2018-05-31_REVISION - C1982056 - Laserfiche WebLink

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RN07 Page 14 5/30/18 Response: - The referenced water treatment facility and associated ponds have been modified and upgraded over time to meet changing operational needs. In 2006, the existing caustic soda (sodium hydroxide) treatment system was replaced with an electro-coagulation (EC) system, approved under MR06-207. A metal building housing the EC System was added, along with some piping and power-distribution modifications, and the trailer that previously housed the caustic soda treatment system was removed. These changes were addressed by revised permit text, changes to Map 24, and the addition of Exhibit 49G, which includes design information and drawings. One of two dewatering boreholes at this location collapsed and could not be recovered, so the existi ng inactive Fish Creek Ventilation Borehole was converted to a replacement dewatering borehole. This conversion, approved under MR07-216, involved installation of a pre-fabricated building and piping and power-distribution modifications. These changes were addressed by revised permit text, changes to Map 24, and the inclusion of additional design information and drawings in Exhibit 49G. In 2016, a flocculent feed system was added to increase system efficiency and flexibility (approved under MR16 - 298). This system was installed within the existing EC building and required no changes to the facility. Both the permit text and Exhibit 49G were revised to include information on the new system. Resolved 42. Exhibit 8Q is referenced in the Table of Contents as: 8Q Pond T Certification. However it provides important information regarding impoundment design specifications, hydrology and soils, rather than Pond T as-builts. Please address the following: a. Please update the table of contents to reflect a more accurate title for Exhibit 8Q, such as for example: Impoundment Design Specifications, Hydrology and Soils b. Please inform DRMS what exhibit addresses Pond T stage storage and as built information. If there is no such exhibit, please provide stage storage information and as built designs and cross-sections for Pond T. Response: - Exhibit 8Q specifically states that it is a P.E. Certification for Ponds H, E, and T, and provides related information. It is important to note that Pond T, and all of the sedimentation structures (Ponds A through T, excluding I) associated with the Energy Fuels Eckman Park Mines and Mines 1, 2, and 3, and subsequently transferred to the Foidel Creek Mine Permit (see previous response to Comment 39) were designed and permitted under the Interim Program Regulations (prior to approval of the Colorado Program). As such, design information for these ponds may not be totally consistent with the current regulatory requirements, however, unless the ponds have been modified they are “grandfathered-in”, so the existing design information is considered adequate. Exhibit 8Q does reference the Leonard Rice Consulting Water Engineers sedimentation pond design information summary, (Plate 1) provided in the PAP as Exhibit 8P, which includes the basic required des ign information for Pond T and the other remaining Mine sedimentation structures. DRMS May 2018 Response Please update the table of contents to reflect a more accurate title for Exhibit 8Q 43. For the Fish Creek Tipple Pond, DRMS was unable to locate as-builts and stage-storage information. Please inform DRMS what exhibit shows the cross section and stage storage information for the Fish Creek Tipple Pond. If this information is not in the permit, please provide cross-section, as-built and stage-storage information for the Fish Creek Tipple.