This report, using a linear programming model to minimize total delivered world steam coal costs, analyzes future coal trade flows. Assessing the possibility of exporting Northern Great Plains coal through the St. Lawrence via the twin ports of Duluth, Minnesota and Superior, Wisconsin is the main goal of the study. World steam coal trade flows are projected for the years 1985, 1990 and 2000 through the linear programming model. The model includes demand from 25 coal importing nations and supply from 19 coal producing regions around the world.