2022-11-07_REVISION - C1981041 (2)

Home Browse Search

X. Backfilling and Grading Backfill and grading information can be found in Tab 14 Reclamation Plan. Grading of the portal area after sealing the portals began with installation of the French drain shown on Exhibit 6C. The French drain system has three branches. Two of the branches intercept minor seepage from the portal seals. The third branch is designed to intercept water from the hillside southwest of the conveyor entry. This third leg extends above the level of the portal entries to intercept seepage along the existing hillside. This seepage originates from an irrigation pond located above and to the southwest of the portal. The next reclamation step involved grading concrete and cinderblock remaining from demolition of the shop -office complex into the portals and highwall. Sufficient amounts of dirt were mixed with this material to eliminate voids and promote stability of the fill.Dirt for backfll of the portal highwall was from excess material at the unit train loadout. Topsoil was not salvaged from this area,therefore the best available material from the cut areas were used for the final cover. The Unit Train Loadout was converted to industrial use with approval of PR-4. The rail loop and a portion of the rail spur will be left in place since it will be the key feature for the industrial use of the area. See Tab 15, page 15-1 for more detailed information on the post mining land use. Following removal of mine facilities, buildings, and asphalt, and sealing of underground mine openings,all areas affected by surface operations will be backfilled and graded as necessary to stabilize slopes and promote successful revegetation. The anticipated final surface configuration for each affected surface area, as well as existing and proposed post-mine cross-sections, are depicted in Exhibits 6C through 12C, and Exhibits 26, 27 and 28 of the permit application. Original reclamation plans for the South Portals area had entailed retention of existing mine bench and highwall, but the plan had been revised to reflect elimination of the bench and highwall, and to approximate the general nature of the premining topography,prior to the 1993 permit renewal. As a component of the 1995 mid-term review, the Division requested additional detail on final reclamation configuration of the Roadside Refuse Disposal Area (RSRDA), and documentation of reclamation material balances for the entire South Portal area, including the RSRDA. PR-02, approved in 1997, included a more detailed final reclamation plan for the Roadside Refuse Disposal Area (RSRDA) and South Portals disturbance area. Documentation of material balances was also provided in PR-02,in 1997,and relevant post-mine topographic maps and cross-sections were amended. Further refinements of the final reclamation plan for the South Portals and RSRDA, including amended permanent drainage plans,were approved via technical revisions prior to initiation of final reclamation in 2002. RSRDA slopes and terrace drains were reclaimed in 2002, 44