Laserfiche WebLink
Memorandum to Henry Barbe <br />September 27, 2000 <br />Page 3 <br />August 30 (observations made alone) <br />' 1. Traversed above the central to western parts of longwall panels l2 and 13 by ATV. <br />2. Traversed above the position of the longwall face of panel 13A in Horse Gulch on foot. <br />3. Traversed above the eastern to central parts of longwall panels 12 and 13 of Horse Gulch <br />on foot. <br />' Note: No observations were made this year above longwall panels 8 and 9 on Jumbo Mountain, <br />because no new cracks attributed to subsidence were observed during traverses made in 1998 and <br />1999. Also, the cracks observed in 1996 and 1997 on Jumbo were 75 percent to 95 percent <br />attributable to natural mass-gravity movements. <br />' OBSERVATIONS ALONG INDIVIDUAL TRAVERSES AND SITES ON AUGUST 28- <br />30, 2000 <br />August 28-Pre-mining Subsidence Evaluation in Deep Creek-Subsidence <br />Evaluation of Apache Rocks <br />Note: The traverse across the six cross sections in Deep Creek is located in soil and alluvium. <br />' The alluvium consists of clay-, silt-, sand-, pebble-, cobble-, and boulder-size material that varies <br />from a few tens of feet to probably more than 100 feet thick. Projected overburden thickness to <br />' B-Seam on the six cross section traverse lines (from south to north) range from approximately <br />I,O50 to 900 feet. Accuracy of GPS locations for the cross sections and rebar control points, <br />according to Dave Nicewicz, is within a few centimeters of the true location (see Map 1 for <br />locations). <br />Location 1. Located at the southernmost (upstream) cross section in Deep Creek. <br />• A GPS control point is located near the trail. Two rebar control points are installed, one <br />on either side of stream. <br />• An automatic stage data recorder is installed near the west bank of the stream. Bear claw <br />marks were observed on the cover of the recorder. <br />1 • Section is located above the north edge of projected longwall panel 26. <br />Location 2. Located at the 2"a cross section in Deep Creek. <br />• Two rebar control points are installed, one on either side of the stream. <br />• Section is located above the east center of projected longwall panel 25. <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:knvright@wrighlwater.com <br />