Murray & Roberts Cementation has secured the contract to deepen the existing ventilation shaft at Gold Fields’ South Deep mine to a depth of 2,990 m. The shaft is being extended to match the man and materials shaft adjacent to it, which is currently the deepest rock hoisting shaft in the world. The shaft diameter will be 9.10 m. Allan Widlake, Business Development Director at Murray & Roberts, says that because the company is currently doing mine development work at the same depth to which the new shaft will be extended, Murray & Roberts can manage the full interface required between the mine development and the shaft deepening.

“The contract itself will be challenging as work will be done at an extreme depth and, more significantly from an operational and safety perspective, it is below an existing shaft,” Widlake says. “We have selected a methodology that will allow us safe access below the existing shaft and are using different methodologies to sink through the various levels.”

Widlake explains that the company will blind sink the lower portion from 2,890 m to the final depth while the upper sections from 100A level down to 2,890 m at 105 level will be raise drilled to create a central small diameter hole, then stripped out to the full width using conventional sinking techniques.

After the two sinking phases have been completed, Murray & Roberts will equip the lower section of the shaft. Gold Fields is currently equipping the shaft from surface down to 95 level, while Murray & Roberts will take over from 95 level downwards.