Blind boring

When a raise is required but there is no access to the upper level, it has to be bored blind from below, usually without a pre-drilled pilot hole. A special type of head is required for blind boring. It drills the pilot hole and reams out the raise at the same time. The head is rotated and pushed upward. The cuttings fall out of the hole by gravity.

Normal blind raise diameters are from 0.6 to 1.8 m. Since the drill string is under compression during blind boring, special large-diameter stabilizers are needed to support the drill string. The blind-boring method is used to produce so-called slot raises, ore passes.

Applications

★Mining sector: Shaft boring or enlargement is used for the construction of access or ventilation shafts for the mining industry.

★Civil sector: In the urban infrastructure industry it is used for access and ventilation shafts to metro tunnels and underground storage areas such as parking garages.

★Energy sector: In the energy sector it is used for surge, ventilation, access and pressure shafts.

Advantages

★Blind boring does not require the use of explosives. It is a continuous production process with fewer personnel working in the shaft during construction.

★Contributing to improving mine production and logistics.

★The innovative system addresses the need for a safer, faster, flexible and lower cost method to access underground orebodies without existing underground access.

★Added benefit of facilitating mining level break away operations and simultaneously lining the shaft and diameter/depth changes without major modification.