Contour Cutting Mechanisms As A Means Of Improving Underground Stability

There has been a considerable amount of research developed which shows that the close contour cutting of an excavation prior to removal of the central core will increase ground stability while concommitantly, reducing the number and size of blastholes required to create the excavation. To date, the industrial development of this technique has however, centered on the development of equipment based on simple cutter movement and mechanical rock cutting. The advent of reliable field operable high pressure waterjet cutting equipment with the very low reactive force required to hold the head in position has opened the way for a much smaller and more manueverable system. The advent of small, micro-computers allows the programming of accurate profiles for cutting tools on excavation equipment. The combination of these two technologies will allow the generation of complex as well as simple, excavation profiles and lead to the potential pre-support of the opening before major excavation is completed. A brief description of the necessary components and their functions is encorporated in the initial prototype design as given.