Earlier this month, Elon Musk’s Boring Company dominated headlines with its proposal to build a transit tunnel in Fort Lauderdale, Florida. Weeks earlier in Las Vegas, the company unveiled its first operational tunnel, a 1.7-mile-long passageway underneath the Las Vegas Convention Center (LVCC) designed specifically for Tesla vehicles.
While one might think that everything Musk touches is on the forefront of its industry, tunneling experts say what Boring Co. is building isn’t really that different than subway and pedestrian tunnels that are commonplace in large cities.
“I don’t see any new technology being mentioned,” Jian Zhao, a civil engineering professor at Australia’s Monash University told NBC last month after Boring Co. unveiled the Vegas loop.
In Florida, the company plans to dig a three-mile tunnel with a diameter of 12 feet running from downtown Fort Lauderdale to just below the entrance to the beach.
“A three-mile-long, 12-foot-diameter tunnel in the shallow subsurface of Florida is not overly complex by the standard of the global tunneling industry. It’s not the sort of the bleeding-edge complexity of tunnels,” Michael Mooney, a Civil and Environmental Engineering professor at the Colorado School of Mines, told Observer.
In general, the longer, wider and deeper a tunnel is, the more difficult it is to build. “A 12-foot-diameter tunnel is a small tunnel,” Mooney explained. “You often see that for utilities or pedestrian traffic. Road tunnels and subway tunnels are usually much bigger.”
For example, the recently completed State Route 99 tunnel in Seattle, a product of state-of-art tunnel boring technology, has a diameter of 57.5 feet. That’s almost five times wider than Boring Co.’s Vegas loop.
However, South Florida has some tricky geological conditions that could pose challenges for digging. The area’s prevalent limestone rocks make it hard to optimize a boring machine due to the natural holes in it, tunnel experts say. Fort Lauderdale also has high levels of groundwater and heavy rainfalls, which increase flooding risk.
But it’s not undoable. The Port of Miami undersea tunnel, opened in 2014, is built in the similar geological environment. It’s also much larger (43 feet in diameter) than what Boring Co. is proposing.
“It’s a challenging environment. But [Miami] is a good example that tunnels can be built in South Florida,” Mooney said. “Tunnels have been built in every geological environment. Tunnel boring machines have been very successful both in tunneling through soil and rock in widely varying situations.”
Still, Boring Co. is unique in its own way. Like every other Musk-led company, Boring is vertically integrated: the company is the simultaneously the manufacturer of tunnel boring machines and the builder of tunnels, which is very unusual for the industry.
A direct benefit of vertical integration is low cost. The Fort Lauderdale project is expected to cost $30 million. That’s a fraction of typical tunneling costs, according to local leaders. The Port of Miami tunnel, which is less than a mile, cost $1.1 billion and took four years to build.
Details of Boring Co.’s plan in Fort Lauderdale are unclear. The city is accepting competing proposals and is prohibited by state law to release specifics during the bidding process, which is expected to be completed in mid-August.