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Fr_1TASCK <br /> Denver, Inc. <br /> When sulfur speciation is not available, such as is often the case for LECOT'A data collected as part <br /> of project operations, AGP is typically conservatively calculated using the assumption that all <br /> sulfur in the sample contributes to the AGP according to Equation 3.1. In some cases,only sulfide- <br /> sulfur is used to calculate AGP, but this approach is not conservative and can underestimate AGP <br /> in the presence of acid-sulfate minerals. <br /> 3.1.1.3 Acid-Neutralization Potential <br /> The acidity that is released through the oxidation of pyrite may be neutralized by calcium <br /> carbonate. As shown in Equation 3.2 below, the dissolution of 1 mole of calcium carbonate can <br /> neutralize up to 2 moles of acidity. <br /> CaCO3+ 2H+-> H2CO3 + Ca2+ (3.2) <br /> The ANP of the Phase I samples was measured by titration as per the Nevada Modified Sobek <br /> method (NDEP 2015). A sample of 1.0, 2.0, or 5.0 grams (g) was used, depending on the rating <br /> determined by a "fizz"test conducted on a 0.5 g split of the sample. Samples were pulverized to <br /> less than 250 micrometers (µm) (minus-60 mesh) and one or two drops of HCI was added to the <br /> 0.5 g split, after which the "fizz" was assigned a rating of none to weak (5 g of sample used), <br /> moderate (2 g of sample used), or strong(1 g of sample used). After determining the appropriate <br /> sample size, 50 milliliters (mL) of 0.5 normal HCI was added to the sample and the sample was <br /> heated to near boiling to allow the reaction to complete.The sample was then bulked to 125 mL <br /> with deionized water and allowed to cool.The siderite correction method was applied to address <br /> the potential effect of the hydrolysis of iron from siderite.The method involves adding hydrogen <br /> peroxide to the sample to encourage iron and other metal ions to hydrolyze prior to the ANP <br /> titration so that acidity related to the hydrolysis of metal ions contained in carbonate minerals is <br /> accounted for. The sample was then titrated with 0.5 N NaOH to reach the endpoint pH of 8.3. <br /> The ANP was then calculated as the difference between the equivalents of HCl added initially and <br /> 12 <br />