Shaft-sinking crews flatten the SBR learning curve with experience
Slavkaliy began the planning phase for the Nezhinskiy potash mine near Soligorsk, Belarus, eight years ago. In July 2017, the company began working with Deilmann-
Haniel , a member of The Redpath Group, to construct two freeze shafts and approximately 9,000 meters (m) of horizontal excavations. The difference between this shaft-sinking project and previous ones in the region is that it will use Herren-knecht’s Shaft Boring Roadheader (SBR).
As the name implies, it’s based on the rock-cutting priniples of a roadheader. A similar system was used to sink the Jansen shaft in Saskatchewan, Canada, and others are considering it for softer orebodies. The SBRs that will be used in Belarus, however, have been improved based on the experience gained on the Jansen project. They were optimized specifically for clay and sandy material with a compressive strength of 100 megaPascals.
The combination of the freeze shafts and the rock’s low compressive strength allows the use of the SBR technique to sink these shafts. This technique has proved to be safe and efficient. Shaft boring essentially eliminates the use of explosives, which also greatly reduces the number of people at shaft bottom during development. The SBR on average is expected to advance 3 meters per day (m/d), which is a significantly higher rate than conventional shaft-sinking methods. How can this be? Boring, transporting the cuttings to the surface, and installing the concrete lining can be carried out simultaneously.