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West Elk Mine • Importance of Baseline Landslide and Rockfall Data The most significant landslide in the South of Divide mining area, in terms of proximity to man-made structures, is located above the northern part of longwall panel E9 (Exhibit 60B, Map 1). Although there is a large landslide within the area of mining influence of the southeast comer of longwall panel E8 (mostly in the NE'/. of Section 8), the landslides located north and south of Minnesota Reservoir are the most important in the mining area. It is important to monitor the existing, natural (baseline) conditions before mining begins in order to document their natural state. The cracks, bulges, and depressions observed in the landslide areas north and south of Minnesota Reservoir are much more extensive and dramatic than those caused by subsidence. The July 2004 aerial photographs obtained by MCC provides good baseline images of the natural, pre-mining features in the South of Divide mining area. Observations made by Mr. Dunrud in the West Elk mining area indicate that mining may accelerate the natural landslide process, where there are landslides that Gave already become unstable. However, annual observations of the surface cracks and depressions in the landslide area on Jumbo Mountain above mined longwall panels 8 and 9 determined that landslides are very likely only related to natural mass-gravity movements and not related to mining. Baseline information has been gathered in the eight areas with low to moderate rockfall potential that are listed above prior to any mining activities. Evidence of naturally-occurring rockfalls-such as remnant boulders at the base of steep slopes, or in the run-out zones of these areas with a rockfall potentialwill be documented prior to mining. Effects Of Subsidence And Mine-Induced Seismic Activity On Man-Made Structures And Renewable Resources Man-made structures and renewable resources in the South of Divide mining area basically consist of 1) a reservoir (Minnesota Reservoir), 2) stock watering ponds, 3) streams (primarily Dry Fork and the upper part of Lick Creek), 4) roads, and 5) local cabins. Minnesota Reservoir, the ponds, and the Deep Creek Ditch diversion to Dry Fork serve the dual purpose of being both man-made structures and containment structures for the valuable water resources in the area. Based on annual subsidence observations in the Jumbo Mountain, Apache Rocks, and Box Canyon mining areas during the last nine years, the following information is considered appropriate for the South of Divide mining area. Minnesota Reservoir Minnesota Reservoir, which provides storage water primarily for irrigation, is located between two landslides~ne beginning at the north shore and the other beginning at the south shore. As explained above, landslide movement on Jumbo Mountain occurred during unusually wet periods before mining began, during mining, and after mining and subsidence was wmplete. • The conclusions were that landslide movement occurs in response to ground saturation and is not 2.05-l34 Revised November 2004 PRIO