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<br />III. COMMENTS -COMPLIANCE <br />Below are comments on the inspection. The comments include discussion of observations <br />made during the inspection. Comments also describe any enforcement actions taken during the <br />inspection and the facts or evidence supporting the enforcement action. <br />This inspection report will summarize observations made by the Division of Minerals and Geology <br />(DMG) regarding the landslides overlying and adjacent to the West Elk Mine's Jumbo Mountain <br />underground coal mine workings. DMG inspectors Dr. Jim Pendleton, David Berry, and <br />Michael Boulay examined these landslides on August 27, 1996, in the company of Norm Every <br />and Phil Schmidt of MCC; a corporate Council for MCC; and Fadra Mautz, daughter of the <br />landowner, Larry Mautz. Larry Mautz joined us after our examination at the Mautz hunting <br />cabin. <br />Previous Analysis -Dames and Moore, 1993 <br />Prior to the DMG inspection, Dr. Pendleton reviewed a 1993 report prepared by Dames and <br />Moore, entitled "Landslide Investigation Report, Jumbo Mountain, Somerset, Colorado for ARCO <br />Coal Company." MCC commissioned this investigation while planning their 'B' seam longwall <br />operation at Jumbo Mountain. This investigation, based on the analysis of extensive boring logs <br />of the Jumbo Mountain Tract, concluded; "Landslide deposits exceeding 100 feet in thickness <br />were penetrated by borings located through a bench or terrace which occupies a zone up to <br />2,000 feet wide between the 6,620-foot and 6,850-foot contours (figure 1). These landslide <br />deposits are underlain by the lower part of the 'B' seam suggesting that a bedding plane or parting <br />in this seam formed the base of major slide movements. The 'B' seam outcrop, therefore, <br />represents the downslope limit of landslide deposits. These deposits clearly represent the remnant <br />of a large ancient landslide." Dames and Moore mapped this landslide as exceeding 500 acres in <br />area, and exceeding 148 feet in thickness. <br />Dames and Moore further observed; "There is no evidence of current instability on the lower, <br />bench portion of the landslide. In fact, the lack of any surface evidence of past movement <br />indicates that this area has been stable for a long period. Scarps up to 12 feet high are present in <br />the upper, steeper south part of the landslide mass as shown on figure 1. These scarps indicate <br />recent movement. The largest of these scarps are evident on both 1974 and 1992 aerial <br />photographs. This indicates that sliding is occurring slowly -probably less than one foot per year <br />of overall downslope movement." The DMG examination of the recent cracking and landslide <br />movement which has occurred does not refute any of Dames and Moore's conclusions. <br />Examination of 1996 Landslide Deposits <br />Approximately 30 to 50 acres of the SWl/4 of Section 24 has been affected by recent landsliding. <br />Mr. Mautz reports that minor cracking was noted by his ranch hands on the roads within the <br />affected area in the fall of 1995, followed by extensive landsliding in May /June of 1996. This is <br />in keeping with Dr. Pendleton's observations of annual spring/summer landsliding in the North <br />Fork Valley over the past 17 years. Cracks and graben-like (steep-sided trapezoidal) extensional <br />troughs up to ten feet wide and five feet deep were examined in several locations towards the <br />