Laserfiche WebLink
Spring 2013 Subsidence and Geologic Field Observations <br />South of Divide and Dry Fork Mininq Areas (E -Seam) <br />4.7 Traverse F -F <br />This traverse originates along the south side of Dry Fork Road and travels southeastward parallel <br />to the Dry Fork for approximately 4,000 feet across mined and unmined portions of E -seam <br />Longwall Panels E3 and E4 (see Maps 1 and 2) where the overburden depth to the E -seam ranges <br />from slightly less than 700 feet to about 850 feet. Thick soil and colluvium derived primarily from <br />the Wasatch Formation was observed along this traverse. <br />Spring 2012 observations found considerable evidence of subsidence occurring both north and <br />south of the road near the turnoff to the MDW E3 -29 pad as this was above the general vicinity of <br />the E -seam Longwall Panel E3 face at the time. Fall 2012 observations showed continued evidence <br />of subsidence - related cracks but with obvious softening of features from weathering. Spring 2013 <br />observations found that most of these areas have now been regraded and evidence of these <br />subsidence - related features have been obscured and healed. <br />The southern portion of this traverse includes drill road access to four MDW pads above unmined <br />portions of E -seam Longwall Panel E4. These MDW pads include E4 -11, E4 -12. E4 -13 and E4- <br />14. Based on the mapping provided by MCC, longwall mining had not yet occurred beneath these <br />pads. In the case of the MDW E4 -11 pad, longwall mining was nearby but apparently not yet <br />beneath the pad. No cracking was observed on or near the pad at the time of our spring 2013 field <br />visit. Of note was the observation that the entrance road onto the pad was heavily rutted suggesting <br />that saturated subgrade materials underlie the dry road and pad surface (possibly a buried seep or <br />spring). <br />Also of note along this traverse was the observation of several sub - parallel cracks (Location 7) <br />along the road leading to the MDW E4 -12 pad where it crossed over a small drainage. Details <br />associated with these cracks are discussed in Section 4.7.1 below. <br />4.7.1 Location 7 <br />Location 7 is along the access road to MDW E4 -12 where it crosses a small drainage. At this <br />location, several sub - parallel cracks were observed parallel with the road orientation (Figure 11). <br />These cracks were slightly arcuate with upward curvature to the south (upgradient). The largest <br />831 - 032.795 Wright Water Engineers, Inc. Page 20 <br />September 2013 <br />