2010-05-03_REPORT - C1980007 (9)

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Fall 2009 Subsidence and Geologic Field Observations Box Canyon, Apache Rocks, and South of Divide Mining Areas • 5.24 Photographic Observation Point 11 This particular location has been visited on many occasions and assigned different location numbers each time. For that reason, this location was established as Photographic Observation Point 11 so that continued observations and imagery can be obtained to assess changes that may occur over an extended period of time. This location was not visited and photographed during the fall 2009 field visit. It should be noted that no noticeable changes have been observed in this rockfall area since annual observations were initiated in the summer of 2006. 5.25 Traverse N-N' Traverse N-N' begins at the fork in the Deer Creek and Dry Fork roads and continues southward up the Deer Creek road to a locked gate near two stock water tanks in the upper Deer Creek drainage near the middle of the NW'/ of Section 4, Township 14 South, Range 90 West (see • Maps 2 and 4). This traverse starts above the main mine haulageway along the west side of Longwall Panel E3. It continues southward across Panels E4 and E5 (Map 2). The overburden depth to the E-seam varies from 400 to 500 feet thick. Mostly light reddish gray to light brown soil and alluvium (but some colluvium) derived primarily from clay and silt of the Wasatch Formation was observed along the traverse. The estimated thickness range of the soil, alluvium, and local colluviu:m in the Deer Creek Valley is 50 to 150 feet. This material is expected to yield without cracking during the mining of Longwall Panels E3 through E6. Surface flow in Deer Creek was observed to be approximately 5 gpm near N' (with 1-2 gpm diverted through the stock tanks), about 1-2 gpm near the middle of the traverse, and non- existent at the mouth of the drainage even though there is no current mining in the area. The 831-032.791 Wright Water Engineers, Inc. Page 71 April 2010