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23. Trapper did not submit detailed designs for post- mining drainage channels, as required by Rules <br />2.05.3(4), 4.05.3(1), 4.05.3(1)(e), 4.05.3(7). <br />c. Rule 2.05.3(4)(a) — A general plan and detailed design plan shall be submitted for each <br />sediment pond, impoundment, other treatment facility and diversion proposed to be <br />constructed within the permit area. Please provide detailed design plans for each <br />postmining drainage channel. <br />d. Rule 4.05.3(1)(e) — channels must be designed, located, constructed, maintained, and <br />used to minimize adverse impacts to the hydrologic balance, and to be stable. Trapper <br />has offered details on how the channels might be constructed and maintained, but has not <br />provided specific design information. Please provide design information for each <br />postmining drainage channel to include the minimum channel dimensions and details of <br />any required velocity reduction measures. The dimensions and channel properties must <br />be based on the anticipated runoff for each specific watershed, based on watershed size, <br />topography and cover; the design precipitation event; runoff potential, etc. <br />e. Rule 4.05.3(7): <br />i. channel linings, including channel riprap, shall be designed using standard <br />engineering practices to pass safely the design velocities. Please provide design <br />information for each postmining drainage channel to include the minimum <br />channel dimensions and details of required velocity reduction. The dimensions <br />and channel properties must be based on the anticipated runoff for each specific <br />watershed, based on watershed size, topography and cover; the design <br />precipitation event; runoff potential, etc. <br />ii. Freeboard shall be no less than 0.3 feet. Please provide details on the proposed <br />channel dimensions so that the Division can determine whether the designed <br />channels maintain the required freeboard. <br />Trapper must submit the information required in Items (a) through (c) for all postmining drainage <br />channels to be constructed, completed, or reconstructed during the current permit term. <br />Trapper Response to Comment 23: Trapper is still working on a response to this comment. We have <br />encountered problems with a consultant engaged to advise us on this issue and the work is still not complete. <br />24. Trapper did not submit designs for the three proposed sediment ponds that are shown east of the <br />current disturbance boundary, as required by Rules 2.05.3(4) 4.05.5, 4.05.6, and 4.05.9. Prior to <br />any surface disturbance east of the Deal, Middle, East Flume, and East Middle Flume watersheds, <br />Trapper must obtain approval for and construct appropriate sediment control for all areas <br />proposed to be disturbed. Trapper will need to provide the required design information for <br />sediment control measures to be used for proposed disturbance east of Deal, Middle, East Flume, <br />and East Middle Flume watersheds. There is currently a stipulation in place to this effect from <br />Permit Renewal No. 6. Trapper should be aware that prior to any disturbance in the expansion <br />area, including the construction of sediment control facilities, the baseline information required <br />from Rule 2.04; as discusses above, must be submitted and approved by the Division. <br />Trapper Response to Comment 24: Trapper will submit the requested information prior to any mining in <br />the permit expansion area <br />