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• 3.0 South Oak Creek <br />Part of the proposed underground workings will pass under <br />South Oak Creek. This stream is ephemeral and has some summer <br />flow along a stretch of about 200 feet from a spring (TP-S2 in <br />drawing of General Mine Area) controlled by joints rather than <br />from base flow in the patchy and thin alluvial fill. The flow <br />starts and ends within a portion of the creek that coincides with <br />the trend of a prominent joint trace. It is possible that the <br />joint extends down to a perched aquifer very near the surface. <br />The flow disappears into the joint system again and is suspected <br />to reappear along the lower portions of the unnamed tributary of <br />South Oak Creek (TP-S3 in drawing of General Mine Area). There <br />are no water well users along this creek within the project area. <br />The alluvial fill along South Oak Creek ie not continuous <br />and individual patches are under 10 acres in area. The boundary <br />of the unconsolidated deposits coincides with that of the boulder <br />• conglomerate shown on the Surface Geology and Top of Brookside <br />Coal drawing. <br />At Section E (fig. 2.06.8-5) the valley bottom is covered <br />with sand and gravel. The north side of the bank rises <br />vertically for 6 feet from the channel bottom. In this section, <br />2 feet of clay soil is underlain by very poorly sorted boulder <br />conglomerate. About 50 feet downstream from Section E sandstone <br />bedrock outcrops along the channel bottom expose the contact with <br />the overlying unconsolidated deports. Still further downstream, <br />an 11-foot high bank on the west side shows 3 feet of clay Boil <br />at the [op followed by B feet of boulder conglomerate showing <br />coarse bedding where lenses of coarse sand and gravel occur. The <br />sequence rests on exposed bedrock. The boulder conglomerate <br />deposit is thickest near the edges of the active channel of South <br />Oak Creek, particularly the west aide, but quickly wedges out <br />away from the channel banks and is replaced by either thin <br />alluvium or colluvium material. At Section F (fig. 2.06.8-6) the <br />alluvial fill on the west side of Oak Creek has been disturbed, <br />JFSA-77 <br />