Laserfiche WebLink
Fall 2014 Subsidence and Geologic Field Observations <br />South of Divide and Dry Fork Mining Areas <br />as well as unmined portions of E -seam Longwall Panel E6. The western end of this traverse is <br />adjacent to Minnesota Reservoir and outside the proposed E -seam mining influences of Longwall <br />Panels E1 through E9. <br />Photographic Observation Point 1 is located along this traverse approximately 300 feet southwest <br />of point G of Traverse G -G'. Photographs were taken at this location to compare images taken <br />during previous field visits. No noted changes were observed. <br />Several side roads lead a short distance away from the Dry Fork Road to MDW pads. These roads <br />and pads were previously described as separate traverses. Starting with the Spring 2013 Report, <br />only the longest of these side roads to MDW pads are individually discussed as a separate traverse <br />(see Traverse D -D', E -E', F -F', and J -J'). The smaller traverses (sub - traverses) are included in this <br />discussion for Traverse C -C. <br />The three sub - traverses between Traverse G -G' (Horse Gulch) and Traverse F -F' revealed no new <br />subsidence - related features during our fall 2014 field visit. One of these sub - traverses to MDW <br />pads E2 -19, E2 -23, and E2 -26.5 (including the road and pads) has now been fully reclaimed. <br />No new subsidence - related features were observed for MDW pads (E3 -32.5, E -36, E3 -40, E344, <br />E347, E4 -9, and E4 -10) located adjacent to the Dry Fork Road between Traverse F -F' and <br />Traverse A -A'. Subsidence features had been previously observed during times of active mining <br />along each of these sub - traverses or at the MDW pads, but subsequent observations have found <br />these features to have healed substantially within the first year and were not visible during the fall <br />2014 field visit. <br />Another small sub - traverse, approximately 250 feet east of Traverse A -A', leads to the MDW E4- <br />7 and E4 -8 pads. While no subsidence - related features have been noted on MDW E4 -7, subsidence <br />cracks have been observed on the MDW E4 -8 pad. The first observance of subsidence cracks was <br />during the spring 2013 field visit when the MDW E4 -8 pad was above the active longwall mining <br />face. Figure 1 shows the pad several months later during our fall 2013 field visit. Note the sub - <br />parallel subsidence cracks of this portion of the MDW pad, each with a general north -south <br />orientation (roughly parallel with the outside edge of the pad). While subsidence was a significant <br />factor in the creation of these cracks, the extensive fill on this portion of the pad was also subject <br />831 - 032.796 Wright Water Engineers, Inc. Page 7 <br />March 2015 <br />