2022-01-19_REVISION - C1981022 (19)

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Mine facilities. This process was documented in the reports of inspections conducted on September 19, 2001; February 12,2002;April 3, 2002;May 7, 2002; June 26,2002;July 16, 2002;August 13,2002; December 2, 2002; and June 3,2003. The inspection reports document that cover depth on the pile ranged from 4' to 6' at the time it was spread, and that vegetation was established with no significant loss of material through erosion. The UAV data shows that the final configuration of the pile conforms to the approved post-mining topography,with an outslope of around 21-1:IV. The pile is graded so as to drain to a vaguely defined ditch to the west and south. The pile has been reclaimed for around 20 years, during which time there have been no signs of instability. Summary and Conclusions Based upon a review of the mine permit,the applicant's bond release application, and site inspections, the Division finds that Oxbow Mining,LLC has completed backfilling, grading and drainage reestablishment of the parcels described in Table I in accordance with the approved reclamation plan. PHASE II Most of the sites included in the SL-5 application had already been released from Phase II liability(see Table 1). Vegetative cover at the location of the TC-1 and TC-2 wells was indistinguishable from the surrounding area. Vegetation at the East Yard Refuse Pile was sampled between June 13-15 and 19-26, 2019, and again between June 15-28,2020; in both cases it was part of a larger vegetation sample. Vegetative cover was estimated using the point-intercept method. Cover transects were 25 m long,with sample data points collected at I m intervals, on either side of the transect, spaced 1.5 m apart(giving 50 data points per transect, each reported by individual plant species). Each transect corresponds to a single sample unit. According to the 2019 Vegetation Sampling Report, 15 samples were collected,which satisfied sample adequacy. Total live vegetation cover of 57.73%was reported; a value which includes several noxious weed species:Aegilops cylindrical, Jointed Goatgrass (0.13%);Bromus tectorum, Cheatgrass (5.07%); Cirsium arvense, Canada Thistle (0.13%); Cirsium vulgare,Bull Thistle (0.27%); Convolvulus arvenssis,Field Bindweed(4.27%); and Erodium cicutarium,Redstem Filaree (0.13%). Noxious weed cover was 10%in total,(relative cover of 17.3%). Non-noxious weed cover was 47.73%in total, (relative cover of 82.7%). The data shows that native vegetative cover satisfies the revegetation success criteria(a technical standard of 19.3%total vegetation cover). Summary and Conclusions Based upon a review of the mine permit,the applicant's bond release application, and site inspections, the Division finds that Oxbow Mining,LLC has replaced topsoil in accordance with the approved reclamation plan. Oxbow Mining, LLC has established vegetation which supports the approved post mine land use and meets the approved success standard for vegetative cover. The Division finds that the reclaimed area subject to this bond release is not contributing suspended solids to streamflow or runoff outside the permit area in excess of premining levels or in excess of adjacent nonmined areas. C-1981-022 Page 12 of 16