In underground room-and-pillar mining methods, the sectional conveyor belts are extended or retracted periodically to maintain shuttle car tramming distance to a minimum. A conventional conveyor belt extension or retraction is a heavy, arduous job that, if mechanized, has the potential to improve productivity and safety. To reduce the burden of heavy work of this activity and mechanize it, the Bureau of Mines developed a conveyor belt service machine (cbsm) through a research contract with tractor mbs. A cbsm is a self-contained, battery-powered, rubber-tired vehicle capable of handling, storing, and transporting conveyor belting, wire rope, and associated belt structures in seams as low as 48 in. Belt extensions and retractions are accomplished by moving the tailpiece of a belt conveyor with the cbsm to the next position while dispensing or retrieving the belt, wire rope, and associated belt structures. The cbsm improves the belt extensions and retractions by making them easier and faster, and it utilizes fewer workers. The cbsm was surface tested at the Bureau's mining equipment test facility to evaluate its performance and reliability. Modifications were made to the cbsm to correct deficiencies found during surface testing.