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Overburden and Underburden Analyses <br />Two samples were taken late in 1981 from the floor and the roof <br />of the C-Seam in the existing Bear operation. The two samples <br />analyzed were basically classified as shale with some small <br />amount of interbedded coal or carbonaceous shale, The results of <br />the detailed analyses performed on these samples are set forth in <br />Table 4, Overburden and Underburden Analyses. In mid 1989 sam- <br />ples were taken from the B-Seam floor coal, the B-Seam roof and <br />the temporary waste storage piles #1 and #2. The results of the <br />analyses performed on these four samples are presented in Table 4 <br />Page 2.04-24a <br />Although it is anticipated that no groundwater will discharge <br />from the mine entries, the following interpretive summary was <br />developed to compare the analytical results obtained from these <br />samples with established recommendations so potential problems in <br />possible post-mining water quality could be identified. All <br />results were compared with the suggested guidelines of the Wyo- <br />ming Department of Environmental Quality, Land Quality Division, <br />Guideline No. 1 (1981) or Montana, Department of State Lands <br />Guidelines. <br />Electrical Conductivity. Values of 4.9 and 10.5 were found in <br />the samples taken from the top and bottom material of the C-Seam. <br />The B-Seam floor coal, B-Seam roof and the temporary waste piles <br />#1 and #2 showed Electrical Conductivity values of 0.53, 2.16, <br />• 2.84 and 2.72 respectively. The weighted electrical conductivity <br />value for the area is approximately 7.7 mmhos/cm. This average <br />shows that the E.C. values for the material should pose no prob- <br />. lems. The value of 10.5 mmhos/cm indicates that there is a <br />slightly high level of salinity; however, because of the apparent <br />lack of any groundwater in the area of planned mining, no prob- <br />lems are anticipated. <br />pH. The values of pH found in the top and bottom material of the <br />C-Seam are 5.5 and 7.5. The pH values for the B-Seam floor, the <br />B-Seam roof and the temporary waste piles #1 and #2 are 7.7, 9.0, <br />8.5 and 8.5 respectively. According to the suitability system <br />proposed by the Wyoming Land Quality Division, both samples fall <br />in a suitability range of pH values. The value of 5.5 found in <br />the C-Seam top material may occur from some of the coal mixed <br />with the shales; therefore, this pH value may be a result of <br />slightly higher organic matter levels in the sample. No poten- <br />tial problems of acidity are expected. <br />• 2.04-22 <br />Revised June 29,1990 <br />