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Page 17 of 27 <br /> been reclaimed. <br /> B. Stream Channel Diversions <br /> Exhibit 2 of the permit application discusses drainage way construction, channel lining structures, <br /> retention basins,and artificial channel roughness structures for erosion control. These features are found <br /> to be in compliance (4.05.4(2)(a)). <br /> C. Sediment control <br /> Information on the sediment control system is presented in Section 4.05 and in Exhibit 18 of the permit <br /> application. Permit Map 26 shows the location of the components of the sediment control system.All <br /> surface disturbance run-off at the Williams Fork Mines, other than from those areas discussed above, is <br /> routed to sediment ponds by a series of diversion ditches designed to treat the water for suspended solids. <br /> D. Surface and Ground Water Monitoring <br /> The permittee monitors ground water and surface water as approved by the Division. Monitoring plans <br /> are set forth in Exhibit 29 of the permit application. The Division reviewed the ground and surface water <br /> monitoring plans and found them adequate for identifying any impacts that develop. The Division has <br /> approved the monitoring plans for ground water(4.05.13(1)(a))and surface water(4.05.13(2)(a)). These <br /> plans are followed when the operator is actively mining. The operator may follow a reduced monitoring <br /> plan (Exhibit 29,Appendix D)that the Division approved for implementation while the mine is in <br /> temporary cessation. <br /> E. Probable Hydrologic Consequences <br /> Projected Impacts <br /> Section 2.05 of the permit application includes an assessment of the probable hydrologic consequences of <br /> the mining operation. Those consequences are summarized as: <br /> 1. Maximum inflow of ground water into the mines' during mining was estimated at <br /> 2,490 gpm. <br /> 2. Continued drawdown in the Middle Sandstone was expected to be the most significant <br /> impact caused by Mines 5 and 6. <br /> 3. About one-half square mile of the Twentymile Sandstone was expected to be <br /> undermined by longwall mining in the E and F seams. Impacts to the Twentymile <br /> Sandstone were deemed very unlikely. No significant dewatering of the Twentymile <br /> was anticipated. Twentymile water quality was not expected to be impacted. It was <br /> considered unlikely that any open fractures would extend from the longwall areas up to <br /> Williams Fork Mines Prepared by: R ReiRey M.S. GISP <br /> C1981044 December 2023 <br />