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2004 Geologic Hazard Field Observations <br />South of Divide Mining Area <br />• have been observed in alluvium above mined longwall panels in the Apache Rocks and Box <br />Canyon mining areas. <br />It is important to continue ongoing surface-water monitoring in the Dry Fork and Lick Creek <br />drainages in order to compaze historic information derived from annual subsidence observations <br />in the West Elk Mine azea with field measurements in selected areas in the South of Divide <br />mining azea. Subsidence depressions, slope changes, and strain are expected to occur in above <br />longwall panels E2 through E8 in Dry Fork and its tributaries and in the north fork of Lick Creek <br />when the underlying panels are mined. <br />The greatest depression, slope change, and strain aze projected to occur above the solid coal <br />bamers and mined longwall panel boundaries, such as above the west ends of longwall panels E2 <br />and E3 in 350 to 400 feet of overburden (Table 1). Depressions, ranging in depth from 8.4 to <br />11.2 feet, are projected. Local slope changes (tIlt), ranging from 1.3 to 6.4 percent, aze projected <br />to occur should 14 feet of coal be extracted in this azea. The range of maximum tensile and <br />• compressive horizontal strain is projected to be 0.7 to 4.2 percent. Subsidence depressions and <br />changes in gradient will be less above the gate road pillars, because the gate road pillars are <br />projected to yield during mining by as much as 4 feet (Table 1). <br />• <br />No subsidence depressions or changes in stream gradient were observed in Deep Creek, located <br />about 1,050 feet above mined longwall panel 17 during the annual traverse in July 2004. There <br />was no observable change in stream gradient or in stream flow. The depressions and change in <br />stream gradient were appazently sufficiently gradual, so as to not be perceived during the traverse <br />along the trail by the stream. <br />9.4 Springs, Water-Bearing Zones, and Ground Water Wells <br />The Mountain Coal Company Spring and Stock Pond Location Map for the South of Divide <br />shows one decreed spring (Spring 21), three springs found flowing at every site visit (in 1975, <br />1977, 1979, and 1980), thirty-three intemlittent springs, and two groundwater wells that aze <br />currently monitored. Only a few springs in the West Elk Mine azea indicate a source from a local <br />831-032.621 Wright Water Engineers, Inc. Page 35 <br />November 2004 <br />