2014-12-12_GENERAL DOCUMENTS - C1981010

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requested in the SL16 Phase II bond release application have been granted approval for Phase I bond release with the approval of the SL -08, SL -11 and SL -14 bond release applications. PHASE II Rule 3.03.1(2)(b) states, "Up to eighty -five percent of the applicable bond amount shall be released upon the establishment of vegetation which supports the approved post- mining land use and which meets the approved success standard for cover, based on statistically valid data collected during a single year of the liability period ". In regard to Phase H bond release, Rule 3.03.2(3)(b) also states, " No more than sixty (60) percent of the bond shall be released so long as the lands to which the release would be applicable are contributing suspended solids to stream flow or runoff outside the permit area in excess of pre - mining levels as determined by baseline data or in excess of levels determined on adjacent non -mined areas ". The approved post -mine land uses at the Trapper Mine are cropland and rangeland/wildlife habitat. The 277.8 -acre bond release block that is the subject of this bond release application (SL -16) has been reclaimed for rangeland/wildlife habitat. The revegetation plan is designed to achieve the approved post - mine land use. After final backfilling and grading, topsoil is placed on the spoil to a depth of 18 inches on cropland and 12 inches on rangeland. A variation of +/- 2 inches is allowed due to compaction and operational considerations. Rangeland /wildlife habitat reclamation parcels are seeded with one of three main seed mixes, depending on the elevation. Range site A &B seed mix corresponds to the highest elevations within the mine site; range site C seed mix the lower elevations. The A and B range sites use the same seed mix which contains various grasses, forbs and shrubs, while the range site C seed mix contains only grasses and forbs. Shrub clumps of approximately 1.6 acres each are established from the transplanting of mature shrubs retrieved from the advancing areas of the pits. TMI utilizes a technical standard for demonstrating revegetation success for vegetative cover on the reclaimed parcels. TMI has identified specific percent effective cover standards for range site A, B and C parcels. The standards were calculated using the Universal Soil Loss Equation and designed such that soil loss due to rill and sheet erosion will not exceed pre -mine levels. The details regarding revegetation success standards at the Trapper mine can be found in section 4.4.1 of Trapper's permit. For range site A, the required herbaceous cover standard is 33% and 19% litter cover for a total 52% effective cover. For range site B, the required herbaceous cover standard is 29% and 23% litter cover for a total effective cover of 52 %. For range site C, the required herbaceous cover standard is 23.6% and 20.0% litter cover for a total effective cover of 43.6 %. These standards for each of the range sites are listed on Table 4.4 -1 of the permit. For this release application, the release block consists of all range A, B and C sites; therefore the revegetation standard for range site A was used to evaluate revegetation success since it has the most conservative standard in accordance with section 4.4.1.5 of Trapper's permit. To demonstrate that runoff from the reclaimed parcels will result in equivalent or lesser sediment contributions as compared to baseline conditions at the mine, TMI submitted two evaluations based on the Universal Soil Loss Equation (LISLE) and a SEDCAD analysis. The USLE provides a basis for predicting the gross erosion per acre from an area on an annual basis. SEDCAD modeling evaluates both runoff and erosion estimates and provides results on the basis of single storm events. Page 6 of 10