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capacity has been designed to accommodate a 100-year flood event, approximately 60 <br /> cfs. Attachment C, Sheet 28, show several designs of a drainage structure for diversion <br /> of the seep and rain water runoff; Cotter currently intends to proceed with the 5-inch <br /> concrete riprap ditch design. <br /> Comment No. 14 - Pursuant to Rule 6.4.21(6)(b), please submit a plan or narrative that <br /> describes how the excavated alluvial fill will be handled to ensure that the affected lands will <br /> be reclaimed and returned to the post-mining land use. <br /> Response: Cotter intends excavate alluvial fill without stockpiling material. Instead, <br /> excavated alluvial fill will be placed directly into haul trucks for transportation to the <br /> WRPs, where it will be placed and graded. Cotter will grade the excavated alluvial fill on <br /> the WRPs in a manner that precludes runoff-induced erosion of the WRPs. Furthermore, <br /> a soil cap and vegetated cover will prevent excavated materials from migrating off the <br /> WRPs. <br /> Regarding storm water management(SWM), Cotter's final design plans, will present the <br /> necessary SWM structures to prevent discharges to Ralston Creek. Such SWM structures <br /> may include: settling basins with dewatering bags, aggregate vehicle tracking control <br /> with wash rack, sediment control logs, and stockpile protection with silt fence (if <br /> necessary). Cotter will also utilize earth dikes and drainage swales, where necessary. <br /> Comment No. 15 - Please provide the Division with an updated Reclamation Plan Map <br /> which depicts the final configuration of the WRPs and which shows only the facilities which <br /> will remain upon release of the permit. The Reclamation Plan Map shall conform to the <br /> mapping criteria in Rule 6.2.1 and Rule 6.4.6. <br /> Response: At this point, Cotter is uncertain which structures will remain after the permit <br /> is released. The intended configuration of the WRPs is in the TR-23 submittal and <br /> Attachment C. It is not possible to show the final WRP configuration since we do not <br /> know the final excavation volume. When the final WRP configuration and remaining <br /> structures is determined, a Reclamation Map will be submitted that will conform to the <br /> mapping criteria in Rule 6.2.1 and Rule 6.4.6. <br /> Comment No. 16 - Table 4-1: Cost Estimate of Alluvial Fill on WRPs, contains costs for the <br /> collection and analysis of soil and water samples. Please specify the analyses which will be <br /> performed and indicate when the results will be provided to the Division. If this information <br /> is already contained in the permit file,then please specify where it may be found. <br /> Response: Cotter will be analyzing soil and water for uranium by inductively coupled <br /> plasma—mass spectrometry(ICP-MS) and onsite, hand-held gamma scan equipment. <br /> Based on these measurements, Cotter intends to excavate materials that exceed the <br /> gamma limit of 22µR/hr. <br /> Cotter will provide the results of the excavation along with final gamma exposure <br /> 2016-11-07 Response to TR23 Adequacy Review 6 <br />