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respond. <br />Drainage Designs -The applicant indicates on page 8 that a drainage diversion will be placed as shown <br />on Exhibit C2-B to divert water azound this site and back to the original drainage course; and that surface <br />water from disturbed azeas will be diverted on the south to a settling basin prior to being released back into <br />the natural drainage system. The applicant further indicates on page 13 that several drainages will be <br />recreated during the grading process to drain water from the affected azea. Review of Exhibits C2-B & <br />C2-C indicates that diverted waters from undisturbed azeas will be merged with treated waters from <br />affected lands prior to being dischazged offsite towazd North Clear Creek; that there is no definitive <br />treatment system for stormwater passing over the quarry azeas and that there is insufficient information to <br />verify that all waters dischazged offsite will be dischazged safely in a controlled manner so as to minimize <br />the potental for offsite erosion. Further, there is no supporting watershed infomuition and/or hydraulic <br />computations to verify the adequate sizing of sediment pond stmctures, culverts, or drainage channels <br />treating or conveying runoff waters from the contributing watershed. (In most cases, it is desirable that <br />runoff waters from upland, undisturbed areas be diverted azound the affected lands and not merged with <br />treated or process waters from the affected land. Further, Best Management Practices should be employed <br />in treating stormwater runoff passing over affected lands prior to release downstream and/or offsite). <br />Please address. <br />Drainage Design Inputs -Consideration should be given to the size and capacity of natural drainage <br />features in the design of shuctures used to convey runoff waters from an undisturbed, contribufing <br />watershed. Structures used to treat or convey runoff waters from a disturbed, affected azea will need to be <br />sized to handle the peak velocity and volume from a design storm event in a controlled manner. Permanent <br />structures to be left in place during final reclamation will need to be designed based on a 100-yeaz storm <br />event. Temporary structures to be removed during final reclamation will need to be designed based on a <br />10-yeaz, 24-hour storm event, or a 2-year, 6 hour storm event, whichever is greater. Please address. <br />Blasting Plan -Allen Sorenson of the Division will provide review comments regazding the applicant's <br />proposed blasting plan and documentation of blasting procedures, per Rule 6.4.4(1). Mr. Sorenson's <br />comments will be forwazded to the applicant as soon as they become available. <br />Uranium Mineralization - A number of objectors have expressed concer over potential impacts from <br />uranium that maybe exposed via drilling and blasting at the MMRR Quarry. Such impacts may result <br />from uranium from airborne dust or stormwater runoff. The Division requests that the applicant address <br />the potenfial"foi• adveiseitnpacts fo humanfiealfh,-and-the environment inblu3ing vegetation, wrldIife, and <br />surface water quality of North Cleaz Creek. The Division requests that the applicant address the potential <br />for mineralization of uranium by implementing one of the fallowing options: <br />Option 1-Detailed Geologic Assessment :Prior to drilling and blasting as specified in the mine plan, <br />the applicant will submit for Division review and approval a detailed geologic assessment of the presence, <br />extent, and concenfrafion of uranium within the affected land to be removed and/or exposed during mining <br />activities. Such assessment should assess the toxicology of uranium to the human and environmental <br />receptors, identifying in particulaz the level above which uranium and radiation regulations would require <br />dust control, and/or the level above which water quality regulations would require dust control to minimize <br />impacts to surface water quality. If needed, the assessment should propose uranium monitoring, and a <br />containment and control plan to be employed during mining and reclamation. Such monitoring, <br />containment, and control should include mitigation measures to minimize potential impacts to human <br />health and the environment, and containment and control measures to ensure compliance with all <br />applicable Federal, State, and local regulations for dust emissions and surface water contamination. <br />