Tata Steel has been striving to optimize its operations amidst scarce
resources and capacity imbalances. To provide decision support, we dev
eloped a mathematical model based on mixed-integer linear-programming
(MILP) and hierarchical optimization between 1983 and 1986. It conside
rs marketing constraints, capacities, yields, profitability, routes, e
nergy, and oxygen balances. Its use just for optimal distribution of p
ower has provided a benefit of US $73 million in the first year of imp
lementation (1986-1987). Tata Steel has realized other benefits, such
as optimal distribution of scarce oxygen and liquid iron, optimal powe
r cogeneration levels, break-even prices and quantities of purchased s
crap, and optimal conversion of semifinished steel into finished produ
cts by other companies functioning as conversion agents. In the early
'80s, the model shifted Tata Steel's emphasis from maximizing tonnage
to maximizing contribution to profits.