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.~^' <br />• <br />C.O.M., Inc. atone time mnaidered raising the <br />however as an alternate to that, C.O.M., I <br />materials from the tai ' un e~a ~are~' _ <br />-® ,~/o <br />P"^`~2 <br />e <br />lc.~a-r <br />.. s impoundment area, <br />:ehds to remove 90MC of the <br />• ar sin a ilin e tailings im~ <br />area wi no us for disposal purposes but only for a holding facility for <br />materials that will be shipped to our brick making facility. <br />~~ <br />o%Q.. ~ a <br />IS _/ <br />• The area northeast of the milleits was selected for the construction of the im- <br />poundmentdam to contain the tailings that are produced by the milling pro =~~ <br />teas 1 see Map A). The site selected for the ~ ' <br />properttzo~toied by nc An adequate storage capacity was developed <br />on`uhis site for a mim- 'mum o f years of milling operations at the anticipated <br />rate of milling activity. The topography of this site is suitable for the conatruc- <br />• tion and maintenance of a hillside tailings pond, with gentle open slopes. The <br />subsurface conditions were ideal for constructing a stable embankment and <br />safely containing the tailings that were produced. The entire area is one of low <br />seismic activity, and there is little risk to the tailings pond embankment from <br />earthquake activity in this location. The terrain above the proposed tailings <br />• pond that could provide a precipitation catchment area is limited, and there are <br />no streams above or directly below this site. <br />site ie situated on 2.125 acres of <br />portion of intervening land is <br />• claim. <br />A <br />Topographically, the tailings impoundment area can be characterized as gently <br />eloping terrain. The present slope gradient of the ground that was selected <br />varies from 16 percent on the northeastern edge of the site to 14 percent on <br />~ the southwestern edge. The absence of even an intermittent stream channel <br />through this area makes this Bite a suitable one for the construction of a hill- <br />side tailings dam <br />A very important factor in the selection of this location for tailings retention <br />was the hydrological investigation, which focused on the precipitation, ground <br />• water, and potential water runoff inflow. Based upon historical stream flow <br />records, the U.S. Geological Stuvey has calculated that 42 percent of the <br />annual precipitation in Boulder County~a mountain region Howe to the plains <br />each year. Because of the limited storage capacity of the mountain region's <br />crystalline rocks, a further 55 percent of the annual precipitation is returned to <br />• the atmosphere by evapotranspiration. Due to the impermeability of these <br />rocks, snow melt and rainfall infiltration account for only 3 percent of the <br />yearly precipitation. According to the U.S. Weather Bureau, the mean annual <br />precipitation that occurs at this altitude is 20 inches per year. An evaluation <br />of the catchment area above the proposed tailings pond determined that a <br />total of 1.267 acres of ground surface is immediately adjacent to the embank- <br />~ ment site. Based upon these parameters, the catchment area receives an <br />average of 2.12 acre feet of precipitation annually. Tide amount of precipa- <br /> <br />