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Introduction <br />This report about subsidence in the area of the mine workings is submitted in <br />• response to Stipulation 12 of Powderhom Coal Company's Mining and Reclamation Permit. <br />The stipulation requires an annual report on the results of subsidence monitoring <br />inspections. Contained in the report are details of the local terrain, vegetation and geology; <br />as well as, descriptions of the result of the surface subsidence inspections and the <br />underground mining practices. <br />The operations of Powderhom Coal Company are conducted at the eastern edge of the <br />Grand Valley in Mesa County, Colorado. Two underground mines have been operated. <br />Roadside South Portal has been idle since 1996. The mine is being ventilated and water is <br />being pumped to allow future access. Roadside North Portal was active during 1998 and <br />produced a total of 471,251 tons of raw coal. <br />Investigation of subsidence related effects on the surface of the mine property <br />concentrated on the areas mined during the last three years, 1996 through 1998. This <br />includes the entire north west section of Roadside North and that area mined with the FCT <br />during 1996 in Roadside South Mine. <br />• Topography and Vegetation <br />The topography in the mine area consists of steeply incised valleys on the <br />northwestern flank of the Grand Mesa. The Colorado River bisects the permit area. The <br />surface terrain varies from the nearly flat areas of the river floodplain to nearly vertical cliffs <br />of massive sandstone. The vegetation also varies from Saltbush desert and Riparian <br />habitat in the lower reaches to Pinyon Juniper Woodland in the higher elevations. <br />The effectiveness of the visual inspection of the ground surface for subsidence <br />features is influenced by both the topography and the vegetation. The vegetation can be <br />so sparse that the ground surface can be inspected with relative ease or so thick that it is <br />impossible to view the area more than a few feet around the person doing the inspection. <br />The topography in the area can be so steep that any cracking or depressions could be <br />interpreted as a part of the natural landfonn or the topograhpy may obscure features. <br /> <br />1998 Subsidence Page 1 12-31-98 <br />