Laserfiche WebLink
- 16 - <br />The predominant bedrock encountered in the NX core holes was a <br />silty to very silty claystone. The claystone was carbonaceous to very • <br />carbonaceous near the coal beds and gray to black in Dolor. Near the <br />surface of the site in Test Holes 9, 11, 14, 15 and 16, we encountered <br />an interbedded fine rained, light to medium gray sandstone-claystone <br />material. This sandstone-claystone was interbedded with the claystone <br />described above and layers of sell-cemented, thicJc bedded sandstone. <br />The interbedded sandstone-claystone is also generally present beneath <br />the lower coal seam. <br />A section of the site across the valley is shown on Fig. 5. The <br />position of this section is shown on Fig. 3. Zfie section presents our <br />interpretation of the subsurface conditions beneath the silos in the <br />vicinity of Test Holes 16 and 1° and northeast across the valley <br />perpendicular to the approximate strike of the bedding in the area. . <br />This section indicates that the formation underlying the site dips <br />approximately 7° towards the rortheast at this location. The upper <br />croal seam encountered in our test borings apparently daylights at or <br />slightly below the existing elevation of the valley bottom. We <br />believe the coal seam has been reiroved from the valley bottan by <br />erosion. The deeper opal seam appears to extend well below the <br />valley. <br />Dam Site: The natural soils encountered in test borings S-6 <br />through S-8 in the vicinity of the sediment pond embankment are sand <br />and silt mixtures comparable to the materials encountered further up <br />the valley beneath the building sites. However, the depth of <br />overburden soil at the sediment pond embankment appears to vary <br /> <br />