Laserfiche WebLink
• Introduction <br />Subsidence monitoring consists primarily of visual surface inspections in the spring and <br />fall. The inspections include areas over the next years' mining projections and over the past <br />two years of actual mining. In the case of Coal and Jerry Creeks, subsidence monuments are <br />surveyed immediately prior to undermining and twice a year for two years subsequent to <br />undermining. Mining ceased at the Roadside Portals on December 2, 1999. There are no <br />mining projections and subsidence monitoring has been performed for two years subsequent <br />to mining. Therefore, this is the final annual subsidence report required by the permit until <br />mining resumes at the Roadside North or South Portals. <br />This 2001 Subsidence Report is submitted in accordance with Section 2.05.6(c) of <br />Powderhorn Coal Company's Mining and Reclamation Permit. An annual report of the results <br />of subsidence monitoring inspections is required. Additional information contained in the report <br />includes a description of the local terrain, vegetation and geology. <br />Powderhorn Coal Company owns two mines in DeBeque Canyon near the eastern end <br />of the Grand Valley, in Mesa County, Colorado. The Roadside South Portal Mine was idled in <br />• 1996. The Roadside North Portal Mine was idled December 2, 1999. The North Mine was <br />sealed on February 10, 2000. The Roadside South Mine was sealed on April 12, 2000. The <br />South Fan was sealed May 22, 2000. The 2 West Portals were sealed on April 24, 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 2001 although no <br />mining occurred in 2000 or 2001. This area includes only the 2 West Section of the Roadside <br />North 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 to Pinyon/Juniper Woodland in the higherelevations. The effectiveness of the visual <br />2001 Subsidence Report Page 1 <br />