Now that the several major elements of an integrated iron-and steelproducing works have been explored and the relevant alternatives captured in the linear programming framework, we are nearly ready to ask the resulting model the sorts of questions raised in the introduction. There are, however, two important matters we must address before our explorations of the cost of residual discharge reduction and the impact of relative prices on residuals generation can be meaningful. First, we must find out what the bench mark situation looks like. That is, we want to know the costs of production, the pattern of input use, the residuals generation rates and other characteristics of the mill in the absence of assumptions other than those already outlined. Second, it is necessary to attempt some assessment of the realism of the model. Thus, although we have mentioned a number of checks on individual numbers used in the process and treatment vectors, we have no assurance that the whole model will produce anything but nonsense. Such assurance is clearly necessary, since there may be other numbers out of line or the basic structure may be flawed.