Laserfiche WebLink
be the same as those given in the permit. All reestablished drainages are delineated on Map 1 of the <br /> bond release application, entitled; SL24 Phase II Bond Release Area Delineation. TMI has put in <br /> significant efforts in constructing drainages, effectively controlling erosion and downstream sediment <br /> deposition. Various sediment control materials and methods and sediment reducing measures have <br /> been implemented on reestablished drainages. Drainages at Trapper Mine are trapezoidal in shape with <br /> a bottom width of approximately 20 feet, grass lined with regularly spaced check dams. Rock check <br /> structures dissipate the energy of flowing water within channels. Debris and sediment deposition <br /> occurs upstream of structures allowing vegetation to establish behind structures, further stabilizing the <br /> channels. This configuration results in shallow flow depths for the design storm and low now <br /> velocities. Rock Channel slopes are generally 10 percent. Detailed engineering criteria regarding <br /> drainage reconstruction practices can be found in TMI's permit Appendix Q Section XXXVII. <br /> All lands requested in the current Phase II bond release application, SL24,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 <br /> establishment of vegetation supporting the approved post-mining land use and meeting the <br /> approved success standard for cover based on statistically valid data collected during a single <br /> year of the liability 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 <br /> release would be applicable are contributing suspended solids to streamflow or runoff outside <br /> the permit area in excess of premining levels as determined by baseline data or in excess of <br /> levels determined on adjacent nonmined areas." <br /> Regarding Phase II 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 SL24 is rangeland/wildlife habitat and <br /> the 298.3 acre bond release block has been reclaimed as such. The revegetation plan is designed to <br /> achieve 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 inches <br /> on cropland and 12 inches on rangeland. A variation of+/-2 inches is allowed due to compaction and <br /> operational considerations as per TMI's permit(page 4-256). <br /> Trapper Mine Inc. maintains three different revegetation success criteria for rangeland to which the <br /> reclaimed parcels are compared, as discussed in section III of this document, Observation and <br /> Permit Number C1981010 <br /> SL24 Page 6 of 16 <br />