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Grand Island Resources,LLC Page 5 <br /> Idaho Tunnel Portal—Slope Stability Analysis <br /> 1.2.3. Tunnel Geology <br /> Figure 1 depicts a 1954 geologic map'.of the initial portions of the Idaho Tunnel which was annotated by <br /> the previous operator and local miner, Tom Hendricks. As depicted on this map the ground conditions <br /> starting at the portal consist of"Alluvial Rock" transitioning to "Decomposed Granite" and then "Weak <br /> Hard Rock", none of which are proper terms to describe the geology, although they do provide some <br /> indications in that regard. <br /> Geology exposed in the initial portal excavation and collapse void includes fractured and weathered <br /> blocky gneiss in the left wall or 'rib' when looking into the tunnel (Photograph 3). This material is <br /> interpreted as similar to the "Weak Hard Rock"depicted on Figure 1. <br /> .. <br /> } <br /> •.. t <br /> y <br /> p41 <br /> k' q r, r <br /> '44 <br /> M t <br /> Photograph 3—Weathered and fractured gneiss in the left rib beneath the portal collapse. Green paint <br /> marks at 4-ft intervals mark the approximate location for the next steel sets. <br /> The right rib of the portal in the area of the collapse occurs in granular decomposed gneiss overlying <br /> deeply weathered blocky gneiss (Photograph 4). This material is interpreted as similar to the <br /> "Decomposed Granite"depicted on Figure 1. <br /> Regolith and colluvial soils are exposed in the collapse void above the tunnel horizon (Photograph 5), <br /> excavation wing walls (Photograph 6), and the Caribou Road cut. This material is interpreted as similar <br /> to the "Alluvial Rock"depicted on Figure 1. <br /> 1 Moore, F.B., Cavender, W.S., and Kaiser, E.P., 1954; "Geology and Uranium Deposits of the Caribou Area, Boulder County, <br /> Colorado."US Geological Survey Trace Elements Investigations Report 228,March 1954 <br />