Laserfiche WebLink
Trapper Mining, Inc. <br />G 1981 -010; PR7 <br />Adequacy Review No. 2 <br />Page 9 of 15 <br />Map M -5 l «ill continue to represent all culverts oui the site as a refereuice regardless of tli6r <br />status «ithin active miuing, disturbed or undisturbed areas of the site. <br />Future culverts are currentl' sllio«ui o�i map M -5l as a refere�ice. Table 4.82 does riot contain <br />their designs vet as the hydrologic models acid designs have riot bee�i completed for their <br />respective watersheds, Wheui this Nvorlc is completed Trapper «Till submw't the required <br />infonnatio�i as �iecessar . <br />Table 4.82A was also updated acid is e�iclosed due to aui incoms'ste�icY bet «ee�i the table acid <br />map M -5 l . <br />b. Division's Response: The Division concurs with Trapper's response, this item is considered <br />resolved. <br />23. Trapper did not submit detailed designs for post - mining drainage channels, as required by Rules <br />2.05.3(4), 4.053(1), 4.05.3(1)(e), 4.05.3(7). <br />c. Rule 2.053(4)(a) — A general plan and detailed design plan shall be submitted for each sediment <br />pond, impoundment, other treatment facility and diversion proposed to be constructed within the <br />permit area. Please provide detailed design plans for each postmining drainage channel. <br />d. Rule 4.053(1)(e) — channels must be designed, located, constructed, maintained, and used to <br />minimize adverse impacts to the hydrologic balance, and to be stable. Trapper has offered details <br />on how the channels might be constructed and maintained, but has not provided specific design <br />information. Please provide design information for each postmining drainage channel to include <br />the minimum channel dimensions and details of any required velocity reduction measures. The <br />dimensions and channel properties must be based on the anticipated runoff for each specific <br />watershed, based on watershed size, topography and cover; the design precipitation event; runoff <br />potential, etc. <br />e. Rule 4.053(7): <br />I. channel linings, including channel riprap, shall be designed using standard engineering <br />practices to pass safely the design velocities. Please provide design information for each <br />postmining drainage channel to include the minimum channel dimensions and details of <br />required velocity reduction. The dimensions and channel properties must be based on the <br />anticipated runoff for each specific watershed, based on watershed size, topography and <br />cover; the design precipitation event; runoff potential, etc. <br />ii. Freeboard shall be no less than 03 feet. Please provide details on the proposed channel <br />dimensions so that the Division can determine whether the designed channels maintain <br />the required freeboard. <br />iii. Trapper must submit the information required in Items (a) through (c) for all postmining <br />drainage channels to be constructed, completed, or reconstructed during the current <br />permit term. <br />f Trapper's Response: Trapper is still ivorking oni a response to this comment. We have <br />encountered problems with a consultant engaged to advise us oui this issue and the work is still <br />�Iot complete. <br />g. Division's Response: This item is still outstanding and will need to be addressed prior to the <br />approval of PR7. <br />24. Trapper did not submit designs for the three proposed sediment ponds that are shown east of the current <br />disturbance boundary, as required by Rules 2.053(4) 4.05.5, 4.05.6, and 4.05.9. Prior to any surface <br />disturbance east of the Deal, Middle, East Flume, and East Middle Flume watersheds, Trapper must <br />