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1 <br />' Memorandum to Christine Johnston <br />October 7, 1999 <br />Page 4 <br />1 depression (Figure 3). It likely was caused by a combination of erosion and <br />hydrocompaction. There is no side drainage; the water appazently came northward down <br />the road. <br />' Location 3. Located in bottom of Box Canyon about 150 ft south of southern three gate roads of <br />longwall Panel 18. <br />• Projected overburden thickness to B-Seam is 850 ft. <br />• No features that could be mistaken for subsidence were observed, except the depression <br />mentioned under Location 2. <br /> <br />CJ <br /> <br /> <br /> <br />1 <br />• The brush is very thick; we cannot see the lower canyon sidewalk. <br />Tweety Gulch, as identified by MCC, is the unnamed drainage between Box Canyon and <br />Sylvester Gulch. Pictures of Tweety Gulch were taken from the old highway on the north side of <br />the North Fork. More could be seen from this vantagepoint of the surface above longwall Panel <br />18 than in the thick brush on site. <br />• Overburden thickness, relative to B-Seam, <br />ranges from 600 to 1,000 ft. <br />• The burned, cracked, and steaming area can <br />be seen above the Oliver No. 2 portal area <br />(Figure 4). Small landslide features can be <br />seen west of the old portal area. The mine <br />was operated in the late 1940s and early <br />19sos. <br />t • Small debris flows have occurred in the <br />Barren Member of the Mesaverde <br />Formation on the east side o.f Tweety Gulch <br />above the western part of longwall Panel <br />18. <br />1 Reexamination of Sites Visited in September 1998 above Northeastern Part of <br />Panel 10 <br />Reexamination of Locations 1, 2, and 3 of September 1998: <br />• No cracks were observed at these sites, where subsidence cracks were present last yeaz. <br />' Wright Water Engineers, Inc., 2490 W. 26'" Avznue, Ste. 100A, Deriver, CO 80211 <br />Tel. 303/480.1700; Fax. 303/480.7020, e-mail:krwright@wrightwater.com <br />