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n <br />• Formation." These formations consist of interbedded sandstone, shale, siltstone, and <br />coal units. <br />The spoil derived from the surface mine will be from the Raton Formation. <br />The sequence removed is estimated to be composed of 75 to 90 percent shale and <br />10 to 25 percent sandstone. The average dip of the coal seams in the surface mine <br />area is 1.5 to 1.7 degrees to the southeast, towards the axis of a syncline located <br />roughly through Lorencito Canyon. <br />Seeps have been mapped on the site primarily near major drainages. The <br />coal seams are considered likely aquifers to develop seeps. No seeps were mapped <br />in the proposed disposal areas. Pre-construction site specific observations will be <br />required to confirm conditions at each site. <br />Large landslides or block movements were not identified in the geological <br />assessment. Localized failures may be present and can be identified in pre- <br />• construction site specific investigations. <br />The drainages in the disposal areas are considered ephemeral. Shallow <br />ground water may occur seasonally. The small drainage areas and post-construction <br />surface drainage controls will mitigate the potential effects to a significant degree. <br />Soil Conditions <br />The disposal sites are located in mild to very steeply sloping areas. The <br />geologic report indicates alluvial/colluvial soils in borings to depths of 10 to 22 feet. <br />The deeper alluvial soil depths are associated with the larger drainages, in areas not <br />planned for spoil disposal. Soil mapping indicates predominantly clay, clay loam and <br />silty clay loam colluvium-residuum in the steeper portions of the site to depths on <br />the order of 1 to 3 feet. Deeper clay soils were found in milder sloping areas, such <br />as in the area of Fills 12, 14 and 17 (Fig. 1). This is consistent with our experience <br />• in the area. <br />LORENCITO COAL COMPANY <br />CTL/T Y5,351 5 <br />