PERMFILE66600

• Permit No: C1981010
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: Utility Wastes
• Section_Exhibit Name: Appendix N
• Media Type: D
• Archive: No

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5.0 DISCUSSION OF RESULTS
In the southern area of the mine ([dell Site GZ), water
],evels decrease with increasing depth. Although ground-water
movement is primarily along bedding planes, this water level
relationship indicates that some downward, cross-bedding flora
is present.
Water moving within the Twenty rlile Sandstone Loses
much less pressure head than water moving the same distance
within the less-permeable Upper [•Iilliams Fork Formation. Con-
sequently, as ground water moves northward and docan-dip, the
pressure relationship between the Twenty Mile Sandstone and
the Upper Williams Fork is reversed. In the more northern parts
of the mine, water levels still decrease caith increasing depth
within the shallower sections of the Upper [Williams Fork. Hoca-
• ever, the Twenty ifile Sandstone becomes a relatively high pres-
sure artesian aquifer. Ground water still moves primarily along
bedding planes. North of the point of reversal of the pressure
relationship, some upward, cross-bedding flow takes place within
the Twenty Mile Sandstone and the lowermost section of the Upper
Williams Fork. Figure 5-1 displays a generalized vieca of the
probable configuration of equipotential lines and flow directions
along a dip (north-south) section of the Trapper Mine.
In the Big Bottom area, near the Yampa River, the
ground-water level relationships are similar to the relation-
ships in the northern mine area. That is, water levels decrease
with increasing depth in the shallower strata, and then increase
to relatively high pressure conditions in deeper strata. Al-
though the cause of high pressures within the deeper strata is
unknocan, the Twenty Mile Sandstone or sandstone beds of the
Upper Willimas Fork are likely sources of relatively high pres-
s • sures.
5-1