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Grand Island Resources, LLC Page 5 <br />Idaho Tunnel Portal – Slope Stability Analysis <br />Applied GeoLogic LLC 5/7/2020 <br />1.2.3. Tunnel Geology <br />Figure 1 depicts a 1954 geologic map1 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 />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