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These results provide an indication of the total amount of a metal within a given <br />material. The results can be compared to EPA soils/solids thresholds developed for the <br />protection of human health (EPA, 2010). This comparison is strictly a screening tool and <br />not a definitive expression of the risk setting. In addition, the solid results (in mg/kg) <br />can be interpreted with the SPLP result (in mg/L) to provide a cursory indication of <br />solubility (or partition from solid to solution such as the development of a Kd value). <br />In addition to the metals content analysis, the 2009 samples were also analyzed for ABA <br />parameters, paste pH and forms of sulfur; which all serve to characterize the acid <br />generation/acid neutralization potential of the solids material. The interpretation of <br />these results has been described within various literature resources (i.e. Williams and <br />Schuman, eds., 1987) and summarized within Table 7. <br />Water Analysis Interpretation Methods <br />Water samples have been taken at the permitted point of discharge from the Ruby Trust mine <br />since 2007 (third quarter). The suite of analyses was defined by the Colorado Department of <br />Public Health and the Environment (CDPHE) based upon the receiving system (Sneffel's Creek) <br />compliance criteria. The point of discharge is located immediately at the mine portal which <br />captures the water released from the underground workings of the mine. Therefore, the water <br />quality of this water is a reflection of the hydrogeochemical setting associated with the mine. <br />The pH results have ranged from 6.9 to 8 indicating a circum-neutral water quality setting. <br />Regulatory Levels <br />EPA's regulations establish two ways of identifying solid wastes has hazardous (potentially <br />toxic) under the Resource Conservation and Recovery Act (RCRA) which sets many of the <br />standards for definition of hazardous constituents. A waste/material may be considered <br />hazardous if it exhibits certain hazardous properties (characteristics) or if it is included on a <br />specific list of wastes EPA has determined are hazardous (listing a waste as hazardous) because <br />they have been found to pose substantial present or potential hazards to human health or the <br />environment. Mine waste is exempt from regulatory definition as a `hazardous waste'. <br />However, the metals encountered in mine products are considered `potentially toxic' or harmful <br />to the environment if they exceed certain thresholds and are released to the environment. As a <br />result, regulatory agencies are tasked to assist in the management of these potentially harmful <br />materials in order to releases to the environment. <br />Since metals are ubiquitous, and some are common elements/essential elements; the EPA has <br />developed threshold criteria for comparative purposes to determine if the metal is a toxicity <br />concern. If the measured concentrations of the metal occur below the threshold, the material is <br />considered non-harmful for that element. If the material contains concentrations exceeding the <br />threshold, then there is the potential for harm to human health or the environment and further <br />evaluation or proper disposal is warranted. For instance, EPA regulates soil containing mercury <br />.......... _.. ............. . ......... _... . <br />61 Page