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Memorandum 2 February 11, 2010 <br />Geochemistry Review Ruby Trust Mine <br />http://www.epa.gov/waste/hazard/testmethods/sw846/pdfs/1311 pdfl. The SPLP uses an extraction fluid <br />with pH 5.0 for sites west of the Mississippi River (Section 5.4.2 of the Method 1312 description, which is <br />available at: http://www.el)a.gov/waste/hazard/testmethods/sw846/pdfs/1312.pdf). An extraction fluid pH of <br />2.88 would certainly leach more metals than an extraction fluid of pH 5.0, so the regulatory criteria of Tables <br />5 and 8 are likely elevated with respect to what would be leached from the same material using the SPLP <br />method extraction fluid. Please provide the rationale for why EPA Regulatory Levels derived from the <br />TCLP method would be relevant to SPLP leachate, given the substantially different pH of the two extraction <br />fluids deployed for each test. <br />Additional DRMS comment: DRMS has primacy over EPA at mining sites in Colorado for all water quality <br />concerns with the exception of Underground Injection. As an implementing agency for water quality standards <br />adopted by the Colorado Water Quality Control Commission (WQCC), DRMS will enforce the regulatory <br />criteria presented in WQCC Regulation 41 for ground water and, as needed., Regulation 31 for surface water. <br />The criteria of those Regulations are also applicable to accelerated weathering test leachate. <br />Rock Samples: Several tables show data for three samples collected in 2009: RT-SS-001-121009, RT-SS- <br />002-121009, and RT-SS-003-121009. Page 2 states that "samples of waste rock were collected by Karmen <br />King in 2009." <br />DRMS Comment: Please confirm that the three samples listed above are all indeed waste rock. <br />Table 1: The concentration of Nitrate/Nitrite in the SPLP leachate from the 2008 Tailings sample is quite <br />elevated. <br />DRMS Comment: Is historical blasting on site the likely source of the Nitrate/Nitrite? If blasting did not <br />occur on site historically, please provide an explanation as to the possible source of the elevated <br />Nitrate/Nitrite. <br />Table 3: Analytes. <br />DRMS Questions: On what materials were the carbonate and bicarbonate analyses conducted and what <br />were the standard methods or procedures used? <br />Please explain the Chloride (1312 DI), Sulfate (1312 lDI), and Conductivity (1312 DI) <br />analyses. Were these measured on the 1312 extraction fluid before the SPLP agitation <br />procedure? <br />Was Total Alkalinity measured on the post-agitation extract? <br />Table 4 - ABA Parameter Results using Total Sulfur and Pyritic Sulfur: Please explain why, for a given <br />sample, the reported Acid Neutralization Potential for "ABA Parameters Based on Total Sulfur" is different <br />than the reported Acid Neutralization Potential for "ABA Parameters Based on Pyritic Sulfur." Are not both