The resurgence of interest in hydroexcavation—the use of high-pressure waterjets for cutting and removing material—involves new areas of development that have taken it a long way from its original use. While hydroexcavation was first used for bulk material removal, a combination of mechanical and waterjetting tools followed, and recently waterjets have been used for localized fragmentation in drilling and rock slotting applications. Rock slotting is the practice of cutting a channel in rock, generally to provide a free surface that the rock can be broken into, or to isolate a mass of rock that can then be removed.