Combined optimisation of an open-pit mine outline and the transition depth to underground mining

Abstract

Miners harvest minerals from ore-bodies in the ground by a variety of specialised mining methods, with most falling into the categories of open-pit and underground. Some ore-bodies are harvested by a combination of open-pit and underground methods. In these cases there is often material that could be mined by either method, and an economic choice has to be made. This is referred to as the transition problem and it has received some attention in the mining literature since the 1980s and more recently has had attention in the mathematics literature. The transition problem is complicated by the need in many cases to leave a crown pillar (un-mined rock above the underground mine) and for this cr..