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Potentially acid or toxic-forming spoil material has been and will be identified by sampling regraded spoil, and will be chemically treated or buried with a minimum of four feet of topsoil. By neutralizing and/or isolating any acid or toxic-forming material from the surface, and mixing limited quantities of such material with much greater volumes of alkaline and benign spoil material, any negative effects of problematic material will be ameliorated. The Division approves this method for covering acid and toxic forming materials in order to prevent leaching into surface and ground water and to insure backfill stability. (4.14.3(2)). VIII. Revegetation Information on baseline vegetation for the Seneca II-W Mine permit area can be found in Tab 10. Section 10.1 contains the contents from the previously approved permit application package and Section 10.2 contains the information from the 1997 supplemental baseline study of the Seneca II-W South Extension area. Information on the revegetation plan and revegetation success criteria for the permit area can be found in Tab 22 of the permit application. During the course of the original permit review, a number of concerns azose regazding the control of reference aeeas and reference azea compazabiliry. The applicant proposed, in meetings with the Division, an extended reference area concept, which was subsequently approved. As approved, the applicant will utilize al] undisturbed vegetation cotrununities (representing those to be disturbed by mining) within the permit area as components of "extended reference areas". The components of the extended reference areas will be represented by a minimum of 100 acres of undisturbed aspen community, 300 acres of big sagebtush/grassland community, 450 acres of mixed brush community, and 150 acres of western wheatgrass/alkali sagebrush community. In the II-W South Extension area, the extended reference area will be represented by a minimum of 230 acres of aspen forest, 300 acres of mountain brush, 150 acres of steep mountain brush, 200 acres of sagebrush and 100 acres of wheatgrass/alkali sagebrush. The permanent seedmixes are composed predominantly of native species, and the few introduced species included are desirable and necessary to achieve the approved postmining land use, and are not poisonous or noxious. Two years of monitoring data for various reclaimed aeeas at the Seneca II mine which were seeded with the proposed alfalfa vaziery (Medicago falcata), at the proposed rate (.25 ]bs/acre) indicate that falcata alfalfa does not compete excessively with other seeded species. Given its value as a nitrogen fixer and as wildlife forage, inclusion of the species in the seedmix is warranted. In TR-32, SCC committed to notify the DMG each year with the seed mixes they can obtain from the vendor. If the mix does not match the approved seed mix, SCC will submit a minor revision to the Division for species approval prior to seeding. The Seneca II-W Findings Doctunent 3( November 3, 1999