The new alternative in Raise Boring

Method

Raise Boring

The raise boring technology was developed to meet the demands of the underground mining industry but has also found numerous applications in civil construction industry and hydropower projects.

Raise boring provides a safe means of excavating a circular hole between two levels of a mine without the use of explosives. A raise boring machine is set on a platform on the upper level to drill a small hole, known as the pilot hole, through to the cavity below. Once the drill has broken through, the pilot bit is removed and is replaced by a reamer head, of the desired diameter of the shaft, which is rotated and raised back toward the raise boring machine. The drill cuttings from the reamer head fall to the bottom of the hole and the reaming process creates a cylindrical hole with smooth walls.

Raise boring was developed for the underground mining industry but is nowadays increasingly also used on infrastructural projects to create tunnel ventilation or elevator shafts, and in sewer and water projects, to mention a few examples. Advances in the design and construction of reaming heads and rock tools means the technique can now be used in very hard rock and in deep underground locations. Due to its many advantages over the conventional drill and blast methods, raise boring continues to find new applications.

Among the important advantages are:

Safety
Raise boring provides a safer alternative as no personnel need to access the raise while it is under construction and there is no exposure to falling rocks or to dangerous explosives.

Speed
Raise boring works in a non-cyclic fashion, which gives it a faster advance rate than other methods.

Physical characteristics and quality of the completed shaft
Raise boring creates a hole with smooth walls which usually does not require lining. The hole is more stable than a drilled and blasted raise and has better air flow, making it ideal for ventilation raises.

Less disturbance of the rock structure
Raise boring can safely be used in areas of geological sensitivity.

Cost reduction
Less total manpower, less rock to handle, and less construction time, all add up to less costs.