Modern Mining June 2016

TECHNOLOGY

for shaft enlargement for which a pilot hole is used. The SBE (Shaft Boring Machine for Shaft Enlargement) project is a joint venture between Schachtbau GmbH and Murray & Roberts Cementation and the aim is to update and adapt existing pilot-hole technology to achieve high sinking speeds and maximum work safety,” says Roos. The SBE is planned for shaft diameters of between 7,5 m and 9,5 m and for shafts up to 2 000 m deep. Material conveyance takes place by gravity through an existing pre-hole. The machine, 15 m in length, braces itself in the shaft before each drilling stroke, which enables the thrust cylinders to push the rotating cutterhead against the borehole floor to cut into the hard rock. “Herrenknecht is committed to the devel- opment of blind-shaft technology and the introduction of mechanised shaft sinking for the mining industry. We look forward to dem- onstrating the safety and productivity benefits of our pioneering machines for upcoming min- ing projects in South Africa,” Roos concludes. Photos courtesy of Herrenknecht

used during regular advance operations and the excavation chamber is also a ‘no-go’ zone while cutting is in progress.” The machines can be modified to support tubbing, rock bolting, shotcrete or concreting activities and unless there are extremely poor rock conditions, excavation, mucking and rock support are carried out simultaneously. Herrenknecht shaft-sinking machines are kept on course by a built-in guidance system, which removes the need for a centre-core pilot hole used when reaming technology is applied, either from bottom-up or top-down. The excavation sequence for all machines is fully automated and the material is cut without disturbing the surrounding ground and with almost zero over-break. The transportation of cut material can be designed to suit customer or project require- ments. The removal of muck from the shaft bench can be performed dry or wet, using a high-volume air-flow, a mechanical conveyor system, or a fluid conveyance system. “Herrenknecht is also in the process of devel- oping a new generation of rodless machinery

Seen here (from left) are Herrenknecht’s four shaft boring machines – the Shaft Boring Machine (SBM), the Shaft Boring Roadheader (SBR), the Shaft Boring Cutterhead (SBC) and the Shaft Boring Machine for Shaft Enlargement (SBE).

June 2016  MODERN MINING  23