GENERAL30772 - Laserfiche WebLink

Home Browse Search

is 5372 feet, the 100 year flood is 5373, and the 500 year flood is 5375 feet. All of the proposed entries are above the 50 year, 100 year and 500 year floods, therefore no surface water is likely to enter the mine entries. Also the sealing method proposed for the sloped entries will prevent any significant amounts of water from entering the mine after abandonment. (Estimated flood levels from the U.S. Army Corps of Engineers, Sacramento, California). The B-Seam ventilation shaft opening was found to be well above the flood line of the Scullion Gulch during an inspection by Mr. Dan Mathews, DMG Reclamation Specialist. Vertical shafts will be filled for the entire depth of the shaft with incombustible rubble from the demolition of surface facilities. The top of the hole will then be filled with a plug of concrete at least 6 inches thick. The concrete plug will have a 2-inch diameter vent pipe extending 15 feet above the surface of the shaft. See Figure V-1. All vertical shaft openings will be above any possible flood levels and will not be located near any surface runoff watercourses. This plan applies to the B-Seam ventilation shaft. A plan for post-mining ventilation system will be submitted to the appropriate regulatory authority before the shutdown of any major mine ventilation system. The post-mining system will be required to prevent the buildup of methane or other explosive gases within the abandoned mine. The post-mining ventilation system will be approved and installed ready for operation before the shutdown of the ventilation system that it is intended to replace. All openings required for monitoring or for ventilation purposes which are located in areas without controlled access will be covered by a grate and screen set in a frame of steel or concrete. The grate shall be locked or secured at all times to prevent unauthorized entry. The details of the frame, grate, and screen are subject to the approval of the appropriate regulatory authorities. These openings will be inspected at periodic intervals to verify the condition of the opening and the grating. The openings will be fenced and signs posted identifying the hazardous nature of the openings. Openings which are built before actual mine operation or are allowed to remain after mine operations cease will have frames and gratings installed as indicated above. V.B BackfillingandContouring Except for the upgraded county road and coal waste banks in the disposal area, all surface areas that are disturbed incidental to the mining activities will be backfilled, graded to approximate original contours, and revegetated. Disturbed areas that will not be redisturbed during the mine operation or final regrading were backfilled, regraded and revegetated as part of the original constructionwork. Concrete portal face walls will be removed along with the corrugated steel entry tunnels not ExhibitE-Reclamation Plan Rio Blanco Special Use Permit#81.1 September2000 5