2021-03-15_REVISION - C1981044 (2)

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revegetation success standards outlined in the PAP, also DRMS received a letter from the USDA on 10 February 2021 concurring the vegetation established in this area would support the approved post mine land use in accordance with Exhibit 24 of the PAP. Vegetation Production The 2014 mean allowable herbaceous production in the Strip Pit was 610.1 lbs/acre, exceeding the 90% performance standard of 298.0 lbs/acre. Sample adequacy was not achieved therefore a null hypothesis test was conducted in accordance with Rule 4.15.11(2)(c),the critical t value of 1.311 is exceeded the T calc value of 4.428,therefore the null hypothesis is rejected and the revegetation is deemed successful. For 2015 the mean allowable production of the Strip Pit was found to be 606.7 lbs/acre,exceeding the 90% performance standard of 298.7 lbs/acre. Sample adequacy was achieved however the number of samples was not greater than 30,therefore a null hypothesis test was conducted in accordance with Rule 4.15.11(2)(c),the critical t value of 1.311 is exceeded the T calc value of 6.801,therefore the null hypothesis is rejected and the revegetation is deemed successful. Woody Plant Density Thirty transects were located and sampled for woody plant density. Sample adequacy was not achieved in the reclaimed area or the reference area,therefore a non-parametric rank order L test was used to demonstrate success in both years in accordance with Rule 4.15.11(3)(a). In 2014, 1548.3 stems per acre were observed,exceeding the 900 stems per acre standard. L tests yielded a result of 788.9 for the 80% confidence limit which is greater than 70%of the success standard(700 stems)and is therefore deemed successful. The 1356.8 stems per acre observed in 2015 exceeds the performance standard. The L tests for 2015 yielded 915.409 for the 80%confidence which is greater than 70%of the success standard(700 stems) and is therefore deemed successful. Species Diversity In 2014 six species contributed more than 5.0%to the H value and the four largest contributing species totaled 50.3%toward H,meeting the success criteria. Also,mandatory A test was passed. Agropyron cristatum, at 32.5%was the most abundant species,alternative B and C tests were passed as per the SL4 application. In 2015 nine species contributed more than 5.0%to the H value and the four largest contributed species a combined total of 58.3%toward H,meeting the success criteria. Mandatory A test was passed with no single specie contributing greater that 40%relative cover. Alternative B test was passed with the mean species density in the Reference area at 11.5 species per 100 sq.m. and 12.8 in the Strip Pit. The reclaimed area was greater than the reference area, demonstrating success. Alternative C test was also passed with a mean species density in the reference area of 82% exceeding the 90%standard of 63%demonstrating success. Final reclamation success was evaluated for vegetative cover, herbaceous productivity, species Permit Number C1981044 Page 24 of 25