PERMFILE137431 - Laserfiche WebLink

Home Browse Search

Rule 2.05 Topography and Drainage All reclamation was carried out in conformance with the initial perrrut application and approved revisions, notably TR-51 (3/31/86 submittal) and TR-52 (9/4/86 submittal) which respectively proposed post reclamation topography and reclaimed area drainage designs for the mine and facilities areas. These revisions included numerous cross sections which compared as-built topography with the approved post mining contour maps. MLRD evaluation of the revisions confirmed that the final reclamation configuration conformed very well with the previously approved post mining design. Similar comparisons using cross sections and final contour surveyed maps were done for the designed and as-built drainage structures. These comparisons also showed past reclamation configurations which varied only slightly from design. Some minor differences were unavoidable due to haul road location, topsoil placement considerations, and minor variations in post mining topography. The as-built topography maps were based on December 3, 1987 over-flight maps. Certified cross sections and as-built topography maps were submitted to MLRD as part of (or addendums co) the September 11, 1987 Phase I bond release application. Field inspections by MLRD staff in October 1987 in response to the partial bond release request verified slope gradients and that the requirements of Rules 4.14.1(2) and 4.09 were met. During re-permitting of the HG mine in 1986, HGCC indicated that the shop/office facilities adjacent to the mine (across CR 53) would remain in place in anticipation of improved market . conditions. Due to continued slow coal market conditions, HGCC submitted a detailed reclamation plan for the shop/office facility area via MR-03 which was approved August 4, 1987 by the MLRD. A past-muting drainage control plan was submitted on September 29, 1986 and approved as TR-52. The plan described and provided supporting documentation for three permanent ditches, sixteen temporary diversions and one permanent impoundment in the mine area. Drainage control was accomplished at all sites in compliance with the approved plan and TR-52. The three permanent ditches were designed and constructed to provide for non-erosive drainage of surface water from the reclaimed mine azea to Pond HG-8. Map 2, Reclamation Sequence and Drainage (see map pocket), shows the existing (post-mining) topography and drainage characteristics of the reclaimed mine site. Two ditches, Ditches 1 and 3, were constructed by modifying roads to serve as permanent drainage channels. The third ditch (Ditch 2) was a natural drainage that was revegetated. These ditches are located in swales on the reclaimed mine area and carry water downslope at controlled rates of flow into a permanent impoundment (Pond HG-8). A diversion ditch on the western edge of the reclaimed area also drains into Pond HG8. The CDMG inspection in October 1987 pursuant to the Phase I bond release application concluded that drainage control had been accomplished at all sites in compliance with the approved plan. Two permanent impoundments (I-IG8 and the shop/office pond) were also incorporated into the final reclamation design through several Technical Revisions which addressed the requirements of Rule 4.05.9. The ponds are compatible with the post-mining land use and will provide a source of water for both livestock and wildlife in the vicinity. Appropriate as-built drawings and . certifications were submitted for the ponds and approved by MLRD, most recently in January 1993. In July of 1992, construction modifications were performed on the three small ponds to achieve compliance with Rule 4.05.6(3)(d) regazding sepazate primary and emergency spillways. Primary design features of the ponds are noted below in Table 2.05-3, Sediment Pond Chazacteristics. T,e-63 1 / Zc 96 9~y/96 2.05-4 ~ ~ Sugm,TTRL