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DESCRIPTION OF THE ENVIRONMENT <br />Geology <br />The Marr Strip Mine is located in North Park, an intermountain valley bound to the north by <br />the Independence Mountain Fault, to the east by the Medicine Bow Range and Front Range, <br />to the south by Middle Park and to the west by the Park Range. There is a complex structure <br />of folding within the North Park Basin; the general structure is known as the North Park <br />Syncline. Within the this syncline there are numerous smaller folds generally striking to the <br />southeast in the permit area. The permit area occupies the western, steeper flank of the <br />asymmetrical Johnny Moore syncline, which plunges to the south. The McCallum anticline is <br />located just to the west, and parallels the permit area. The dip of the coal ranges from 45'- <br />86' to the east and northeast, averaging 68'. Two faults intersect the permit area along Bush <br />and Williams Draws. These trend from southwest to northwest and have a displacement of <br />100' - 150'. <br />The Marr Strip Mine produces coal from the Sudduth seam, a coal seam 36 ft.-75 ft. thick, <br />averaging 50 ft.. This seam is the lowest coal found in the 5,000 ft. thick Tertiary Coalmont <br />Formation. Shale overlies the Sudduth seam while a 50 feet thick fine-to-medium grain <br />sandstone lies between the coal and the underlying Pierre Shale. Quaternary alluvium of <br />sand, gravel, clay, dune sand and glacial till is found along the creeks and rivers in the area. <br />Geochemical Analysis of Overburden and Underburden <br />Kerr Coal Co. has drilled many holes within the permit area and conducted toxicity analysis of <br />overburden and underburden. A total of 67 samples were taken from 18 drill holes. <br />Dissimilar lithologies were sampled at 5 foot intervals and analyzed for potential toxicity. The <br />areal sampling density was a minimum of one hole every 1300 feet. Other drillhole sample <br />analyses were available from the USGS and the BLM for areas in and around the permit area. <br />Kerr sampled and interpreted the results using the published guidelines of the Wyoming <br />Department of Environmental Quality and the Montana Department of State Lands, <br />Reclamation Division. <br />Interpretation of the analysis does not show overall overburden or underburden toxicities. <br />Some of the analysis showed a few values that exceeded the suspect levels of either of the two <br />States. Levels for Nickel were marginally in the suspect range (Wyoming guidelines). <br />However, the overburden is alkaline, and nickel in the concentration ranges found at the <br />mine, as studies have shown, would not suggest plant or hydrologic toxicity problems with <br />respect for Nickel. Some sample analysis showed marginal potential toxicities for selenium. Of <br />the 54 samples taken 12 exceeded the suspect level (Wyoming guidelines). Of these twelve, <br />eight of the samples came from holes drilled with mud. This may suggest some contamination <br />Marr Strip Mine, C-80-006 7 December 9, 1992 <br />