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Kinetic testing is performed on samples which do not meet the ANP/AGP cutoff ratio used to <br />discriminate potentially acid generating and nonacid generating materials. The k)netic tests allow <br />the sample to be exposed to an environment highly conducive to accelerated sulfide oxidation <br />for many weeks. The results of that oxidation (should it occur) and any attendapt neutralization <br />are determined chemically. <br />2.3.2.2 Humidity Cell Testing <br />Kinetic testing of the tailings was performed using a humidity cell procedur(=. The tailings <br />sample is placed in a reaction vessel and exposed to three-day cycles of alternade moist and dry <br />air (oxygen saturated) at temperatures of 65-70' F or greater. After seven days the sample is <br />leached with water and the leachate analyzed. The whole process is repeated week after week, <br />normally for twelve weeks, until the sample has: <br />• become acidic (as characterized by persistent low pH values); <br />• 9S generated acid, but the acid has been neutralized by the AN)# of the tailings <br />and no further acid generation is occurring; <br />• ~ no sulfide oxidation or acid generation occurred and the ta~lirtgs remained <br />alkaline; <br />The analysis of the leachate from the humidity cell allows these three conditionslto be assessed. <br />The species analyzed - pH, conductivity (related to total dissolved species), sulfate, iron, acidity <br />and alkalinity -are indicative of acid generation and neutralization of acid. <br />In the case of the BMRI tailings material, both rinsed and unrinsed tailings samples have been <br />subjected to humidity cell testing. <br />• <br />to <br />