation: Vegetation affected by mining is a mixed coniferous and deciduous forest
<br />(Exhibit J) with specific vegetation types generally having the same species present but varying in
<br />dominance. The mixture of vegetation assemblages are influenced by topographic aspect and to a
<br />lesser degree by elevations, and geologic conditions. Topographic slope is a factor only in the La
<br />Plata Floodplain. Primarily, the dominant tree species for the site are aspen and Douglas fir with
<br />ponderosa pine, white fir, blue spruce, and lumber pine also present. The dominant shrub species
<br />are gamble oak and mountain snowberry. Other shrubs found in the community include
<br />chokecherry, wild rose, black elderberry, golden current, Oregon grape, Rocky Mountain maple,
<br />mountain lover, thimbleberry and serviceberry. The herbaceous groundcover includes the
<br />following: bluegrass, puline, western wheat grass, yarrow, common nettle, whipple penstemon,
<br />dandelion, Fremont goosefoot, salsify, bracken, clover, American vetch, medowrue, goldeneye,
<br />Richardson geranium, mariposa -lily, timothy, wild rose, scarlet gilia, gray's fern-leaf lousewort,
<br />rosy paintbrush, porter's lovage, and western wallflower. Disturbed areas exhibit: curlyleaf dock,
<br />common mullein, yellow sweetclover, cheatgrass, and tumble mustard. Currently all areas
<br />Page 7 of 31
<br />
|