Laserfiche WebLink
Table 6 cont. SEDCAD Variables and Basis for Selection <br /> Postmining <br /> Parameter Trapper's Trapper's basis for selection Division's Comment <br /> Selection <br /> Produces the minimum 0.5 inch <br /> Design 2.75 inches of runoff necessary to <br /> Event in 24 hours maintaining program accuracy Same event as used in preming model <br /> (SL22 application Sec 1.4.2). <br /> 61 AMC Trappers selected cover, soil <br /> CN II, 78.8 group, hydrologic conditions Reasonable as per selections of cover, soil <br /> group, hydrologic conditions and C factor. <br /> AMC III and CP factor(see below). <br /> Pasture, Grassland & <br /> Rangeland Postmining land use Reasonable as per postmining land use. <br /> "Good" hydrologic None Reasonable as per"Good" in SCS TR55 for <br /> condition other lands corresponding to <br /> Hydrologic soil group Permit application,Appendix Q <br /> classification "B" Section XII <br /> SEDCAD 4 table for permanent Cover values and treatment practices <br /> CP Factor: 0.014 pasture & rangeland indicate reasonable selection of this <br /> variable <br /> Based on Trapper's SEDCAD 4 modeling using baseline data, the Division finds that the lands <br /> proposed for Phase II bond release are not contributing suspended solids to streamflow or runoff <br /> outside the permit area in excess of premining levels. DRMS approves the SEDCAD evaluation of <br /> sediment production and yield as demonstrated by TMI with Phase H bond release of the SL22 parcels. <br /> Summary and Conclusions <br /> Based upon a review of the mine permit,the applicant's bond release application, the 13 October 2020 <br /> bond release inspection and other prior site inspections, the Division finds that Trapper Mining, Inc. <br /> has replaced topsoil in accordance with the approved reclamation plan. Trapper Mining, Inc. has <br /> established vegetation which supports the approved post-mine land use and meets the approved <br /> success standards. The Division finds that the reclaimed area subject to this bond release is <br /> not contributing suspended solids to streamflow or runoff outside the permit area in excess of pre- <br /> mining levels. <br /> V. PROPOSED DECISION <br /> Based on the above observations, the Division proposes to approve Trapper Mining, Inc.'s request <br /> for a partial Phase II bond release block. This proposed decision will release the applicant from <br /> Phase II reclamation liability for those SL22 bond release parcels totaling 175.0 acres as shown above, <br /> in Table 2. <br /> Permit Number C1981010 <br /> SL22 Page 16 of 18 <br />