Laserfiche WebLink
Spring 2017 Subsidence and Geologic Field Observations <br />South of Divide and Dry Fork Mining Areas <br />with several subsidence cracks were observed on the road leading to MVB E6-14 pad (Location <br />4). Lastly, several subsidence cracks were observed leading onto, and on, the MVB E6-14 pad <br />(Location 5). <br />There are two locations associated with this traverse from which photographs from east- and west - <br />facing overview locations have historically been obtained. Photographs were again obtained from <br />these vantage points and photographic comparisons to previous images found no substantive <br />differences. <br />4.3.1 Location 2 <br />Location 2 is depicted on Map 1 as on MVB E6-13 but actually includes both the pad and an area <br />of approximately 130 linear feet along the access road beginning at its departure from the main <br />drill road. The access road features are located above the northern edge of the longwall panel near <br />the tailgate entries. The pad features are located approximately 150 feet south of the tailgate <br />entries. <br />On the MVB pad, three sub -parallel subsidence cracks (approximate bearing of N10°E) were <br />observed cutting across both the entrance road to the pad and the pad itself. The longest of these <br />cracks runs intermittently for approximately 250 feet from the mud pit on the north to the cut slope <br />on the south and has maximum dimensions of 8 inches wide and 14 inches deep (Figure 3). The <br />two sub -parallel cracks were also intermittent but with smaller width and depth dimensions. Of <br />note was the observation that the maximum depth dimensions on each of the cracks was near the <br />southern end of the MVB pad, suggesting a likely brittle sandstone layer a few feet beneath this <br />area (Figure 4). <br />Several subsidence cracks were observed along the access road immediately after its departure <br />from the main road. The orientation of these cracks was approximately N45°E. Several parallel <br />cracks were observed along this 130 -foot length with the longest totaling about 20 feet. The <br />maximum dimension of these longer cracks was 1 inch wide and 4 inches deep. One of the smaller <br />cracks (i.e., 3 feet in length) was observed to have a width of 8 inches and depth of 3 feet. Images <br />from this location were unsatisfactory in representation of the observed features and therefore not <br />831-032.799 Wright Water Engineers, Inc. Page 13 <br />August 2017 <br />