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99 <br />8 CONSIDERATIONS FOR FEASIBILITY AND PERMI <br />The information in this report was developed in support of the Collom Project Pre - <br />feasibility Study. The key aspects of the site hydrogeology related to mine dewatering <br />and slope depressurization were investigated with a relatively high level of detail at the <br />pre - feasibility level. However, some additional evaluations are recommended if a <br />decision is made to carry the project to the detailed feasibility level. This section <br />provides a discussion of the feasibility -level considerations related to mine hydrology. <br />During the pre - feasibility study, a number of investigations were made, and monitoring <br />activities initiated, that will be used for developing the site permitting documents. These <br />include the initiation of baseline monitoring of surface water, springs and seeps and <br />groundwater, and the preliminary development of a regional groundwater flow model, <br />which will be submitted as a separate report. Additional data and evaluations that are <br />C recommended for project permitting, including ongoing hydrologic monitoring, <br />geochemical evaluations and evaluation of potential hydrologic consequences of mining, <br />are discussed in this section. <br />8.1 Feasibility considerations <br />The pre - feasibility study indicates that mine dewatering and slope depressurization <br />measures will be needed to develop the Collom Mine. The pre - feasibility level <br />investigations included installation of a number of piezometers, water level <br />measurements across the site, single -hole hydraulic testing, and a long -term pilot <br />dewatering well test in the Phase 1 box cut. At a feasibility level, additional information <br />should be obtained to reduce uncertainty and refine the dewatering /depressurization <br />system design. Recommended feasibility -level evaluations are described below. <br />8.1.1 Definition of the hydrology of the burn zones <br />The 2004 exploration program defined areas of extensive burn within the Collom study <br />area. These areas occur mainly along the exposed sides of the major stream valleys <br />that are deeply incised into the coal- bearing formation. The burn zones are likely to <br />have significantly different hydrogeological characteristics than other areas as a result of <br />the burning and collapse that has occurred. If the burn zones are primarily drained, then <br />they will have minimal impact on dewatering. However, if the burn zones extend below <br />the water table, then such zones, when they are intercepted by the pit, may result in <br />• <br />2572 -R2 <br />Colowyo Coal Company <br />Water Management Consultants <br />