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effort and expense in constructing reestablished drainages effectively controlling erosion and <br /> downstream sediment deposition. Various sediment control materials and methods and sediment <br /> reducing measures have been implemented on reestablished drainages. Drainages at Trapper Mine are <br /> trapezoidal in shape with a bottom width of 20 feet, grass lined with regularly spaced check dams. <br /> Rock check structures dissipate the energy of flowing water within channels. Debris and sediment <br /> deposition occurs upstream of structures allowing vegetation to establish behind structures, further <br /> stabilizing the channels. This configuration results in shallow flow depths for the design storm and <br /> low flow velocities. Rock Channel slopes are generally 10 percent. Detailed engineering criteria <br /> regarding drainage reconstruction practices can be found in TMI's permit Appendix Q Section <br /> XXXVII. <br /> All lands requested in the current Phase 11 bond release application,SL22,received Phase I bond release <br /> as per Table 2 above. <br /> Phase II Bond Release <br /> Rule 3.03.1(2)(b) states: <br /> "Up to eighty-five percent of the applicable bond amount shall be released upon the establishment <br /> of vegetation supporting the approved post-mining land use and meeting the approved success <br /> standard for cover based on statistically valid data collected during a single year of the liability <br /> period." <br /> And,regarding Phase II bond release,Rule 3.03.1(3)(b) states: <br /> "No more than (60)percent of the bond shall be released so long as the lands to which the release <br /> would be applicable are contributing suspended solids to streamflow or runoff outside the permit <br /> area in excess of premining levels as determined by baseline data or in excess of levels determined <br /> on adjacent nonmined areas." <br /> Regarding Phase H bond release,the approved reclamation plan calls for: <br /> o Specific topsoil replacement depth <br /> o Vegetative cover standard <br /> o Post-mining land use <br /> o Sedimentology estimates. <br /> The approved postmining land use for the land applicable to SL22 is rangeland/wildlife habitat and the <br /> 175 acre bond release block has been reclaimed as such. The revegetation plan is designed to achieve <br /> the approved postmining land use. <br /> After final backfilling and grading, topsoil is required to be placed on the spoil to a depth of 18 <br /> inches on cropland and 12 inches on rangeland. A variation of+/- 2 inches is allowed due to <br /> compaction and operational considerations as per TMI's permit(page 4-256). <br /> There are three different revegetation success criteria for rangeland at the Trapper Mine to which the <br /> reclaimed parcels are compared, as discussed in section III of this document, Observation and Findings: <br /> range sites A, B and C. TMI utilizes a technical standard for demonstrating revegetation success for <br /> Permit Number C1981010 <br /> SL22 Page 7 of 18 <br />