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• Introduction <br />This 2000 Subsidence Report is submitted in accordance with Section 2.05.6(c) of <br />Powderhorn Coal Company's Mining and Reclamation Permit. The stipulation requires an <br />annual report of the results of subsidence monitoring inspections. Additional information <br />contained in the report includes a description of the local terrain, vegetation and geology. <br />Powderhorn Coal Company owns and operates two mines in DeBeque Canyon nearthe <br />eastern end of the Grand Valley, in Mesa County, Colorado. The Roadside South Portal Mine <br />was idled in 1996. The Roadside North Portal Mine was idled December 2, 1999. The North <br />Mine was sealed on February 10, 2000. The Roadside South Mine was sealed on April 12, <br />2000. The South Fan was sealed May 22, 2000. The 2 West Portals were sealed on April 24, <br />2000. <br />The investigation of subsidence related effects on the surface of the mine property <br />concentrates on the area mined during the last two years, 1999 through 2000 although no <br />mining occurred in 2000. This area includes only the 2 West Section of the Roadside North <br />Portal Mine. <br />Topography and Vegetation <br />• The topography in the mine area consists of narrow valleys, overly steep canyon walls <br />and small mesas on the northwestern flank of the Grand Mesa. The Colorado River and its <br />flood plain bisect the permit area and provide a corridor for the Union Pacific Railroad. The <br />surface terrain varies from the nearly flat flood plain to nearly vertical cliffs of massive <br />sandstone. The vegetation also varies from Saltbush Desert and Riparian Habitat in the lower <br />elevations toPinyon/Juniper Woodland in the higherelevations. The effectiveness of the visual <br />inspection (or pedestrian survey) of the ground surface for subsidence features is limited by <br />both topography and vegetation. <br />Geology <br />The coal seams mined in the area are contained with the Mr. Garfield formation of the <br />Upper Cretaceous and Tertiary Ages. The river bottom and flood plain contain sand and gravel <br />deposits of Quaternary age. The Cameo seam in its Upper and Lower benches (respectively <br />the Cameo C and Cameo B Seams) are mined in the Roadside North Portal Mine, while only <br />the Cameo B Seam is mined in the Roadside South Portal Mine. <br />• <br />2000 Subsidence Report Page 1 <br />