Elon Musk of course is already globally famous as the Founder, CEO and Lead Designer of SpaceX and Co-Founder and CEO of Tesla amongst other things. But he is also in the tunnelling market – Chicago has just selected his new Boring Co to build a $1 billion underground transit system that will transport people from Chicago’s downtown Loop district to O’Hare International Airport at 240 km per hour. This news comes on top of the company’s first major project to excavate a high-speed tunnel network in Los Angeles. Elsewhere, in July 2017, Musk said that The Boring Company had received verbal government approval to build an underground Hyperloop connecting New York, Philadelphia, Baltimore and Washington DC. And in October 2017, the company obtained a utility permit for the construction of the Baltimore-Washington tunnel from the Maryland’s Department of Transportation.
But from a mining perspective we are interested in what the company says about underground development. On its website it asks the question: How can we reduce the cost of tunnelling? But equally valid is: How can we reduce the cost of rapid underground mine development? This of course is something the mining industry has been trying to address for years. TBMs have already been used for specific projects in large mines – OK Tedi, Los Bronces and Stillwater being good examples, while the latest generation of continuous hard rock mining machines are progressing fast, from Epiroc’s Mobile Miner range such as the 40V which is to be used at Hecla Mining and Sandvik’s MX650 which is heading for one of Petra Diamonds’ operations for trials.
What does The Boring Co have to say on its vision for tunnelling technology in terms of reducing cost? “First, reduce the tunnel diameter. The current standard for a one-lane tunnel is approximately 28 ft. By placing vehicles on a stabilised electric skate, the diameter can be reduced to less than 14 ft. Reducing the diameter in half reduces tunnelling costs by 3-4 times. Second, increase the speed of the Tunnel Boring Machine (TBM). TBMs are super slow. A snail is effectively 14 times faster than a soft-soil TBM. Our goal is to defeat the snail in a race.” The company offers the following suggestions to increase TBM speed:
- Increase TBM power. The machine’s power output can be tripled (while coupled with the appropriate upgrades in cooling systems).
- Continuously tunnel. When building a tunnel, current soft-soil machines tunnel for 50% of the time and erect tunnel support structures the other 50%. This is inefficient. Existing technology can be modified to support continuous tunnelling activity.
- Automate the TBM. While smaller diameter tunneling machines are automated, larger ones currently require multiple human operators. By automating the larger TBMs, both safety and efficiency are increased.
- Go electric. Current tunnel operations often include diesel locomotives. These can be replaced by electric vehicles.
- Tunnelling R&D. In the United States, there is virtually no investment in tunnelling Research and Development (and in many other forms of construction). Thus, the construction industry is one of the only sectors in our economy that has not improved its productivity in the last 50 years.
The first three boring machines used by The Boring Company are Godot, a conventional and second hand TBM used for research purposes; Line-storm, a highly-modified conventional boring machine, a hybrid design, the company says boring 2–3 times faster than pre-2018 boring machines and Proof-rock, a “fully-Boring-Company-designed machine”, it says anticipated to be ten times faster than conventional boring machines, with hopes of making it even faster. This is cited as currently under development.
Of course the established TBM experts like Herrenknecht and Robbins along with key players among the mining machinery OEMs have the right to be dismissive of Musk’s grandiose plans with all their vast experience gained all over the world over many years, overcoming countless hurdles in rock type, obstacles and seismicity risk. Having said that, Musk’s other companies have achieved heights no-one ever thought possible; and it is because of this he has been entrusted already with some major works. So just don’t be surprised if one day soon The Boring Company also becomes The Mining Company.
