2010-12-17_REVISION - C1981019 (127)

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3 r 0 Two unnamed sandstone units have also been identified that may produce water where they are saturated. These are located above the F ab coal sequence and below the G coal sequence. It is not known at this time how continuous these units are or what their respective potentiometric surface elevations might be. The F and G coal seams, the Trout Creek sandstone and the two unnamed sandstone units mentioned above have been identified as the most likely units that will produce water during mining. Therefore, these units are identified as potential monitoring targets in this work plan. Saturated alluvium also occurs in each of the main drainages including Straight Gulch, Collom Gulch, Little Collom Gulch, and Jubb Creek. The alluvium of each of these drainages is also considered a monitoring target. 1.1.5 Surface water The proposed operation is located within the watershed of the Yampa River. Individual watersheds within the project area include Straight Gulch, Collom Gulch, Little Collom Gulch and Jubb Creek. Jubb Creek joins Wilson Creek before it flows into the Yampa. The remaining drainages flow into Morgan Gulch before it joins the Yampa. Two stream gauging stations were maintained by the USGS in the past on Jubb Creek C and Morgan Gulch. The period of record for these two stations is: 1975 to 1981 and 1980 to 1981, respectively. In general the surface water courses are narrow channels deeply incised into the broader flood plain. The channels are typically a few feet across in width and incised about 5 to 10 ft. 1.2 Project description Kennecott Energy Company (KEC) is considering the development of the Collom mining pit located approximately four miles west of the current Colowyo mining operation. The current operation is located in Northwest Colorado midway between the cities of Craig and Meeker on Highway 13 at mile marker 64. The mine plan for the proposed Collom pit is still being developed and the following presents the most current development scenario. Mining will likely occur in four phases the first two of which are indicated on Plan 1. Mining would then proceed to the NW and SE "wings" in later phases. An initial box cut will likely be made at the down -dip or northern extent of mining. Mining is expected to proceed up dip using either a combination of truck shovel and dragline or just truck shovel. Material from the initial box cuts will be placed as valley fill in Little Collom Gulch. The exact footprint of this valley fill has not been determined. 2572 -R1 Colowyo Coal Company, L.P. Water Management Consultants