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i <br /> 16 <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 and intrinisic <br /> permeability, k, in milli-darcys is K = 8.952 x 10-7 k for water at 63' F. <br /> 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 permeability 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 /> the Raton formation fall within a surprisingly narrow range of 0.12-1 .65 <br /> milli-darcy, with the large majority of values clustered around the mean. <br /> This observation lends additional credence to the conclusion that the <br /> channel sandstones in the Raton formation in the vicinity of the Allen and <br /> Maxwell Mines are quite uniform with respect to permeability, even though <br /> their occurrence, geometry, and lateral continuity are very heterogeneous. <br /> As indicated previously, 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 /> isino greater at the Maxwell Mine than at the Allen Mine. This, coupled <br /> with the conclusion that the vertical permeabilities of the most permeable <br /> overburden strata are not significantly different at the two mines, leads <br /> to the expectation that downward flow 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. While the contribution of downward flow <br /> from the valley to the total inflow at the Allen cannot be determined, mine <br /> �i <br /> I personnel did not observe any noticeable increase in mine inflow as several <br /> headings were driven beneath the valley at various times during the life of <br /> the mine. Using the permeabilities listed in Table 1 , estimates of the <br /> potential magnitude of vertical inflow from the valley are made subsequently <br /> 1 in this report. <br /> ] The above discussion has significance only with respect to the <br />