Laserfiche WebLink
Memorandum to Henry Barbe <br />September 27, 2000 <br />Page 6 <br />• Crack area is about 320 feet (by pace distance) in a north-south direction and about 150 <br />feet in an east-west direction. <br />' • Located 350 feet (by pace distance) north of the northern edge of this area of cracks is <br />another area of cracks about 50 feet wide in a north-south direction and about 75 feet <br />long in an east-west direction. The cracks trend (I) N60-70°E and are as much as'/< inch <br />wide, and (2) NIO°W and N40°W and aze as much as %z inch wide. <br />' • The calculated angle of draw is 11° to 12°, based on the location of the crack area relative <br />to longwall panels 12 and 13. The maximum calculated tensile strain in the sandstone <br />outcrop at Apache Rocks ranges from 0.23 percent to 0.47 percent (0.0023 ft/ft to 0.0047 <br />ft/ft). This calculation is based on a maximum total extension of 0.75 to 1.5 feet across <br />the crack area totaling 320 feet. <br /> <br /> <br />1 <br /> <br />L~ <br /> <br />1 <br /> <br /> <br />Figure 2 <br />Eastward view oja tension crack located at Apache Rocks The crack, as much as 3 inches wide, <br />trends N65-75 °W. The crack is not visib/e in the foreground, where the soil and co/luvium is more <br />than about 1.5 feet thick. <br /> <br />Wright Water Engineers, Inc., 2490 W. 26'" Avenue, Ste. 100A, Denver, CO 80211 <br />Tel. 303/480-1700; Fax. 303/480-1020, e-mail:krwright@wrighlwater.com <br /> <br />