2008-04-25_PERMIT FILE - M2008010

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Letter; Response to adequacy review, Permit Application M-2008-010 4/25/2008 page 6 d. Approximate dates of activity: beginning in Year 1 (2008 or 2009) when reclamation of portions of the site begin, and lasting until Year 22 (2030 or 2031, as planned). e. Imported material will be used for backfill as appropriate based on its characteristics (particle size, density, hardness, homogeneity, and quantity), generally at the toe of highwalls to be backfilled, to fill low spots in the floor of the pit, and other areas where additional material will aid the establishment of the desired slopes and drainage pattern, so that the post-mining land use is better accommodated. Some examples: (1) larger pieces of concrete rubble will be placed on the floor of the pit near the highwalls, stabilized with additional granular materials (from on- or off-site) and then covered with on-site fines and overburden before replacement of topsoil. (2) "Wasted" material excavated from construction projects, such as earth, subsoil, shale, etc. which is relatively small (6" or less) in size will be used as granular materials, then covered with on-site fines and overburden before replacement of topsoil. f. General engineering plan: As with all other backfill, off-site backfill will be placed as engineered fill: Materials greater in dimension than 1 foot will be placed individually, and if slabs, will be placed flat and not on edge. Otherwise materials will be placed in lifts of approximately one foot and compacted to approximately 90% of standard Proctor density before placement of additional materials. Unless materials are of a similar nature to on-site soils and overburden, no backfill shall be placed less than three feet below the planned final (post-reclamation) surface. Larger items (such as large concrete blocks or boulders) shall be placed in suitable potholes in the floor of the pit and have material compacted around them to prevent creation of air cavities. 6. Seed mixes for reclamation of pasture land: It was specifically stated (Exhibit E, Page 27, "Revegetation") that there would "...be no intentional seeding with native species..." in pasture land. We do not view pastureland as significantly different from cropland except in the nature of the use after the crop is grown, as contrasted to rangeland, and believe that this distinction is recognized in the Mineral Rules and Regulations. In both cases, a monocrop or a limited selection of species will be planted and harvested, either by mechanical means or by using the field for pasture for livestock. For example, a dryland alfalfa or annual ryegrass might be planted, or a mix of Paiute Orchardgrass and alfalfa might be used. However, in the interest of establishing firm parameters and of responding to criticisms from the Conservation District president, Attachment 3 provides two seed mixes which will be used if anon-monoculture crop is desired or necessary at some point in the reclamation process.