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) water from the upper end of the slide area immediately southeast of the borrow site. While no mining activities have occurred, or are planned, for this area, it remains relatively active and susceptible to reactivation particularly during periods of high precipitation. 4.13 Traverse H -H' Traverse H -H' (formerly Traverse N -N') begins where the Deer Creek drainage meets the Dry Fork Road and continues southward up the Deer Creek Road to a locked gate near two stock water tanks (see Map 1 and 2). This traverse is located above the projected E -South Mains and the western ends of mined E -seam Longwall Panels E3 and unmined E -seam Longwall Panels E4 through E6. The lower end of the drainage is located above mined E -seam Longwall Panel E3 which was undermined in December 2012. Spring 2013 observations found no subsidence related features here or elsewhere along this traverse. Specific details associated with this traverse (i.e., topographic description, overburden depth, exposed surficial materials, etc.) are not included in this report but can be found in the Spring 2009 Subsidence Report. 4.14 Traverse I -I' Traverse I -I (formerly Traverse P -P') originates in the Deer Creek drainage adjacent to the lower stock pond (P74) and proceeds eastward (after swinging considerably north and the south) over mined E -seam Longwall Panel E3 and unmined E -seam Longwall Panels E4 and E5 (see Maps 1 and 2). E -seam overburden depths along this traverse vary from a low of 450 feet in the Deer Creek drainage to more than 900 feet over E -seam Longwall Panel E5. The soil and colluvium observed along this traverse are relatively stable and are derived from the Wasatch Formation and from intrusive rocks of the West Elk Mountains overlying consolidated rock units of the Barren Member of the Mesaverde Formation. Numerous posted MDW pads are accessible from this traverse including E3 -6, E3 -12, E3 -17.5, E3 -21, and E3 -25. Each of these sites was visited during the spring 2013 field activities. Our visit to the MDW E3 -6 pad represented the first field visit after longwall mining had occurred beneath the area. Subsidence - related cracking was observed and is described below as Location 8. 831 - 032.795 Wright Water Engineers, Inc. Page 25 September 2013