Underground metalliferous mining methods often result in the formation of vertical openings to facilitate the extraction of orebodies. These development and production techniques can result in the creation of vertical open voids, which include stopes, orepasses, ventilation raises and other excavations. There are risks associated with the use of mobile plant in the vicinity of these voids, especially during backfilling and when bunds are constructed at the edge of a stope or void. These voids can present unacceptable risks if not adequately managed.