2009-05-12_REVISION - C1981025 (8)

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D. An alternative subdrainage system for the coal mine waste area was proposed and approved. The Division found that the alternative would ensure the applicable static safety factor, stability of the fill, and protection of the surface and ground water [Rule 4.10.3(5)]. A naturally occurring subdrainage system at the coal mine waste area is described in a report by Chen & Associates, which is presented in Appendix 4-C of the permit application package. The design of the refuse pile provides a long-term static safety factor of 1.8 and a seismic safety factor of 1.5. These factors are based on geotechnical testing and engineering analysis as detailed in the Chen report. E. The applicant submitted certifications, and the Division field-verified, that there is four feet of cover on the coal processing waste bank [Rule 4.10.4(5)]. V. Revegetation Revegetation information is found in Section 4.4.2.3-Revegetation Plan of the permit, inclusive of pages 4-54 through 4-65. All disturbed areas of the Permit, other than the permanent Developed Water Resources area and the area of four reclaimed water monitoring flumes, have been reclaimed and Phase III Bond Release approved. The Division approved the inclusion of several introduced species in the seed mix. These species include: Russian wildrye (Elymus 'unceus), Crested wheatgrass (Agropyron cristatum), Cicer milkvetch (Astra ag lus cicer), and Orchardgrass Pact lis lomerata . None are considered poisonous or noxious. Four different seed mixes were approved. Seed Mix No. 1 was developed for use on south-facing slopes and harsh locations, like the dry, exposed Mancos Shale areas. Seed Mix No. 2 utilized species adapted for more mesic, cooler, and flatter sites. Seed Mix No. 3 contained species for use on the reclaimed refuse disposal area, mine area, and less harsh road cuts. The fourth seed mix provided a quick effective cover for topsoil stockpiles. The mine was reclaimed between 1986 and 1987 with final grading, seed preparation, and seeding practices performed in the fall of 1987. Seed was planted using a drill seeder in accessible areas with straw mulch crimped for stability. In locations where steep slopes prohibited drill seeding, the appropriate seed mix was broadcast and straw mulch applied and netted for stability. Woods rose Rosa woodsii), mountain mahogany (Cercocarpos montanus), and serviceberry (Amelanchier alnifolia) were added to the seed mixes prior to planting. The operator committed to live transplant additional shrubs if necessary, to achieve the required woody plant densities. In 1992, Technical Revision No. 12 was submitted to modify the reclamation success standards for the majority of the loadout area due to an approved post-mining land use change to residential/recreational. Reclamation success for the small remaining area at the loadout was measured by comparing it to an extended reference area. The revegetation success criteria for the reclaimed lands are: species diversity, vegetative cover, herbaceous production, and woody plant density. Success was determined by comparison with an undisturbed extended reference area. Baseline data was not collected on the mine area prior to disturbance. The mine area was disturbed prior to the enactment of the current law. In the North Thompson Creek C-1981-025 Permit Renewal 05 12 May 2009 31