To guarantee the safety of the people having to work in the congested area of the shaft, contractor DMC Mining decided to use steel fiber reinforcement in lieu of the traditional rebar. Besides have less people crowding the project site, the whole operation becomes faster– as it removes the steel-fixing step.
To provide optimal ductility to the concrete, both the primary and final lining of the shaft tunnels are reinforced with 30 kg/m3 to 50kg/m3 of Dramix® 5D steel fibers. Adding 5D to the concrete resulted in concrete strength of 70Mpa. The shaft walls are slip formed with a scheduled production of up to 9,84 ft per day.