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RECEIVED <br />FEB 2 7 2007 <br />Division of Keclamation, <br />Mining and Safety <br />A paste test is a quids way to determine ii your sample does not have any neutralizing <br />potential. Add about 0.25 g of sample to a watch glass. Add a drop or two of D.I. H,O until a <br />thick paste is formed. Now dip a piece of pH paper in the paste and let ft set there for a few <br />minutes. H the pH of the paste teat is below 3.5, then the add neutralizing potential of the <br />sample is zero. If the pH testis above 3.5, the sample may contain carbonates or other <br />buffers that will contribute to the neutralizing potential of the sample. If so, determine the <br />neutralizing potential in according to the procedure in step 2. <br />2. Accuretely weigh three or four samples of your unknown. Each sample should weigh between <br />0.25 and 0.358. Record the masses to 0.00018. Transfer your samples to a 250 mL beaker. <br />Pipet 5.00 mL of a standardized 0.1 M HCI solu8on. AUow the reaction to go for about 20 <br />minutes, mixing occasionally. Bring the volume to about 100 ml in your beaker by adding D.I. <br />water. Heat dais sdution to boiling to drive off C02. Let cool, then titrate using a pH meter and <br />the standardized 0.025 M NaOH. Determine the add neutralizing potental of your unknown <br />and report the findings as mlllieyuivalerrts H'/100 g sample (or miltimWes of H'/100 g sample). <br />Summary <br />Determine the net add producng potential of your mine overburden sample. Express the results in <br />meq H'/100 g of sample. In actual practice, the net add producing potential of mine overburden is <br />expressed as tons of CaC03 required to neutralize 1000 tons of material with the intention that the <br />mine overburden would be amended with CaCOa to a depth of 1 foot <br />References <br />1. Sobek A.A., Schuller W.A., Freeman J,R. and Smith R.M. (1978), FieM and laboratory methods <br />applicable to overburden and minesoils, EPA 600/2-78-054, 203 pp. <br />