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No. 5 Mine Inflow Report <br />1.1 Introduction <br />Permit No. C-044-81 issued October 19, 1983 requires Cyprus Empire <br />Corporation (Empire) to conduct an annual mine inflow study. The <br />following is submitted to satisfy this requirement. <br />1.2 Geologic Setting <br />The No. 5 and No. 6 Mines operate in the F and E seams respectively, <br />within the lower coal group of the Williams Fork formation. The nearest <br />important aquifers are the overlying Middle Sandstone and the underlying <br />Trout Creek Sandstone. <br />The Middle Sandstone consists of a complex assemblage of sandstone and <br />sandy shales that exhibit a generally coarsening upward nature. The unit <br />is interpreted as a marginal marine sandstone "barrier and/or distributary <br />mouth sediments". It is underlain by a significant impermeable shale, <br />ranging from 15 to 30 feet thick, which is in turn underlain by <br />irregularly distributed continental deposits such as interdistributary <br />bayfills (ranging from shales to sandstones), fining-upward point bar type <br />sandstones and coals. The Middle Sandstone lies from 60 to 150 feet above <br />the F seam. <br />The Trout Creek Sandstone (Iles formation) underlies ttie E seam by about <br />300 feet. It averages about 75 feet thick and it too is interpreted as a <br />marginal marine sandstone. The intervening strata consist of coals, <br />shales and sandy shales, with only occasional sandstone. <br />1.3 Prior Studies <br />Prior mine inflow studies have been conducted in 1983, 1984, 1985 and <br />1986. During the 1983 studies, mining occurred in both the eastern and <br />western portions of the mine. During 1984 the majority of mining occurred <br />in the eastern portion of the mine. From 1985 on, all of the mining <br />activity was contained in the eastern part of the mine, and the primary <br />mining method has changed from room and pillar to longwall. In 1986, <br />development activities were initiated in the E seam. The 1987 inflow <br />study is the first study period that measurable inflow ~Nas encountered in <br />the E seam development activities. The E seam (No. 6 Mine) development <br />was producing less that 1 (one) gpm during the 1987 inflow study. <br />The results of the 1983 inflow study are provided in Table 1. The reader <br />is referred to that study and its associated map for• location of the <br />sampling sites. <br />1 <br />