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• t'MLRH -Exhibit G <br />Water Information <br />Page 6 <br />the Dowe Flats syncline. Tn similar geologic environments, tight folding such as this tan reailt in <br />fracduing along the fold axes. <br />North of the proposed site, the Dowe Flats syncline is tttrrtcated by a fault that crosses the southern <br />pacts of Sections 3 and 4, T3N, R70W. This fault is an easterly dipping thrust fault extending across <br />the north end of Rabbit Mountain (Masters, 195'x. A review of law altitude aerial pho0ography <br />revealed alignments which appear to support the presence of a fault across this area. <br />A summary of general water-bearing properties for the fon~nations that outcrop in the proposed mine <br />area is presented below followed by a derailed discussion of the Pierre Shale, Niobrara Fomlation and <br />the unconsolidated valley fill. <br />Generalized geologic section for the site area and a description of the local aquifers are included as <br />Figures G~ and G-5 respectively. A summary of typical well yields for each unit is shown on these <br />sections. The rock units in Dove Flats were mapped by Southwes6em Portland Cement Company <br />• in greater detail in 1985 and 1986. The formations and their thicknesses in Dowe Flats are presented <br />in Table G-7. The thiclmess information was derived from outcrops, drill Dore, and cuttings. <br />Unconsolidated Valley Fill -The unconsolidated valley ffi deposits are composed of alluvium, <br />colluvium deposited in large part by sheet wash as well as by the ephemeral streams in Dowe Flats, <br />and windblown material. These deposits range from about 12 m 30 fief brick where measured in <br />boring and are poorly-sorted, cnrdely-bedded strata The formation is thickest along the stnam cbartnels <br />and in the southern part of Dowe Flats near the St. Vrain Creek floodplain. The valley fill becomes <br />progressively thinner to the east and west along the steeper flanks of Dowe Flats. <br />Included in this formation is the weathered zone of bedrock found just below the valley fill. The well <br />yields in the valley fill aquifer are reported by the Colorado Geological Survey (CGS) as being small <br />to inadequate (less than 15 gallons per minute). <br />>~plam~D posits -South of the mine property, St. Vrain Cn3ek flows in a valley wt into <br />Quaternary-age deposits of unconsolidated alluvium. These deposits are thicker than the valley fill <br />deposits associated with the proposed mine area at Dowe Flats and are composed of stream deposited <br />boulders, gravel, sand and some silt and clay. This type of deposit oo:urs in present and ances~al <br />• stream valleys, in terraces along present stream valleys and on the slopes of the foothills. Tn general, <br />