2010-01-25_PERMIT FILE - C1981044A (3)

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"E" Coal Seam to Middle Sandstone The Middle Sandstone is the first recognized aquifer above the "E" coal seam. It ranged from 210 feet to 310 feet above the "E" coal seam. The Middle Sandstone is comprised of three (3) benches each extending over different portions of the mine property. The mined bench (topmost) covers the largest part of the property and is the unit monitored at EC. It is believed that all three benches, when present are hydrologically interconnected and behave as a unit. The monitored bench ranges from 50 feet thick in the south to 100 feet thick in the northeast part of the property, as shown on the Middle Sandstone Structure and Isopach Map (Map 12). "E" Coal Seam to the Twentvmile Sandstone The Twentymile Sandstone is a regionally recognized unit and outcrops prominently at EC. It is recognized as a significant aquifer. The Twentymile ranges from 495 feet to 610 feet above the "E" coal seam. Much of the early development of the No. 6 Mine will be south of the outcrop of the Twentymile and a large part of the first three (3) panels will be beneath the partially saturated Twentymile Sandstone. Refer to the Life-of-Mine Plan Map (Map 22) and the Subsidence Map (Map 30) for information regarding the position of [he Twentymile Sandstone relative to the mining areas. Site Specific Gealo The site specific geology of the permit area can be best addressed graphically. A series of large geologic cross- sections have been prepared utilizing geophysical logs. These-sections show graphically the relationships between the coal seams and enclosing strata. Particularly the major aquifers. Due to the sensitive technical information contained on the cross-sections it is essential that this information be kept CONFIDENTIAL. The following is a listing of the cross-sections and a brief description of their purpose: • Map 7A, Geologic Cross-Section A-A', this cross section depicts the geology from the "P" coal seam down to the Trout Creek Sandstone in a line running west to east through the central portion of the permit area. • Map 7B, Geologic Cross-Section B-B', this cross section depicts the geology from the Twentymile Sandstone down to the Trout Creek Sandstone in a line running North to South along the Western side of EC's Permit boundary. Map 7C, Geologic Cross-Section C-C', this cross section depicts the geology from the First White Sandstone down to the "C" coal seam in a line running North to South along the Western side of EC's Permit Boundary. EC has included site specific geologic data within an exhibit of the permit application. The following reports have been prepared as of the date of this application and are presented in the permit as Exhibit 8, Supplemental Geological Information: • REPRESENTATNE DRILL HOLE LOGS Geologist's interpretation of representative drill hole logs found within the permit area. Coal Seam Characteristics Presented in Table 9, Characteristics of Mineable Class Seams and Enclosing Rocks, is a summazy of the coal seam characteristics and geologic/engineering descriptions of the enclosing rocks. This table contains sensitive technical data and it is requested that the contents be kept CONFIDENTIAL. Permit Revision 04-34 2.04-9 Revised 7/2/04