The Sirius Minerals engineering team has been in Germany for factory tests of its first 60 m tall Herrenknecht Shaft Boring roadheader. The 350 t excavator will now undergo cutting tests before transportation to the Woodsmith polyhalite mine where it will sink one of the main shafts.

Sirius’s shaft sinking contractor DMC Mining Services Ltd (DMC), will use the innovative, proven Herrenknecht Shaft Boring Roadheader (SBR) to construct the main shafts. This machine was developed by Herrenknecht, the world renowned manufacturer of tunnel boring machines, as part of their involvement in mineral resources company Rio Tinto’s ‘Mine of the Future’ programme in 2013. It was subsequently chosen by BHP Billiton to excavate the shafts for their Janssen potash mine in Saskatchewan, Canada. “This experience has allowed Herrenknecht and DMC to fine tune and improve the machine, learnings which we will be able to leverage on our own shaft sinking programme.”

The SBR is equipped with a roadheader boom and a rotating cutting drum – this allows the cutting of variable shaft diameters from eight to twelve metres. The boom is telescopic and allows for the excavation of the entire shaft crosssection with a depth of one metre in a single cycle. The SBR is suspended from ropes and is connected to winches on surface – as it descends, permanent shaft lining is inserted in sections from an upper working deck. A pneumatic conveying system lifts all excavated materials to sinking buckets that are hoisted to the surface.