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<br />• <br />• <br />Section 779.14(a) Continued. <br />Rule 2.04.6 <br />a volumetric basis had a value less than 0.20 ppm. The Montana <br />Guidelines, generally the most stringent, established 40 ppm as the <br />suspect level for copper and all samples analyzed fell well below this <br />limit. Thus, no deficiency or toxicity problems should be encountered <br />with copper once overburden materials are thoroughly mixed during the <br />mining process. <br />Manganese (Mn). A total of 54 Kerr samples and 66 USGS samples were <br />analyzed for manganese. The mean DTPA manganese value was 12.66 ppm with <br />a range from 0.20 to 55.70 ppm for the Kerr samples, and 4.50 ppm with a <br />range of 0.64 to 52 ppm for the USGS samples. The weighted mean value was <br />8.41 ppm for the Kerr samples and 3.54 ppm for the USGS samples. Ludwick <br />(1976) reports that concentrations above 1.0 ppm are adequate for plant <br />growth and only eight (8) of the samples analyzed, representing 2.36 <br />percent of the overburden volume had manganese values less than 1.0 ppm. <br />No potential deficiencies or toxicities are expected. The Montana <br />Guidelines set the suspect level at 60 ppm. Only one (1) sample is above <br />this limit. On a volumetric basis only 0.17 percent of the overburden can <br />be considered as above the suspect level. Normal mining operations will <br />result in sufficient mixing and dilution to eliminate any potential <br />adverse revegetation impacts from limited high Nn values. <br />Nitrate (N0; N). A total of 54 Kerr samples were analyzed for nitrate <br />nitrogen. The mean value of nitrate for the samples collected was 4.57 <br />ppm with a range from 0.70 to 12.80 ppm. According to Ludwick (1916), <br />these values would be tow with respect to agronomic suitability and <br />fertilizer may need to be added. Mith respect to possible toxicity, none <br />of the samples had nitrate concentrations above the 20 ppm suspect level <br />set forth in the Montanan Guidelines. <br />Cadmium (Cd). A total of 54 Kerr samples and 50 BLM samples were analyzed <br />for cadmium. For the Kerr samples, the values of DTPA cadmium ranged from <br />less than 0.01 ppm to 0.68 ppm with a mean of 0.29 ppm. The BLM samples <br />ranged from 0.02 ppm to 0.16 ppm with a mean of 0.05 ppm. A weighted <br />average of the Kerr samples with weighting based upon specific thicknesses <br />of strata represented by each sample was 0.26 ppm. None of the samples <br />779-20 a <br />sed - Aori 1.1990 <br />