Box hole boring

The most difficult raise method, known as Box-Hole excavation, is to drill a pilot hole to any level up from the raise borer. Once the desired length is achieved the drill string is retrieved, and a reamer attached and pushed upwards. The broken rock falls down the enlarged hole onto a special collection chute attached to the top of the raise borer.

Box Hole boring is used where underground access is available and an upwards hole is required. This method does not require a typical pilot hole as with traditional raise boring machines over short distances.

Applications

★Mining Sector: Most Box Holes are drilled in underground mining applications where bottom access is available in a production section. The holes are drilled from the bottom up to where it intersects with the ore body. When mining activity reaches this hole, it may then be used as a transfer pass for dropping material from the reef/ore horizon downwards where it can be collected and transported; or as a ventilation shaft to the mining location.

★In some cases the shaft is equipped with a chute to hold a certain volume of material, similar to a small silo. In other cases it is used for transfer passes into an existing ore pass or where construction of material handling infrastructure is already in place and explosives cannot be used to create an excavation. In addition, it is used for troth passes in block cave mines.

Advantages

★Box Hole boring has similar advantages to that of traditional raise boring although it is drilled upwards and no typical holing point is required.

★The safety of personnel is assured, as personnel isn’t required to enter the excavation where they may be exposed to falling rock.

★Safer, faster and a lower cost.

★Drill rods feature a unique non-rotating stabiliser design.