A Southern African Silver Anniversary 2014 SOMP Annual Meeting

Mining in the 21st century is facing many challenges, among which are low-grade and high tonnage orebodies. One great (r)evolution in mining occurred in the early 20th century when Daniel Jackling proposed the concept of economies of scale for large-scale (bulk) mining at Bingham Canyon. At that time, there were many shallow deposits around the world suitable for open pit mining. Hence, this method grew rapidly and the majority of iron, copper, and gold production came from open pit mines. Open pit mining method has many advantages such as increased safety, higher production rates, more flexibility, lower cost, less operational risk, etc., so normally it considered as preferred option; but break-even depth, high stripping ratios, and environmental issues have become significant challenges facing this method in 21st century. In underground mining, block caving is the only method with the costs comparable tosurface mining methods, especially open pit mining. A switch from open pit mining toblock caving mining could be another great development in this century. However, even though an increasing number of mines are being developed using block caving, this method involves many technological and environmental challenges. The depth of the orebody is one of the most important factors governing selection of the mining method. This paper offers a numerical (quantitative) ranking system for mining method selection when both open pitting and block caving are feasible, which is true for many low-grade and super large hard rock mining operations