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features from being swept off-site. The location of the surface milling components is shown <br />within Map E.1, Exhibit E and labeled as the 'Proposed Surface Milling Operation'. <br />The milling components underground will serve multiple purposes for the mining efforts. As <br />shown in the Conceptual Site Diagram (Figure C.2) the mill equipment occurs at an elevation of <br />10,844 ft. The underground milling equipment is located adjacent to the transformer station, <br />shops and explosive storage (all underground). The actual mine workings are below these <br />features and occur at elevations ranging from 10,680 ft to 10,730 ft (refer to Table C.1 for a <br />summary of Ruby Trust mine feature elevations, and Figure C.2 for a conceptual depiction of the <br />relationship between the underground workings). The mine-workings were surveyed by Ruby <br />Trust staff in order to project future activities. A summary of a portion of these workings is <br />provided in Figure C.3. Figure C.3 depicts the low points in these workings where pumps are <br />used to draw-down groundwater in order to enable mining activity. This water is piped to the <br />portal and released via the CDPS permitted discharge. The measured underground water levels <br />at these points are 10,688 and 10,687 ft. <br />The proposed subgrade repository will be an historic 'crosscut' (by definition a crosscut does <br />NOT contact mineable material but only serves to create an access to mineable material <br />therefore this feature does not traverse a geologic setting that would contribute acid- or toxic- <br />forming substances) that occurs approximately over 100 ft above the static water level within <br />workings that contain little to no ambient moisture. In order to contain the subgrade materials, <br />the repository will be comprised of a bulk-head and partial geotextile liner enabling the capture <br />of decanted water (at the low end, immediately adjacent to the milling equipment) to be <br />recycled into the ball mill thereby eliminating a large portion of potential leachate water from <br />the subgrade ore. Any leachate water not recycled into the system that is created from the <br />repository would likely travel paths of least resistance into underlying mine features which <br />capture, pump and release water via the permitted point discharge (CDPS permit) (refer to the <br />Conceptual Site Diagram in Figure C.2). <br />b) Tailings Characteristics: Geochemical characterization of the solids portion has been previously <br />accomplished by the prior operator (C. Ponchak, 2008). As per DRMS direction, a sample of ore, <br />waste rock and tailings was collected and analyzed using SPLP methods. The results were <br />summarized and interpreted within Attachment C.I. The results indicate that the anticipated <br />tailings (subgrade ore) would be relatively inert (do not contain acid-forming character) and <br />contain minimal toxic-forming elements. Since the materials contain little to no acid-character, <br />the likelihood of any subgrade ore to leach toxic-forming constituents is very low. Furthermore, <br />since this material is'subgrade' as a result of the milling activity, there are severely diminished <br />levels of metals present to begin with. <br />Attachment C.1 provides a thorough analysis of solids samples collected from the mine that <br />reflect ore, waste rock and potential tailings (subgrade ore). The geochemical results from <br />11