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2004 Geologic Hazard Field Observations <br />South of Divide Mining Area <br />6. This area contains six local rockfall areas that have locally steep ridges. The area is located <br />neaz the heads of Deer Creek, Poison Creek, Lick Creek, and a tributary of Dry Fork. The six <br />azeas (Map 1), which have an estimated low to moderate rockfal[ potential, aze located above <br />(or partly within the area of mining influence of) longwall panels ES through E8 (portions of <br />Sections 3, 4, 9, and 10, Township 14 South, Range 90 West). <br />7. The area contains 3 separate rockfall areas, with an estimated low to moderate rockfall <br />potential, is located in the Lick Creek area south of any currently planned mining, located in <br />parts of Sections 8, 9, and 16 in Township 14 South, Range 90 West). <br />Of the seven areas listed above, six occur near local drill roads or agricultural access roads that <br />have only local, limited to very limited traffic on them. Any rocks that may fall in these azeas <br />could be readily removed before local traffic is impacted, should rockfalls occur on these remote <br />roads. Evidence of naturally occurring rockfalls, such as remnant boulders at the base of steep <br />slopes, or in the run-out zones of these areas with a rockfall potential, should be documented <br />. prior to mining. <br />It is suggested that signs stating, "Watch for Falling Rock," be posted on the more well-traveled <br />roads, such as the Dry Fork and Main Fork of Minnesota Creek roads, before mining begins. <br />This procedure would be similar to signs posted along such major interstate highways as <br />Interstate 70 in the Glenwood Canyon area in this highly traveled area where the rockfall <br />potential and risk to people is high to very high (compared to the very low to low risk to travelers <br />in the South of Divide area), <br />10.4 Importance of Baseline Landslide and Rockfall Data <br />The most significant landslide in the South of Divide area, in terms of proximity to man-made <br />structures, is located above the northern part of longwall panel E9. It is important to monitor the <br />existing, natural (baseline) conditions before mining begins in order to document their natural <br />state. The cracks, bulges, and depressions observed in the landslide azeas north and south of <br />Minnesota Reservoir are much more extensive and dramatic than those caused by subsidence. <br /> <br />831-032.621 Wright Water Engineers, Inc. Page 45 <br />November 2004 <br />