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16 <br />J' <br />J <br /> <br />I~ <br />L <br />I <br />formation are summarized in Table 1. <br />The permeabilities listed in Table 1 are intrinsic permeabilities ex- <br />pressed in milli-darcys. The relationship between hydraulic conductivity, <br />K, (also often called permeability) in centimeters per second an~i intrinisic <br />permeability, k, in milli-darcys is K = 8.952 x 10-~ k for water at 63° F. <br />The magnitudes of permeability and porosity listed in Table 1 are of less <br />importance to the present discussion than is the variation. There is no <br />apparent trend in pe rnreability with respect to location of the wells. In <br />other words, there is no evidence in these data that the permeability of <br />the overburden sandstones at the Maxwell is significantly different from <br />that at the Allen. Furthermore, the permeabilities of the sandstones of <br />• <br />J <br />the Raton formation fall within a surprisingly narrow range of 0.12-1.65 <br />milli-dotty, with the large majority of values clustered around the mean. <br />This observation lends additional credence to the conclusion that the <br />channel sandstones 1n the Raton formation in the vicinity of the Allen and <br />Ma~(we11 Mines are quite uniform with respect to Dermeability. even thnuah <br />their occurrence, geometry and lateral continuity are very heterogeneous. <br />~.~--- - - <br />As indicated Dreviousiv. the location and geometry of the Purgatoire <br />River does not appear to be related to the occurrence of fractures, joint- <br />ing, or faulting. Therefore, the probability of occurrence of fractures <br />connecting the Maxwell coal seam with the river and associated alluvium <br />is~no greater at the Maxwell Mine than at the Allen Mine. This, coupled <br />with the conclusion that. the vertical perm>eabilities of the most permeable <br />overburden strata are not significantly different at the two mines, leads <br />to the expectation that downward flaw from the valley induced by mining <br />beneath the valley at the Maxwell will not be significantly different from <br />that experienced at the Allen. Mhile the contribution of downward flow _.,~ rrj <br />from_the valley to th~total inflow at the All n annot be determined mine ~~' <br />personnel did not observe any noticeable increase in mine inflow as several <br />~- <br />headings were driven beneath the valley at various times during the life of <br />the mine. Using the penneabilities listed in Table 1, estimates_of the <br />poEential magnitude of vertical inflow from the valley are made subsequently <br />- -- -'-- <br />in this report. <br />The above discussion has significance only with respect to the <br />