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<br />overflow channel area and that mining will occur only during low flow times when [here is not <br />any runoff flowing through the azea. As requested in Item 2 above, please provide a specific <br />period of time (calendar dates) each year when mining will occur and when mining will be <br />excluded in this area. <br />9. The applicant indicates that barriers 150 feet in width will be left on each end of [he RRA to <br />maintain the integrity of the existing channel of the river, and that the barrier on the upper end <br />will have large boulders placed along the toe of the slope to prevent erosion of the bank in high <br />flow. As mentioned in Item 5 above, representative cross sectional designs for the barrier will <br />need to be submitted to the Division for review. Also, the applicant will need to explain why <br />large boulders will be used only at the upper end rather than throughout the entire length of the <br />barrier. <br />10. The applicant states that the estimated depth of mining in the RRA will be five feet. The <br />applicant will need to specify a maximum depth of excavation and elevation [hat will not be <br />exceeded during mining. The elevation not to be exceeded must not be any lower than the <br />bottom elevation of the low flow channel of the Colorado River. This information and <br />commitment will need to be based in part on a representative cross sectional survey of the entire <br />channel of the Colorado River in this area, ranging from north high banl: to south high bank. <br />Such representative cross sections will need to be submitted to the Division prior to a <br />recommendation for approval of the application or the applicant may commit to providing the <br />requested cross sections prior to any mining disturbance in the RRA. (The applicant will need to <br />discuss with the Division the number of cross sections needed to adequately represent the RRA). <br />Also, the applicant will need to commit to a method that will be used to verify such commitment <br />throughout mining and reclamation. As with similar operations, the Division will accept a <br />commitment from the applicant to conduct baseline and annual cross sectional channel surveys <br />and for the applicant to submit such results for review. Please address. <br />11. The depth of mining and elevation not to be exeeded in the RRA will also need to be based <br />on the projected bedload to be deposited in the excavation over a period of five (5) years, ie: the <br />applicant will need to provide infotmation, such as bedload studies or bedload projections, <br />adequate to demonstrate that the excavation can feasibly be reclaimed (filled in) over such <br />period. The Division highly recommends that the applicant consider a minimal depth of <br />excavation over the entire area, such as 1 or 2 feet, and then evaluate the ability the river channel <br />to fill in and reclaim itself. A commitment toward a minimal depth of excavation over the entire <br />area will enable the applicant to demonstrate a minimal impact to the river channel and will <br />enable [he applicant [o mine a[ a deeper depth in the future (via a technical revision to the mine <br />plan) once the ability of the river to reclaim itself is better known from on-going channel surveys <br />and monitoring. <br />12. The applicant indicates that if the RRA becomes unecomical to mine and it is still an <br />overflow channel then the area will be reclaimed to create a backflow area using materials in the <br />pit area. The applicant will need to provide specific plans or details of what the reclaimed <br />backflow area contours will be, the haul distance and volume of materials [hat will be needed for <br />backfilling, and the volume of backfilling and grading necessary to achieve such a phut. <br />