Abstract: An underground shaft development method comprises: (a) drilling blastholes extending into a rock formation, each drilled from a starting location defining a first blasthole end to an ending location defining a second blasthole end; (b) loading the blastholes with alternating layers of explosives charges and stemming material to provide multiple blasting decks across and within the formation, including at least a first blasting deck corresponding to the first blasthole ends and a final blasting deck corresponding to the second blasthole ends, wherein each blasting deck carries wireless blasting devices; and (c) detonating the explosive charges in a series of blasting stages based on blasting deck by initiating the wireless blasting devices in each blasting deck, proceeding consecutively from the first blasting deck to the final blasting deck, wherein after each blasting stage excavation takes place to progress the shaft in an intended direction.