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Subsidence Field Observations <br />West Elk Mine <br />August 28 and 29, 2001 <br />2.0 OVERVIEW OF FIELD SUBSIDENCE STUDIES DURING AUGUST 28-29, <br />2001 <br />1. C. Richard Dunntd, P.E. of Wrigh[ Water Engineers, Inc. (WWE) performed the <br />subsidence field observations and authored this report on behalf of Mountain Coal <br />Company, L.L.C. (MCC). The accompanying video provides additional detail on <br />observations at individual locations. <br />2. MCC provided asix-wheel, all-terrain vehicle (ATV) to maximize efficiency and to <br />allow a better look at the ground during the traverses than would be possible from a <br />closed vehicle. <br />3. Field knowledge of subsidence processes during past studies showed that roads and trails <br />were the most likely sites to see subsidence features (cracks and bulges) and, therefore, <br />were selected as the most efficient method to obtain subsidence information. <br />3.0 OBSERVATIONS ALONG TRAVERSES AND AT INDIVIDUAL LOCATIONS <br />ON AUGUST 28 AND 29 <br />3.1 Subsidence Evaluation on August 28, 2001 <br />The traverses were made in Sylvester Gulch, West Flatiron and Deep Creek (Map 1). <br />3.1.1 Traverse A-A' <br />The locations of Traverse A-A' was along a drill road from drill hole SOM-126 in Sylvester <br />Gulch to the RAV-10 de-gasification drill holes located on a ridge in the southeast West Flatiron <br />area. <br />• The overburden thickness to the B-Seam ranges from 1,050 feet at drill hole SOM-126 to <br />2,250 feet at drill site RAV-10. <br />831-032.560 Wright Water Engineers, Inc. Page 2 <br />September 2001 <br />