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Texture Analvsis <br />• Texmre analysis of the overburden and inner burden indicates that the predominant composition <br />is sand. Clay is the next most prevalent constituent. Overall, the texture of the overburden and <br />inner burden will not present any problems with respect to the backfilling operations. The <br />results of texture analysis are presented on Table 5, OverburdenlInterburden Textural Analysis. <br />Physical Properties <br />The physicai nature of the overburden and inner burden is described in reports prepared by <br />CTL/Thompson, Inc. As described in those reports, the overburden consists of topsoil, gravel <br />and clayey materials overlying bedrock. The inner burden consists of sandstone, siltstones and <br />shales. The shales will have a relatively high erodability and compaction factor. The sandstones <br />and clay, however, are hard to moderately compacted immediately below the C Seam and very <br />hard to well cemented beneath the A and B Seams. Therefore, the compaction and erodability <br />factors of these materials will be relatively low. A 25 percent swell has been computed for these <br />materials based upon compaction and density figures. <br />2.04.7 Hydrologv Information <br />Groundwater <br />In an endeavor to define both the quantity and quality of groundwater within the permit area, <br />adjacent area, and general area, the Chimney Rock Mine commenced hydrologic investigations <br />early in the permit application formulation process. Such investigations included the review of <br />topographical maps, aerial photography and existing geologic data as described in 2.04.6, <br />Geology Description. Baseline investigations commenced in October 1980 which further defined <br />the hydrologic regime of groundwater within the area. <br />The baseline groundwater quality program as well as the quarterly analysis conducted includes <br />analyses of the following: Field data (pH, alkalinity, conductivity and temperature), trace <br />metals, physical parameters and chemical parameters. The monitoring program includes the use <br />of sampling stations. Map 4, Regional Hydrology, provides the location of each of the stations. <br />This map defines the permit area and adjacent area and depicts numerous wells which were <br />included in the baseline groundwater sampling program conducted in October 1980. The wells <br />were utilized as groundwater monitoring points during monttily and quarterly sampling periods. <br />Updated results of groundwater monitoring are provided to the Division in the Annual <br />Hydrology Report submittals. Locations and frequency of monitoring are provided on Map <br />4, Regional Hydrology, and Table SA, Hydrologic Monitoring, respectively. <br />For the purposes of this dissertation, groundwater will be discussed as occurring in three <br />systems--a limited aquifer associated with the coal; an alluvial aquifer, which is hydrologically <br />related to the coal; and an impermeable zone formed by the Picture Cliff sandstone. As <br />described in 2.04.6, this formation is composed of massive sandstone which ranges up to 250 <br />feet in thickness. Groundwater occurrence below the point of contact between the Fruitland <br />• 2.04-13 Revised 12-O1-91 <br />