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<br />Section 779.14(a) Continued. Rule 2.04.6 <br />Kerr overburden samples of 7.84 and mean groundwater pH of 1.07. <br />Furthermore, the acid-base potential is very low (refer to the discussion <br />on acid-base potential in this section). These conditions can be related <br />to Gingham's study, where acid soils were treated with lime to increase <br />the pH values from 5.2 to 6.7. The results of that study include the <br />following observations: "In the limed acid soil, levels of Ni and Zn as <br />large and possibly larger than 80 and 200 micrograms per gram (ppm), <br />respectively, did not reduce grain yield". Greenhouse studies conducted <br />by Or. Bob Heil of CSU in conjunction with the 8LM EMRIA project showed <br />plant tissue concentrations of nickel to range from less than 1 ppm to a <br />maximum of less than 5 ppm. He concluded that these values were <br />acceptable from a plant growth standpoint. The results suggest that no <br />toxicity problems should be encountered with respect to nickel. <br />• pal. A total of 67 Kerr samples, 66 USGS samples and 50 BLM samples were <br />analyzed with respect to pH. Values of pH for the Kerr samples ranged <br />from 6.5 to 11.4 with a mean value of 7.84, indicating relatively alkaline <br />materials. Two (2) samples were above the 9.0 limit set forth in the <br />Montana Guidelines and none was less than 5.0. These two (2} high pH <br />values, 10.9 and 11.4 from Hole 28-19-16C are most likely the result of <br />sampling or analysis error. Of the 66 USGS samples only one (1) sample <br />(1.52%) exceeded the pH value of 9.0. The mean for the USGS samples was <br />1.78 with a range of 5.7 to 9.1. The alkaline pH values will decrease the <br />potential for dissolution of several elements, zinc, iron and nickel in <br />particular. Sample pH values indicate no significant potential for <br />development of acidic or alkaline conditions in the spoils or hydrologic <br />system. For further information, refer to the discussion in this section <br />on acid-base potential. <br />Electrical Conductivity (EC). A total of 67 Kerr samples and 55 USGS <br />samples were analyzed with respect to EC. Values of EC for the Kerr <br />samples ranged from 0.20 to 11.3 mmhos/cm with a mean value of 1.81 <br />mmhos/cm. The mean value for the USGS samples was 1.59 mmhos/cm with a <br />range of 0.41 to 13.1 mmhos/cm. Of all the samples analyzed, none had an <br />EC value above the limit of 16.0 mmhos/cm set forth in the Wyoming <br />Guidelines. <br />