Research conducted over the past 20 years in France, Great Britain, and the United States on the use of the large-hole burn cut has established certain advantages for this system. Advantages include longer pull and more complete fragmentation from blast rounds. However, research is needed to establish a set of parameters for optimum performance. As part of the Bureau of Mines advancing mining technology for marginal resources program, the Twin Cities Mining Research Center, Twin Cities, Minnesota, acquired a horizontal rotary drill capable of boring holes up to 24 in. in diameter. This was used for a series of underground experiments at White Pine Mine, White Pine, mich., During 1973. Exceptional results were obtained with a 12 1/4-in void hole that yielded up to 18 ft of pull in a 10- by 20-ft drift. Fragmentation was excellent, and the compactness of the muck pile facilitated loading.