2009-05-12_GENERAL DOCUMENTS - C1981025

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These seams outcrop within the permit area (bedrock, covered by colluvial or alluvial materials). The A seam is a seven- to ten-foot-thick coal that lies above the Rollins Sandstone of the Iles Formation. The B-seam, three to five feet thick, lies forty to sixty feet above the A seam. The Anderson seam is approximately nine to ten feet thick and lies approximately eight-hundred feet above the A seam. Ground Water Hydrology There are three major bedrock aquifers within the mine area: the Upper Sandstone, the Middle Sandstone, and the Rollins Sandstone. These are regional aquifers and are relatively thick and laterally extensive throughout the mine area. The Rollins Sandstone is below the lowest coal seam that was mined (A seam) and is within the Iles Formation. The A coal seam, the Middle Sandstone and the Upper Sandstone all lie within the Bowie member of the Williams Fork Formation. The Anderson coal seam lies within the Paonia member. The North Thompson Creek No. 1 Mine is in the A seam, while the No. 3 Mine is in the Anderson seam. There was some development work in the B seam at the No. 1 Mine. In addition to the sandstone aquifers mentioned above, several other potential sandstone aquifers exist above and below the Anderson seam. However, these sandstones are thin and laterally discontinuous. A shallow and discontinuous alluvial aquifer exists on portions of the permit area adjacent to North Thompson Creek. The loadout site, located adjacent to the Roaring Fork River, is situated on an ancient valley floodplain. The alluvium adjacent to the river at this point is laterally extensive with thicknesses from 40 to 50 feet. Surface Water Hydrolo9y Two perennial streams are in the mine site permit area: North Thompson Creek and Middle Thompson Creek. The watersheds of both drainages are very similar. Elevation ranges from 7,600 feet at the area of the former mine office to over 11,000 feet in the headwater. Stream flow on North Thompson and Middle Thompson Creeks is derived primarily from snowmelt. Flows resulting from snowmelt typically have a gradual rise, moderate peak, lengthy recession and large volume. The peak occurs in May or June, while base flow is in late fall or winter. All surface disturbances at the mine site are in the North Thompson Creek drainage, except for small areas associated with a ventilation adit, a ventilation shaft, and two water monitoring flumes located in the Middle Thompson Creek drainage. Underground workings of the No. 1 Mine extend from entrance portals in the North Thompson Creek drainage south into the Middle Thompson Creek drainage. The underground workings for the No. 3 Mine are entirely within the North Thompson Creek drainage. All surface disturbances at the loadout site are in the Roaring Fork River drainage basin. North Thompson Creek C-1981-025 Permit Renewal 05 12 May 2009 6