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-11- conductivity, and laboratory analysis of total dissolved solids. The Division, there- fore, requires the folla.~ing stipulation be placed upon the permit application to find the operator in conformance with Rules 2.05.6(3)(b)(iii) and 4.04.13(a): WYOhfING FUEL COMPANY SffAhL CONTINUE QUARTERLY GROUND [JA TGR QUALITY ANA L}'S ZS. THESE ANALYSES SHALL INCLUDE ALL FIELD AND LADORATORY PARAMETERS REQUIRED BY THE DIVISION CONTAINED IN TABLE 1 OF Tf17S PERFIIT. When the applicant has completed a year's baseline, it may petition the Division for a reduction in sampling frequency, parameters analyzed, and number of stations sampled. To ensure that the Division obtains copies of the ground water quality and quantity data in a timely manner for its review, the Division imposes the following stipulation: WYOMING FUEL COMPAIJ}' SHALL .SUBMIT GROUND WATER LEVE 1. A1JD QUALITY DATA ON A QUARTERLY BASZS TO T)IE D.I VISION. The Division finds that Wyoming Fuel company, with the acceptance of the above stipu- lations, will have a ground water monitoring system designed to adequately monitor the effect of mining on the hydrologic balance - ground water - and, therefore, will be in conformance with 2.05.G(3)(b)(iii) and 9.05.13(a). Effects of Mining on the Hydrologic Balance - Ground Water A. General Backgrormd The Wyoming Fuel's Canadian Strip mine is located a.i ong the nose of the hfcCall um Anticline. The present operations are located on the southeastern lin>!~ of. the anti- cline and future mining will be located along the western limb. The McCallum Anticline is a tight asymmetric pIunying anticline. The eastern limb is the more steeply dipping limb and the anticline plunges to the southeast. The anticline is cut by faults. The number of faults increases towards the nose of the anticline. The McCallum Anticline is flanked on the northeast by the Johnny Moore Sun cline, which is a very tightly folded syncline which also plunges to the southeast (see Exhibit C-2). Sedimentary rocks within the pernu:t area consist of units of the Cretaceous aged Pierre Shale and the Tertiary aged Coalmont Formation. The Pierre Shale is of marine origin, as reflected in the salinity of the rock units and the soils developed from these rock units. The Upper Sandy ~tfen~er of the Pierre .Shale is separated from the Sudduth coal seam by 30 feet of rathez~ impervious shale, and is composed of inter- bedded sandstones, siltsones, and shales. The Upper Sandstone Member can be considered a regional aquifer, since it is continuous and can transmit limited quantities of water. Pump tests conducted by Kerr Coal on this unit yielded a permeability of 0.15 gpd/ft2, thus indicating that the Upper Sandy Member of the Pierre Shale is a poor aquifer. Low permeabilities were obtained by Wyoming Fuel in 2 slug tests run at sites 1C and SA on the siltstone underburden separating the Sudduth coal seam from the Upper Sandy Member, 0.09 gpd/ft2 and O.OI gpd/ft2, respectively. Kerr Coal Company in their pumping test obtained no drawdowns in the Sudduth coal seam while pumping the Upper Sandy hfember well 20 feet away. The results of the two separate sets of aquifer analyses indicate that the silt-