Longwall mining accounted for nearly 21 pct of U.S. underground coal production in 1987. Although national longwall production normally averages about 1,900 tons-per-shift (tps), some U.S. longwall sections consistently produce more than 4,000 tps. To identify the factors responsible for this high level of production, the Bureau of Mines surveyed eight of the highest producing longwall sections in the United States. Earlier, the Bureau had examined continuous miner sections to seek out causes for high production levels. It was discovered that labor-management relations were the key factor for the continuous miner sections, especially in high coal. The Bureau wondered if this was also true for exceptionally productive longwalls. Results indicate that it was not. In longwalls, new equipment and technology are the key factors in achieving greater production.