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MINING PLAN • • EXHIBIT D (coot) <br />GEOLOGICSETTING <br />The affected lands are located on an isolated terrace deposit of gravel that is part of the <br />Beldon formation of Pennsylvanian age which outcrops along the Colorado River in this area. These <br />outcrops occur from Bums to the confluence of the Eagle River and Colorado River. In the <br />immediate area of the river, the terrace gravels are superimposed upon the Beldon formation a gray <br />to black shale mixed with sandstone. These aze unconsolidated deposits of Holocene aged materials <br />that accumulated when the river was much lazger than it is now. All or a major part of the gravel is <br />probably of alluvial deposited origin. Overlying the terrace gravel is a thin layer of soil. See Exhibit <br />UJ for the site specific soils information. The gravel, and to a lesser extent the soil, are permeable <br />and permit extensive surface water infiltration. According to the landowner, it has been difficult at <br />times to transfer irrigation water to the east edge of the property due to the high infiltration. <br />Gravel depth in the terrace could go as deep as 120 feet depending on the nature of the gravel <br />deposit. We have not been able to find out the exact depth ofthe deposit because of the large cobble <br />contained in the deposit. We think the gravel depths on the site range from 120 to 230 feet or more <br />in thickness. Site information suggests that the topsoil/growth medium is between 2 and 26 inches <br />across the site, averaging 14 to 18 inches overall. <br />The operator plans Yo mine the upper portion of this deposit leaving a bench similar to what <br />now exists, only lower in elevation. The grading plan shown on Map Exhibit F shows how the area <br />will look afrer taking the top 40 feet of gravel off the site. Eagle County requires excavations to be <br />confined to the azea 10 feet above the river; the operation will be between 80 feet and 100 feet above <br />this level. The floor of the mined area will be above the level of the alluvial water flow associated <br />with the Deep Creek and the Colorado River. <br />12 <br />