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Within this syncline there are numerous smaller folds generally trending southeast in the permit area. The permit azea occupies the western, steeper flank of the asynunetrical Johnny Moore syncline, which plunges to the south. The McCallum anticline is located just to the west, and pazallels the permit azea. The dip of the coal within the permit area ranges from 45° to 86° to the east and northeast, averaging 68°. Two faults intersect the permit azea along Bush and Williams Draws. These strike from southwest to northeast and have a displacement of 100 to 150 feet. The Marc Strip Mine produced coal from the Sudduth seam, a seam ranging from 35 to 75 feet in thickness, averaging 50 feet. This seam is the lowest coal found in the 5000-foot-thick Tertiary Coalmont Formation. Shale overlies the Sudduth seam, while a 50-foot-thick, fine-to-medium grained sandstone lies between the coal and the underlying Pierre Shale. Quaternary alluvium of sand, gravel, clay, dune sand, and glacial till is found along the creeks and rivers in the azea. Geochemical Analysis of Overburden and Underburden Kerr Coal Company drilled many holes within the permit area and conducted toxicity analysis of the overburden and underburden. A total of 67 samples were taken from 18 drill holes. Dissimilar lithologies were sampled at five-foot intervals and analyzed for potential toxicity. The azea] sampling density was a minimum of one hole every 1300 feet. Other drill hole sample analyses were available from the USGS and the BLM for azeas in and azound the permit area. Kerr sampled and interpreted the results using the published guidelines of the Wyoming Department of Environmental Quality and the Montana Department of State Lands, Reclamation Division. Interpretation of [he analysis indicated no overall overburden or underburden toxicities. Some of the analyses showed a few values that exceeded the suspect levels identified in the guidelines from one or the other of the two States. Levels for nickel were marginally in the suspect range (Wyoming guidelines). The overburden was found to be alkaline, however, and nickel in the concentration ranges found at the mine would, according to certain studies, not suggest plant or hydrologic toxicity problems. Some sample analyses showed marginal potential toxicities for selenium. Of 54 samples taken, 12 exceeded the suspect level (Wyoming guidelines). Of these 12 samples, eight came from holes drilled with mud. This was believed to suggest that some contamination had occurred. The remainder of the samples that showed elevated levels represents 12.7 percent of the overburden volume. Studies conducted by the federal government show that up to 20 percent of potentially toxic material in a truck-and-shovel operation would be diluted to acceptable levels. Twenty-three of the samples exceeded the Montana guidelines suspect levels for molybdenum. Wyoming does not have a suspect level for molybdenum. Studies indicate that a field occurrence of toxicity does not exist with respect to molybdenum. All surface water and groundwater samples evaluated by the mine aze below the detection limit. SAR values in 38.6 percent of the samples were above the suspect level of 15 described in the Wyoming guidelines. The weighted average value is 8.74. Many of the samples were con- taminated with drilling mud, drilling foam, or other drilling fluid. Kerr cited a study that showed that drilling fluids dramatically increase SAR values above samples taken from highwall or drilled with air. None of the drillholes were drilled using air; therefore, all samples were deemed Marr Mine Permit Renewal 04 11 January, 2002 -5-