Laserfiche WebLink
Subsidence Field Observations <br />West Elk Mine <br />August 28 and 29, 2001 <br />3.2.6 Location 9 <br />Location 9 is above the northern edge of mined-otu longwall panel 13-A. <br />• The overburden thickness to the B-Seam is projected to be nearly ],200 feet. <br />• The crack is located in thin soil and colluvium and trends N35°E and was likely caused <br />by mining in longwall panel 13-A since the 2000 observations. <br />• The crack is straight to irregular, is about 10 feet long, and is as much as 6 inches wide <br />(see video for more detail). <br />3.2.7 Location 10 <br />Location ]0 is about 350 feet north of the larger cracks on Apache Rocks (see Location 7 above) <br />above the eastern edge of mined-out longwall panel l2 near drill hole SOM- I6. <br />• The projected overburden thickness to the B-Seam is 1,350 feet. <br />• The cracks, which are as much as ~'<-inch wide, occur mainly in resistant sandstone <br />outcrops and were observed last year. <br />• The cracks branch and converge, and generally trend N60-70°E and N10°W and <br />N40°W. <br />• Local infilling and some healing and sealing are evident in [he surficial material and <br />soft, weathered bedrock. <br />• The cracks and durable sandstone only show some signs of aging but no infiiling, <br />healing or sealing. <br />• The cracks appear to be about the same width and extent as noted in August 2000. <br />831-032.560 Wright Water Engineers, Inc. Page 11 <br />September 2001 <br />