Laser-drilling technology may benefit tunnelling
24 September 2020Idaho-based Merger Mines Corp says it has laser and robotics technology that has the potential to benefit not only mining but also large-bore tunnelling, dams and other construction applications.
The technology is hailed as having the potential to revolutionise the way excavation is undertaken globally and to lower costs significantly. Although laser technology for mining has been around for some time, its commercial application has so far been slow to materialise.
At the heart of the system is the Gradual Optical Collimator (GOC) which directs a 1kW laser beam that spalls geological formations, thereby aiding the creation of portals, adits, drifts, cross-cuts and vents without the use of explosives. The single, remotely-operated GOC unit takes up only 1m x 2m and is said to be able to mine at the rate of around 2.6t/hour, producing ‘pea-sized chips’ of spoil material for easy removal. Ancillary equipment such as power generators and air compressors can be located remotely from the face if necessary.
In addition to lowering excavation costs, the GOC is claimed to reduce operatives’ exposure to the potentially dangerous situations typically encountered using explosives and conventional mining equipment.
GOC works by applying rapid heating to the rock surface followed by rapid cooling causing stress compression in the rock leading to fracturing and spalling. The cooling is created by a jet of compressed air applied to the rock face after the application of the laser beam.
The rapid heating-cooling technique is analogous to the ancient method of fire-setting, which involved lighting fires against the rock face and then dousing with water to create fracturing due to thermal shock.
