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Memorandum in Response to Notice of Determination of Designation Mining Operation (DMO); DRMS File Numbers <br />M-1977-416, M-1978-039 HR, M-1977-285, M-1980-055 HR, M-1981-021 and M-1977-032. <br />Ore at the these mines is stockpiled on the top of the waste rock areas and is then <br />transported to benison's White Mesa Mill (located near Blanding, Utah) for <br />processing as frequently as daily to weekly. Therefore, ore is typically not stored on <br />the surface at the mines for periods lasting longer than one week. All surface water <br />with the potential to encounter ore stockpiles is routed around the stockpiles and,/or <br />contained in temporary sedimentation basins that are designed to contain the 100- <br />year, 6-hour frequency storms. Based on this information, a geochemical analysis of <br />ore is not likely to be necessary; however, one representative composite ore sample <br />will be analyzed and results will be provided to the Division. Collection will occur <br />once this procedure has been agreed upon by the Division. Results of this analysis <br />will be provided to the Division within one month of their collection. <br />Environmental Pathway Analysis <br />Denison proposes the following programs for evaluating potential contamination of <br />surface water, groundwater and soils at the Sunday, 'West Sunday and Topaz mine sites. <br />Current surface water protection at each of those: mines includes diversion of off site <br />surface water around the surface facilities, collection of surface water that falls <br />directly on the surface facility, and containment of surface water in temporary <br />sediment basins. An engineered drainage study of these .mines is currently being <br />prepared and will be provided to the Division to ensure that appropriate best <br />management practices and engineered, structures are beingused at the mines in order <br />to be protective of surface water in the_area. <br />As discussed previously, groundwater encountered at these mines is minimal. No <br />groundwater is brought to the surface; therefore, these mines are all zero discharge <br />facilities. Pending the results of this data collection, a groundwater pathway analysis <br />will be discussed further.:during Elie°Phase 2'EPP preparations. <br />Soil samples will be taken from undisturbed and unaffected areas near the toe of the <br />waste rock areas (three each, nine ~ amples total) to determine their chemical <br />composition, as it pertains to existing constituents of concern in the soils to establish <br />background, and also to evaluate its geochemical adsorption potential for constituents <br />of concern. 'In addition to the chemical composition of the soils, the physical <br />characteristics of these soils will be evaluated and a transport model will be <br />developed in an effort to show the realistic potential for constituents of concern to be <br />transported into soils and groundwater beneath the waste rock areas. This analysis <br />and transport model will be provided to the Division within six months of approval of <br />the process by the Division. <br />In addition to providing information necessary to prepare the EPPs for the mines, it is <br />hoped that the foregoing sampling will provide enough information to enable Denison <br />and the Division to determine whether or not toxic or acid-forming materials will be <br />exposed or disturbed in quantities, sufficient to adversely affect human health, property <br />or the environment, which is one of the criteria that must be addressed under Rule <br />7.2.6(1). <br />5 <br />