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RULE 2 PERMITS <br />Data collected for the springs and seeps were previously summarized in Table 2.04.7 -49. Two springs <br />(SPRLC -01 and SPRLC -02) maintained flow during July and August 2005 in Little Collom Gulch, and <br />produced a total of 0.30 cfs during spring runoff in June 2005, and 0.045 cfs during August 2005 <br />baseflow. Spring/seep SPRLC-03 only produced flow (0.009 cfs) in December 2004, and produced no <br />measurable flow for any other sampling event. Springs /seeps V 11 and V29 produced no measurable flow <br />for any sampling event. All Little Collom Gulch spring and seep flows subsequently infiltrated into the <br />valley fill or were captured by stock ponds, because no flow was observed at streamflow monitoring point <br />LLCG, which was dry throughout the 18 month sampling period. In the West Fork of Jubb Creek, the <br />three springs potentially affected by mining operations (VI, V 10, and V32) produced a total of <br />approximately 0.042 cfs in May 2006, and 0.024 cfs in September 2005. <br />Potential Impacts to Bedrock Groundwater Quantity <br />Drilling of exploration and monitoring wells by Colowyo and other parties in the Collom Lite pit area <br />identified very limited perched water in the shallow coal beds and interburden, and saturated conditions in <br />the lower third of the sequence to be mined (as discussed in Section 2.04.7). There are no continuous <br />non -coal aquifers in the saturated section of the pit to be mined. <br />No impacts are anticipated to the quantity of groundwater in the Williams Fork Formation or the Trout <br />Creek Sandstone of the Iles Formation. The Williams Fork Formation is not a significant water supply <br />source in the Danforth Hills. It is not used as a source of water where the valley -fill aquifers and surface <br />waters are accessible. The Trout Creek Sandstone aquifer is separated from the lowest coal seam to be <br />mined by approximately 400 feet in the Collom Lite pit area. Between this coal seam and the Trout Creek <br />Sandstone is a mudstone /shale, sandstone, siltstone, and coal sequence of the Williams Fork Formation. <br />About 200 feet above the Trout Creek Sandstone, a laterally continuous, smectite clay layer known as the <br />KM bed exists. This layer has very low to no permeability and, therefore, would be an additional <br />impediment to downward or upward groundwater flow. No impacts are anticipated to the quantity of <br />groundwater in the Williams Fork Formation or the Trout Creek Sandstone of the Iles Formation. <br />As stated previously, the land for the Collom Lite mining area and surrounding land is predominantly <br />owned and /or controlled by Rio Tinto Colowyo and /or its subsidiaries. There are numerous monitoring <br />wells on these lands which may be registered as wells (due to Colorado State Engineer's past rules and <br />regulations). No other private individual or group owns or controls any land in the Collom permit <br />expansion area. Thus, any well within the limits of the Collom permit expansion is owned and controlled <br />by Colowyo and the only impact from any dewatering will be on Colowyo itself. Table 2.04.7 -44 and <br />Map 11 C reflect the location and ownership and control status of these wells. <br />The closest known and registered /permitted non - Colowyo domestic or commercial wells are located <br />approximately two miles southeast of the initial Collom boxcut area. These wells are located in the <br />SW 1 /4, Section 7, T.3N., R.93 W. These wells are located below the base of the Williams Fork <br />formation, in the Iles Formation, or in valley fill material along Wilson Creek. This can be verified by <br />comparing the Geology map (Map 7A) with the well location map (Map 11 C). Therefore, these non - <br />Colowyo wells are located topographically, stratigraphically and structurally lower than the Collom Lite <br />pit location. Thus, no possible impact of these wells is possible from any dewatering of the Collom Lite <br />pit. <br />Maintailiing a dry pit, in the northern third of the proposed pit, may require dewatering in advance of <br />mining. This is based on the study performed by WMC (2005) on the hydrolotry of the Collom Project. <br />Based, an the field work and computer modeling performed by WMC (2005), dewatering wells may be <br />installed to dewater the rock strata below the Fab coal seam, with a projected depth at the Gc seam. <br />Based on their study, the wells will be placed on 1000 foot centers. This wall allcw for the cones of <br />Collom — Rule 2, Page 134 Revision Date: 9/28/11 <br />Revision No.: PR -03 <br />