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8 Geologic setting <br />Danforth Hills Coalfield is believed to be such a fault structure. The latest movement <br />along the fault was during the Laramide Uplift, a Tertiary orogenic event which led to the <br />uplift of the modern Rocky Mountains. This episode of uplift was a compressional event <br />that eventually formed faults and major folds such as the Axial Basin Anticline north of <br />Colowyo's property holdings (Figure 2.2). The axis of the Axial Basin Anticline occurs in <br />the broad valley just north of the Colowyo study area. <br />Numerous large -scale anticlines, domes, and synclines formed in the region as a result <br />of this last compressive event. Superimposed on these larger -scale folds are smaller <br />secondary or accommodating folds, although some workers suggest a different episode <br />of deformation formed them. This combination of structural features led to the present <br />geometry at the Collom study area. <br />2.2 Project area stratigraphical framework <br />To develop a better understanding of the project area stratigraphy for the combined <br />purpose of coal resource delineation and hydrogeologic characterization, an extensive <br />drilling program was undertaken by KEC. Technical support during the program was <br />provided by the Collom Geological Team, Call and Nicholas (CNI) (oversight of detailed <br />core logging and selection of samples for geotechnical analysis) and WMC (oversight of <br />well and piezometer installations). The drilling program and the site stratigraphy are <br />described below. <br />2.2.1 Geologic exploration program <br />Numerous borings were drilled in the Collom study area in 2004 and 2005. Borings <br />were advanced, if possible, to the KM (a volcanic marker bed described in <br />Section 2.2.2), or to the Trout Creek Sandstone. Cuttings from these borings were <br />examined and described for lithologic characteristics in 5 -ft increments. These borings <br />were then logged using a minimum of gamma, caliper, density, and resistivity <br />geophysical methods. <br />Borings were also drilled to collect continuous and spot core samples to characterize <br />rock and coal characteristics. Core samples were examined for lithology and structure, <br />fractures and other parting, hardness, and rock quality designation (RQD). Rock and <br />coal core was submitted for geomechanical testing. Coal core was also submitted for <br />quality analyses. <br />All data collected from the field drilling program was entered into a computer database. <br />These data were combined with previous drill hole data to improve the understanding of <br />the coal structure in the Collom study area. <br />2.2.2 Local stratigraphy <br />The following description of the local stratigraphy is focused on the hydrogeologic <br />aspects of the site lithology. The hydrogeologic characterization included an evaluation <br />of current and future groundwater conditions, surface water flow, water quality and slope <br />dewatering /depressurization. The following summary of site stratigraphy includes an <br />evaluation of the coal beds, and interburden with characteristics affecting <br />dewatering /depressurization. <br />2572 -R2 Colowyo Coal Company <br />Water Management Consultants <br />