Wall support for raise bored shafts

Abstract

Getting access to underground area's is a useful construction activity for many human activities. Each year we use over 500 megatons of metals in our everyday life, which has all been mined from pits and underground ore deposits sometimes as deep as 3000m. To gain access to these deep deposits requires an efficient method of construction of vertical shafts to get there, to transport men and equipment, to carry fresh air and to carry the ore out. Besides mining we also use shafts to transport water through damsites, for transportation purposes through tunnels in urban areas and to store chemical and radioactive waste. Research into shaft construction has always been limited but is now becoming of increasing importance. Because ore bodies are becoming depleted, shafts are being constructed ever deeper and in ever more challenging geologies. Secondly, unsafe practices that endanger the lives of men working in shafts have become unacceptable. This research looks into ways of constructing vertical shafts in area's with soft and weak overburden that have been uneconomical previously. The focus is on ways to reinforce soft soils and soft and fractured rock. Without further treatment such geologies normally cause collapse of the shaft. The research looks at construction methods within the confines of increased safety demands, low cost and varying geology and hydrology.