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i <br /> ' smelter, this concentrating mill is situated as close as is <br /> practicable to the source of its ore supply. The proposed <br /> gravity and flotation concentration mill was constructed <br /> ' approximately one half mile east of Gold Hill. Water for the <br /> mill will be drawn from Left Hand Creek, and pumped up a <br /> pipeline in Aikens (Lick Skillet) Gulch to the millsite by <br /> means of two pumping stations, where it will be stored in <br /> underground mine workings. Three phase power for the milling <br /> facility is obtained from the Public Service Company of <br /> Colorado, which has extended this power another 640 feet <br /> along an existing line, and install 3 transformers near the <br /> southwest corner of the mill building. <br /> ' While there were many obvious advantages to building the mill <br /> in this location, there were also several apparent <br /> disadvantages to bifurcating the mining and milling <br /> operations. Property acquisition costs for a millsite <br /> located on the plains would be higher than the costs for the <br /> entire milling facility on Horsfal Flat. Furthermore, a mill <br /> constructed on the plains would require all of the same <br /> necessities (such as water, power, and a suitable tailings <br /> disposal area) as one built in the mountains. Aside from the <br /> extra costs of transporting are an additional 10 to 25 miles <br /> to a milling facility on the plains, the concentration of <br /> these ores near their source would greatly curtail the number <br /> of ore trucks using Boulder County roads, and obviate their <br /> ' traveling through Boulder. Actual construction costs were <br /> estimated to be about the same for the Horsfal Flat location <br /> as at any of the other locations that were evaluated. <br /> ' The gently sloping topography of the Horsfal Flat site <br /> reduces operating costs by accommodating the construction of <br /> a hillside plant with a straight-line flow sheet that <br /> ' eliminates the costly elevation of are and material . <br /> Geologically, the millsite foundation is supported by stable <br /> Boulder Creek granite. A review of the historical records, <br /> ' and a field examination of the area did not disclose any <br /> underground mine workings that extended beneath the milling <br /> complex. The nearby Oscar mine shaft was a shallow, caved <br /> discovery shaft, without any lateral workings; and the Wynona <br /> mine workings are inclined towards the northwest, away from <br /> the millsite. <br /> ' Perhaps the major reason for the final selection of the <br /> Horsfal Flat site was its suitability for the safe, efficient <br /> and environmentally acceptable disposition of the tailings <br /> that result from the milling process. Other mountain sites <br /> ' that were examined did not afford the opportunity to <br /> construct a hillside tailings structure, with a limited <br /> upstream drainage area. Finally, constructing a tailings <br /> ' embankment northeast of the proposed mill building has less <br /> visual effect on the landscape than any of the other possible <br /> mountain sites. <br /> 1 <br />