Abstract: A novel method of excavating underground chambers in strong rock is provided which is particularly suitable for use in stope and pillar mining operations. The method takes advantage of blasting techniques and specifically the use of large diameter spherical explosive charges by locating a spherical charge in a cavity provided in the ceiling or roof of an underground chamber. Upon detonation of the charge, an optimum volume of cavity is produced in the chamber ceiling from which well fragmented ore rock is displayed by gravity to the floor of the chamber from where it is easily removed.