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<br /> <br />Permeability tests performed by the applicant on the over- <br />burden, coal, and underburden within the Coalmont Formation <br />demonstrate that these strata do not meet the definition of an <br />aquifer due to low permeability characteristics; each stratum <br />demonstrated a permeability of less than 0.1 gpd/ft2, Permea- <br />bility values from aquifer tests done in wells (Table 15, <br />Appendix C) are slightly greater than the permeabilt,y values <br />obtained from aquifer tests performed from cores (Table 14, <br />Appendix C), which indicates that actual groundwater movement is <br />enhanced by minor fractures or fault systems. Because of the <br />extremely low transmissivity values of the Coalmont strata, this <br />fracture/fault system may significantly control groundwater move- <br />ment. In spite of this, permeability values remain so low that <br />groundwater flow rates in this region are considered insignifi- <br />cant. Although varying artesian heads are exhibited throughout <br />the lease area within the Coalmont, these presures are in re- <br />sponse to highly localized conditions resulting from the inter- <br />layered sandstone and siltstone strata (see the aquifer test <br />results presented in Appendix C). Because the area of the pro- <br />posed operations of the Canadian Strip Mine is so small (approxi- <br />mately 170 acres will be affected) and because the adjacent Marr <br />Strip operation has adequately defined the flow patterns in the <br />area of both mines, the applicant's contention that the mapping <br />of any consistent piezometric surface at the Canadian Strip site <br />is unnecessary is justified. <br />The Upper Sandy Member of the Pierre Formation, which is <br />separated from the base of the coal by up to thirty feet of shale <br />underburden, is the most important water-bearing zone within the <br />permit area. However, permeabilities in this aquifer are also <br />relatively low. There appears to be no appreciable hydrologic <br />connection between the underlying Upper Sandy Member of the <br />Pierre Shale and the Lower Coalmont Formation, except possibly <br />through highly localized fault or fracture systems, due to the <br />relatively impermeable nature of the shale layer separating the <br />two. <br />-24- <br />