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The overburden physical hydrological characteristics were derived from two U.S.G.S. wells, <br />DH-3B and DH-4 within the general area. Permeabilities at these two wells ranged from 0.37 <br />gpd/ft2 to 7.5 gpd/ft2. The two overburden wells (79-1 and 79-2) in the monitoring program <br />were chosen simply because water was observed in the overburden during drilling. A saline, <br />sodic, sodium bicarbonate water is derived from this aquifer, TDS ranges from 796 mg/1 to <br />1,708 mg/1, averaging 1,216 mg/1. Dissolved manganese concentrations exceed the domestic <br />standards regularly. <br />Upland terrace deposits are found sporadically throughout the permit area, where they have <br />not been eroded off. They can achieve thicknesses of up to seventy (70) feet thick within the <br />permit area. A perched aquifer in one of these deposits has produced a spring in Section 22, <br />T9N, R78W which has an average flow of less than 2 gpm. This spring is located outside the <br />area of proposed mine disturbance. <br />Alluvium is found in places along all of the draws draining the mine site, along the Canadian <br />River and along the Illinois River adjacent to the loadout. The alluvium within the draws is <br />predominately composed of clay with isolated sand and gravel lenses. Wells have been <br />strategically placed to intersect these lenses. To date, the calcium bicarbonate water quality <br />does not appear to have been altered by the mine. There are currently no wells along the <br />Canadian River alluvium east and northeast of the mine. <br />The alluvium along the Illinois River near the loadout is less than 25 ft. thick. Underflow is <br />estimated at 1.5 acre feet per day on material whose permeability is estimated to be 2500 <br />gpd/ftz. The water quality was initially characterized as a calcium bicarbonate water with <br />small concentrations of iron, magnesium sulfate and nitrates. <br />Surface Water <br />The general area which includes the mine plan area is drained by the Canadian River, a <br />perennial stream that flows northward into the North Platte River at Northgate, Colorado. <br />The Canadian River drains 114 square miles between USGS Stations 06619400, upstream of <br />mining activities, and 06619450 downstream of mining activities. The drainage area between <br />these two monitoring stations includes the Marr Mine plan area, other abandoned and <br />reclaimed mines, and various agricultural enterprises. The agricultural usages of land <br />surrounding the mine plan area are primarily non-irrigated rangeland. Lands immediately <br />paralleling and of varying widths along the Canadian River have been classified meadowland. <br />A portion of the meadowland is cut for hay. This land is not shown precisely as various <br />acreages in each category. Along the Draws downstream from the permit area, there are no <br />indications that this area is used for anything but rangeland. The Canadian River has a <br />recorded average base flow rate of four (4) cfs. The recorded water flow rate has reached two <br />hundred (200) cfs during the snow melt-rainfall period. Most of the water received in this <br />Marr Strip Mine, C-80-006 16 December 9, 1992 <br />