2025-10-07_GENERAL DOCUMENTS - C1982057

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Permit Number: C1982057 Page 17 of 20 Phase III Conclusion Vegetation Success The following vegetation success standards for 2022 and 2023 parameters were met. o Sample Adequacy: In 2022, sample adequacy for allowable herbaceous cover was met in all areas, while production and woody plant density failed to meet the minimum sample size. In 2023, only the Steep Mountain Brush ERA failed to achieve sample adequacy for allowable herbaceous cover, and all areas failed for production. If sample adequacy was not acquired, the appropriate statistical demonstration for revegetation success was used and the minimum sample size was obtained in accordance with the applicable sections of Rule 4.15.11(2) or (3) as appropriate. o Cover and Production Success: For both years, the mean allowable all-hit herbaceous vegetation cover and production in the BRB6 exceeded the 90% performance standard. This was demonstrated either through direct comparison or a one-sample t-test of the "reverse null" hypothesis, which was passed for all tests. o Woody Plant Density Success: In both 2022 and 2023, the woody plant density in the "Background" area of the BRB6 exceeded the mandatory standard of 180 stems per acre. The non-parametric L-test in 2022 and the one-sample t-test of the "reverse null" hypothesis in 2023were both passed, demonstrating success. o Species Diversity and Composition Success: The BRB6 successfully met the species diversity criteria for both years by passing the mandatory test and at least two of the three alternative tests. o Mandatory Test A (No Overwhelming Dominant): Passed for both years, as the most abundant species had relative cover well below the 60% limit. o Test B (Total Species Density): Passed in 2022 but failed in 2023. o Test C (Species Density Distribution): Passed for both years, with similarity indexes of 81% and 79% respectively, both exceeding the 63% standard. o Test D (Native Species Presence): Passed for both years, as the cumulative number of native species exceeded the weighted average density standard of the reference areas. DRMS concluded that in both 2022 and 2023, sampling results showed the following: o The average allowable all-hit vegetative cover sampled in BRB6 exceeded 90 percent of the area- weighted cover performance standard. o The average allowable herbaceous production sampled in BRB6 also surpassed 90 percent of the production performance standard. o Woody plant density exceeded the mandatory performance standard of 180 stems per acre outlined in the Revegetation Plan. o Sampling demonstrates that for species diversity, BRB6 passed the mandatory test and at least two alternative tests, as outlined in the Revegetation Plan. Based on the SL8 application and associated vegetation report provided by CCAI, the Seneca IIW Mine successfully demonstrated revegetation success for Phase III Bond Release in both 2022 and 2023. This conclusion is supported by a comprehensive evaluation of vegetation cover, production, woody plant density, and species diversity. Based on this finding, the applicant has successfully established diverse vegetation conducive to the post mine land use of livestock grazing and wildlife habitat. According to SPL, livestock grazing has been conducted on the reclaimed lands since 2007 and stocking rates have been developed using ongoing revegetation monitoring data. SPL reports on grazing practices occurring at the site in the annual reclamation reports. Also, wildlife species have been observed by DRMS staff utilizing the reclaimed area.