2010-05-07_PERMIT FILE - C2009087 (6)

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The thicknesses of those portions of the Mesaverde Group and the Lewis Shale residing above the Wadge Seam in the mineable portion of the PSCM permit area are shown on Map 2.04.6 -M3, • Overburden Isopach (confidential). The overburden thickness ranges from outcrops on the east of the PSCM permit area to 1,750 feet thick. Stratigranhy and Physical Characteristics of Coal Seams in the Area to be Mined The Holderness Member, the Twentymile Sandstone, and the thick marine shale member make up the majority of the Williams Fork Formation. The lower portion of the Williams Fork Formation consists of the coal - bearing sequence. This sequence, the Middle Coal Group of the Mesa Verde Group contains the Lennox Seam, Wadge Seam, and the Wolf Creek Seams. The lowest coal, Wolf Creek, is locally mapped as two seams, the WF upper coal seam and WC lower coal seam. Irregular seam thickness and lateral continuity have limited reining of the Wolf Creek. Near the base of the WC coal seam is a volcanic ash fall tuff called the Yampa Bed, which is used throughout the Yampa Coal Field as an important correlation marker bed. The Lennox Seam is located 10 to 15 feet below the marine shale member, and ranges in thickness from zero to five feet. The low seam height, poor quality, and poor lateral continuity of the Lennox Seam render it unsuitable for underground extraction methods. In the proposed PSCM underground mine area, the strata below the Lennox Seam consists mainly of stacked deltaic shore face sequences. Four distinct sequences have been mapped through the PSCM area. The "B" and "C" sandstones are the dominant members locally. They are characterized by a coarsening of mean grain size upwards within each sequence. The lithologies consist of mudstones and claystones, • siltstones, and very fine - grained interbedded sandstones. The combined thickness of these sequences range from fifty to sixty feet. These rocks directly overlie the Wadge Seam, which is the target of the planned PSCM underground operations. The access to the Wadge Seam via the portal opening will be constructed in the aforementioned geologic units west of the reclaimed Seneca II Mine highwall. Map 2.04.6 -M2, Boreholes and Stratigraphic Cross Sections, presents the location of geologic cross - sections depicting the stratigraphy in the area to be mined. The cross sections are presented in Exhibit 2.04.6 -E1, Geologic Information — Geologic Cross Sections (confidential). The Wadge Seam ranges in thickness from eight to 11.5 feet throughout most of the area to be mined. Map 2.04.6 -M4, Wadge Coal Seam Thickness Isopach (confidential), presents an isopach of the Wadge Seam. High heating values and volatile content place the Wadge Seam in a High Volatile, Group Bituminous Coal classification. The lower one foot of the Wadge Seam is comprised of a high ash "bony coal" which is relatively uniform across the mine property. This unit commonly forms a gradational contact with the underlying carbonaceous mudstone. No significant amounts of acid - forming, toxic - forming, or alkalinity - producing materials have been identified within the Wadge Seam. Lateral continuity and consistency of the Wadge seam is good to excellent. Sample locations are illustrated on Map 2.04.6 -M2, Boreholes and Stratigraphic Cross Sections, and select lithologic logs of these drill holes are included in Exhibit 2.04.6 -E2, Geologic Information — Lithologic and Geophysical Logs (confidential). Lithologic characteristics, physical properties, and chemical analyses of the stratum immediately above (0 -10') and immediately below (0 -5') the coal seam were collected. Samples were analyzed • for all soluble salts and toxic elements listed in the "Guidelines for the Collection of Baseline Water Quality and Overburden Geochemistry Data" (CMLRD, 1982). A detailed summary of the over- PSCM Permit App. 2.04 -27 6/15/09