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PROJECTED TNONPSON CREEK N0. 1 MINE FILLING TIMETABLE Table 4.6.1-2 was prepared to predict mine inflows at the Thompson Creek No. 1 Mine. These predictions were made to analyze the timetable for filling the mine, the maximum head on seals, and the water augmen- tation needs in the future. The June 1985 mine inflows study was the basis for this projection. These flows were grouped in areas with an average elevation of inflow assigned to each group. The June inflows were assumed to be average for the year. Accounting for seasonal variation would require very complicated calculations associated with head and viscosity. Mine inflows are assumed constant until the water level rises above their average elevation. The flows, when the water level rises above the point of inflow, were calculated using Darcy's equation for seepage through a sand filter *(Practical Hydraulics, Andrew L. Simon, Wiley, 1981, Page 130). The coefficient of permeability, the flow surface area and the flow length all remain constant for an individual flow; therefore, the flow is directly proportional to the head. The following assump- tions were made to determine the head on each flow group. `1. Inflows north of the shear zone originate where North Thompson Creek crosses the outcrop of the A-Seam. 2. Inflows near the shear zone originate where the projected shear zone crosses Middle Thompson Creek. • 3. Inflows near the south end of the longwall panel originate where Middle Thompson Creek crosses the outcrop of the A-Seam. These assumptions are believed to be very conservative in that many of the flows may not be directly connected to the North or Middle Thompson Creeks. The flows from the B-seam were assumed to be from surface water flowing into the outcrop. The 7.5 gpm shown in June 1985 was from a source above the creeks, therefore, it was assumed to be constant. The large spring inflows in the B-seam were assumed to be eliminated by covering old portals along the outcrop of the B-seam in the fall of 1986. As the mine filled above the source for inflows from the North Thompson Creek and the shear zone, the flows were calculated to be negative due to the negative head. These negative flows are considered to be conservative on the low side since there is potential for seepage along the coal seam outcrop above North Thompson Creek. The water capacity of the mine was calculated from the extent of workings. Figure 4.6.1-3 was prepared to show filling levels. The first two fill zones were calculated with respect to observed fill levels. From the last fill level observed 7425', 25' intervals were used to calculate volumes. In the longwall panel an effort was made to account for caving. Therefore, the lower end of the longwall panel C 4-115a (New 3/25/87)