2013-09-27_REPORT - C1980007 (4)

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Spring 2013 Subsidence and Geologic Field Observations South of Divide and Dry Fork Mining Areas (E -Seam) The three smaller sub - traverses between Horse Gulch and Traverse F -F' revealed no new subsidence - related features during our spring 2013 field visit. This was also true for the MDW pads (E3 -32.5, E -36 and E3 -40) located adjacent to the Dry Fork Road. Subsidence features had been noted along each of these traverses or at the MDW pads previously, but subsequent observations found these features to have healed substantially within the first year and were not visible during the spring 2013 field visit. Of note was the first small sub - traverse east of Horse Gulch and north of the Dry Fork Road which passes a frequently photographed stock pond (USFS Water Resources Pond P -62). The water level in this pond appeared to be low during our spring 2013 field visit. Photo comparisons with images from previously years finds the level during 2013 to be similar to that observed during our spring 2012 field visit. These low water conditions are consistent with the very low snowfall and rain totals during the last two years. Another of the small sub - traverses along Traverse C -C originates on the north side of the Dry Fork Road approximately 600 feet west of point A'. This small traverse leads to MDW pads E3 -47 and E3 -44. Mining occurred beneath this area in March 2012. During our spring 2012 field visit, we observed weathered subsidence cracks on the west and south sides of the MDW E3 -47 pad in a nearly north/south orientation. No cracks were noted on this pad during our spring 2013 field visit. Subsidence cracks were also observed along this small traverse on the south, west and northwest sides of the MDW E3 -44 pad during the spring 2012 field visit. Spring 2013 field observations found continued evidence of subsidence cracks along the outside edge of the pad where the greatest amount of fill had been placed. Three semi - parallel cracks mimic the outside edge of the pad and appear to have been exacerbated by the differential settlement of pad fill material (Figure 1). These non - continuous cracks covered a linear distance of about 120 feet with a maximum width of 0.75 inches and a maximum depth of 4 inches. Both of these pads are located above the middle third of E -seam Longwall Panel E3 with an overburden thickness of about 1,100 feet. Another small sub - traverse is located on the south side of Dry Fork Road approximately 1,300 feet west of point A'. This sub - traverse leads to MDW pads for E4 -9 and E4 -10. The E -seam longwall mining face of Panel E4 had recently passed beneath the MDW E4 -9 pad and was passing beneath the MDW E4 -10 pad at the time of our spring 2013 field visit. As a result, subsidence cracks were 831 - 032.795 Wright Water Engineers, Inc. Page 10 September 2013