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Conformably overlying the Iles is the Williams Fork Formation. The lower unit of the Williams Fork Formation is a series of interbedded shales, sandstones, sandy shales and coal. The middle coal group contains the seams of economic importance. Lowermost is the Wolf Creek coal, which is split into an upper and lower unit. The lower seam is about 16 feet thick, while the upper is about 7.5 feet thick. This coal lies too deep within the permit area to be mined by surface methods. 100 feet above the Wolf Creek coal is the Wadge coal. The two seams are separated by interbedded sandstones, shales, siltstones and thin coals. The Wadge coal seam is the most continuous in the area. The outcrop strikes about north-south, and dips 8 to 14 degrees. The Wadge is also split into upper and lower seams. The lower is two to three feet thick, and is separated from the 10 foot thick upper seam by two to five feet of shales and sandstones. The principle seam to be mined is the Wadge coal seam. Overlying the Wadge is about 560 feet of sandstones, shales, and coal, including the Lennox Coal Seam, which has been eroded away in places. Peabody will mine the Lennox where economical as it occurs in overburden above the Wadge mining areas. Overlying this lower unit of the Williams Fork Formation is the 130 feet thick Twenty Mile Sandstone. The upper most unit of the Williams Fork Formation consists of interbedded sandstones, shales, and thin coals. The applicant has submitted detailed analysis of the geochemicaT characteristics of the over and interburden found in the Seneca II-W Mine permit area. The parameters which were sampled for were agreed upon by the Division, OSM and Peabody Coal Company during meetings held in 1980 and 1981. Parameters sampled are listed in the permit application Volume 2, Tab 6, Pages 6-9 and 6-10. The permit application (Volume 2, Tab 6, Page 6-11) states that these parameters were used to .. document the physical and chemical properties of the overburden and underburden, to compare these properties to ground water quality, and to determine potential reclamation success." The data obtained from the geochemical analysis was compared to criteria derived from state and Federal agencies (USDA, BLM, Wyoming DEQ, and others). The criteria used for comparison and relative degrees of suitability are listed in Volume 2, Tab 6, Table 6-3, Page 6-19 of the permit application. The mixing of materials containing these elements during reclamation should dilute any adverse effects which would inhibit revegetation or degrade ground water. In four percent or less of the samples analyzed, pH acid/base potential, boron, manganese, cadmium and zinc exceeded suspect levels. Nitrate-nitrogen levels were excessive in fourteen percent of the overburden core samples taken at the Seneca II-W Mine. The locations of the holes which exhibited elevated levels were distant from one another. - 11 -