HYDRAULIC HOISTING AT VAAL REEFS, SOUTH AFRICA.

The Vaal Reefs mine in South Africa's Klerksdorp area is currently the world's largest gold mine in terms of ore processed. In 1973 the operation milled 5. 5 million tons of ore from its underground operations for the production of some 68,290kg (2. 2 million oz) of gold. Some three years ago, the company installed an hydraulic hoisting system at the mine's No. 1 shaft, designed to pump abrasive gold-bearing slurry to the surface plant from a depth of 2,150m (7,200ft) in a four-stage lift. The project has proved to be successful, both directly in terms of additional ore hoisted, and indirectly with regard to other hoisting benefits, and company engineers are now involved in installing an additional slurry pump column in the same shaft.