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Christine Johnston, MCC <br />November 19, 1998 <br />Page 2 <br />of influence. The end result commonly is no residual environmental damage to the <br />overburden or the surface. <br />4. Cracks were observed above longwall Panel 12, where the face has traveled only 1500 <br />feet and above Panel 13, where no extraction mining has been done. Some of these cracks <br />are also larger, deeper, and more extensive than the cracks believed to be mostly related [o <br />subsidence above the northern part of Panel 10, These cracks were much larger and more <br />extensive than desiccation cracks observed in common soil and rock types. It is possible <br />that some type of mass-gravity related spreading of the soil, colluvium, and/or bedrock <br />may have caused the cracking. <br />5. Some of the widest and moss extensive cracks were observed on the north side of Jumbo <br />Mountain in historic landslide areas (as evidenced by hummocky topography, leaning <br />trees, and ponds) above longwall Panels 8 and 9. Cracks were observed in this area that <br />appeared to be only a few weeks to months old. However, longwall mining influence in <br />the crack area would have been complete in March or April 1997. Therefore, these cracks <br />are most likely not mining related at all, but aze only landslide related. <br />Overview of Field Work and Findings on September 9 and 10, 1998 <br />Ron Hanna and I traversed the field area on two of his 4-wheel-drive ATVs. The speed and <br />efficiency of our work was, in my opinion, increased greatly over that of other means of <br />transportation. We traversed the surface above the following existing or planned mine areas in <br />areas that would yield the most important information (based on subsidence knowledge). The <br />areas are shown on Figure 1 and were traversed in following chronological order: <br />September 9 (Locations 1 - 12): <br />1. Panel 10 and the chain pillars between panels 10 and 11 where feasible on September 9. <br />2. Panel 12 (longwall mining in the western 1500 feet of panel) and Panels l2 and 13 <br />(development mining only). <br />September 10 (Locations 13 - 16, CDMG Locations 1-8'): <br />l . Panels 8 and 9 and adjacent aeeas on the northern part of Jumbo Mountain. <br />The following data on surface condition at the various locations is reduced from the videotape of <br />the field investigation on September 9 and l0, 1998. The locations are sequentially numbered <br />' CDMG Locations are from CDMG inspection report dated July 23, 1996. <br />Wright Water Engineers, Inc., 2490 W. 26'" Avenue, Ste. t00A, Denver, CO 80211 <br />Tel. 303/480-1700, Fax. 303!480-1020, email:knvright(idwrightwater.com <br />