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Table 13 summarizes the results of the analyses of the wall scrapings. The complete <br />laboratory report including methodology is given in Appendix E. Wall scrapings from <br />below B-level (nominal elevation of 12,250 feet) all had a paste pH of greater than <br />4.5. A paste pH represents a minimal amount of water added to a sample and will <br />typically yield a worst case pH. A paste pH of greater than 4.5 indicates a very low <br />potential for acid generation. <br />The three wall scrapings from B-level all had a paste pH of less than 4.0 and <br />warranted further evaluation. Samples 1-5 were all mixed with a weakly buffered <br />solution which simulated the measured buffering capacity of Terry Tunnel water. The <br />solution resulting from sample 5 Ifrom B-level- showed a pH of 5.7 after mixing with <br />100 parts of weakly buffered water to one part of sample. The solutions resulting <br />from sample 4 showed a pH of 6.7 after mixing 1000 parts of weakly buffered water <br />to one part of sample. The actual ratio of water filling the tunnels to volume of wall <br />coatings is greater than 1000 to 1 even if only the immediate vicinities of the wall <br />coatings are considered. The solution resulting from sample 3 had a pH of 4.9 after <br />mixing 10,000 parts of weakly buffered water to one part of sample. The mineral <br />encrustation where sample 3 was taken covered an area of only 2 by 6 feet, so only <br />a small volume of mine workings would have to be flooded to counteract the effects <br />of this zone. If the full volume of the mine is considered, the acid-generating capacity <br />of the observed wall scrapings is insignificant. <br />•unnYlwP'~Ir~nl: I51}Mr199J Rpt 70 <br />III SIf110(1 HYDRO-SERRCH <br />