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10. Fluxes through the ends and bottom of the pit are insignificant and not accounted for <br /> in the program. <br /> 11. The aquifer is homogeneous, isotropic, and infinite in extent. <br /> 12. The transmissivity value for a pit is set equal to the product of the saturated depth <br /> of pit and the average hydraulic conductivity. <br /> 13. The number of pits mined per year must be a whole number, with the number of days all <br /> pits are open for a year being less than or equal to 365 days (i.e., 1 pit open for <br /> 365 days, 2 pits open 182 days each, 3 pits open 121 days each, etc.). <br /> The overburden pit inflow values were calculated using unconfined ground water flow <br /> equations and the Dakota coal pit inflow values were calculated using confined equations. <br /> Pit inflow calculations are based on the following procedures developed by McWhorter <br /> (1982). Equations 1 and 2 describe one-dimensional unconfined and confined flow. <br /> 1 ) d dh� dh 0 x� Lu <br /> K dx h dx — Sya dt <br /> 2) d 2 h S dH Lu< x` Lc + Lu <br /> T dx2 = dt <br /> where: <br /> K is the hydraulic conductivity, L/t; <br /> 2 <br /> T is the transmissivity, L /t; <br /> Sya is the specific yield, dimensionless; <br /> S is the confined storage coefficient, dimensionless; <br /> h is the head in the confined zone, L; <br /> H is the pressure head above the confining unit in the confined zone, L; <br /> x is the location in cartesian coordinate space, L; <br /> t is time, t; <br /> Lu is the distance to the unconfined-confined zone interface, L; and <br /> Lc is the distance from the unconfined-confined interface to the undisturbed zone, L. <br /> Integrating equations 1 and 2 with respect to x over the intervals in which they are <br /> applicable, applying Leibnitz's rule, and summing the two solutions results in the <br /> following equation: <br /> 17-6 Revised 04/11/88 <br />