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July 8,2011 The Union Milling Company PO Box 36099 Denver, Colorado 80236 Attention: Mike Elder John Danio Subject: Slope Stability Evaluation Tailings Pond Embankment and Future Tailings Slope Union Mill Leadville, Colorado Project No. DN45,584 -130 CTL I THOMPSON 0 a g e 0 0 0 0 \ 0© o This letter presents the results of our slope stability evaluation for the proposed tailing pond embankment at the Union Mill and the future tailings slope. Union Mill is located north of Highway 24 and southwest of Leadville, in Lake County, Colorado. The legal description for the property is: portions of Sections 28 and 33, Township 9 South, Range 80 West. The access drive is about % mile south west of County Road 23 (Airport Road) on the north side of Highway 24. There is an existing mill facility and tailings pond at the site. The general mill location is shown on Figure 1. We understand the existing tailings and embankment will be removed and then a compacted fill embankment will be constructed. The facility will include two separate ponds as shown on Figure 2. The embankment will have a 2.5:1 (horizontal to vertical) outside face, and a 2:1 interior face. A clay liner with specified permeability of 1x 10 gal /day /ft will be installed on the interior face and floor. Seepage /leak collection wells will be installed on top of the clay. The pond will then be lined with a man -made material and the existing tailings replaced. The pond will then be put into service for future milling operations. Once the pond is filled to the crest of the new embankment, four additional, 5 -foot lifts of tailing materials will be added. The lifts will be placed using cyclone methods typical for tailings facilities. The scope of our work included: ■ Drilling two exploratory borings on or near the existing embankment; • Testing the classification and strength of the material anticipated for the embankment, the underlying native soils, the existing on -site fill stockpile, and a sample of tailings material provided to us; • Evaluating the slope stability of the embankment and the final tailings configuration; and 1971 West 12th Avenue 1 Denver, Colorado 802041 Telephone: 303- 825 -0777 Fax: 303- 825 -4252