At Codelco's El Teniente mine in Chile, the presence of fault zones, areas with varying rock hardness and loose rock presents challenges for traditional drilling methods, mainly in terms of shaft stability during its excavation and until its final lining.
By using the pipe jacking principle on the BBR machine and the simultaneous use of a lowering unit during reaming, shaft walls are always supported, enabling excavation and lining installation in challenging geologies considered too unstable for conventional shaft drilling methods.
In 2020, DMC Mining Services Chile, acquires a BBR and lining lowering unit, to be used in duo at Codelco's El Teniente mine in Chile, where shafts with a length between 20 and 50 meters with a final diameter of 3 meters have to be bored and lined.
To this day, and despite the various challenges faced, more than 400 meters of shafts have been successfully bored and lined in the very complex geological context of this mine without any incident.
Herrenknecht's BBR, in combination with a lowering unit, offers a viable alternative methodology for creating shafts in unstable grounds of random hardness, while keeping the risk of collapse under control compared to the conventional shaft sinking methods and technologies.
