Mining thin coal seams is both difficult and uneconomical. As a result, most thin-seam coal reserves in the United States are not being mined. It is estimated that nearly 910 gt of coal reserves exist in 355- to 710-mm-thick seams. The U.S. Bureau of Mines is attempting to develop new techniques for mining 150- to 1,065-mm- thick coal seams. This paper summarizes the research work on existing thin-seam mining techniques, testing on small- and full- scale physical models of the Bureau slot mining concept, and computer modeling of the full-scale process.