The Boring Company is gearing up to tackle one of its toughest projects yet, a new tunnel system beneath Nashville’s notoriously tough limestone terrain. Unlike the soft-soil conditions of Las Vegas and Austin, the Music City Loop will require a “hard-rock” boring machine capable of drilling through dense, erosion-resistant bedrock. 

The Boring Company’s machine for the project is now in final testing.

A boring hard-rock tunneling machine

The Boring Company revealed on X that its new hard-rock TBM can generate up to 4 million pounds of grip force and 1.5 million pounds of maximum thrust load. It also features a 15-filter dust removal system designed to keep operations clean and efficient during excavation even in places where hard rock is present.

Previous Boring Co. projects, including its Loop tunnels in Las Vegas, Austin, and Bastrop, were dug primarily through soft soils. Nashville’s geology, however, poses a different challenge. Boring Company CEO and President Steve Davis mentioned this challenge during the project’s announcement in late July.

“It’s a tough place to tunnel, Nashville. If we were optimizing for the easiest places to tunnel, it would not be here. You have extremely hard rock, like way harder than it should be. It’s an engineering problem that’s fairly easy and straightforward to solve,” Davis said.

Nashville’s limestone terrain

Experts have stated that the city’s subsurface conditions make it one of the more complex tunneling environments in the U.S. The Outer Nashville Basin is composed of cherty Mississippian-age limestone, a strong yet soluble rock that can dissolve over time, creating underground voids and caves, as noted in a report from The Tennessean.

Jakob Walter, the founder and principal engineer of Haushepherd, shared his thoughts on these challenges. “Limestone is generally a stable sedimentary bedrock material with strength parameters that are favorable for tunneling. Limestone is however fairly soluble when compared to other rack materials, and can dissolve over long periods of time when exposed to water. 

“Unexpected encounters with these features while tunneling can result in significant construction delays and potential instability of the excavation. In urban locations, structures at the ground surface should also be constantly monitored with robotic total stations or similar surveying equipment to identify any early signs of movement or distress,” he said.

Tesla CEO Elon Musk teased a potential job for the company’s Optimus robot last week that is straight out of the movie “Robocop.”

“Robocop” aimed to show a futuristic look at law enforcement in a Sci-fi thriller that was among the first iterations of how robots could be used for police work.

The 1987 film showcased an injured cop turning into an armed cyborg, and although Tesla’s Optimus won’t be a human-robot hybrid, Musk’s idea for the humanoid project is similar.

Musk said last week at the Annual Shareholder Meeting, where shareholders voted to approve his $1 trillion compensation plan, that Optimus could be the future of law enforcement, nearly revolutionizing the way criminals are prosecuted.

He hinted that Optimus could actually be used as a chaperone of sorts, arguing that it was a “more humane form of containment of future crime.” Musk said:

“If somebody’s committed a crime, we might be able to provide a more humane form of containment of future crime. You now get a free Optimus, and it’s just going to follow you around and stop you from doing crime. Other than that, you get to do anything; it’s just going to stop you from committing crime. That’s really it. You don’t have to put people in prisons and stuff. It’s pretty wild to think of all the possibilities, but I think it’s clearly the future.”

Elon Musk: With Optimus, we might be able to stop putting people in prison.

“If somebody’s committed a crime, we might be able to provide a more humane form of containment of future crime. You now get a free Optimus, and it’s just going to follow you around and stop you from… pic.twitter.com/Y8E2ToyNkd

— ELON CLIPS (@ElonClipsX) November 10, 2025

Musk’s overall idea for Optimus is to change the way people are able to exist, from those law-abiding citizens to others who have their run-ins with the law. Instead, the Tesla CEO believes there could be a different way to handle everything, including punishment.

It was not the only thing that Musk indicated could be changed significantly by the presence of humanoid robots, as he also said a universal basic income could be established with the help of products like Optimus.

Elon Musk recently amplified the thoughts of Morgan Stanley analyst Adam Jonas, who had insight into the “Muskonomy” of his potentially interconnected ventures, something that was proposed at the recent Tesla Shareholder Meeting with xAI.

Musk’s words indicate a potential strategic fusion that could serve as a blueprint for future innovation–but it is dependent on a conglomeration between the many entities the CEO serves.

As Tesla grapples with scaling Optimus and preparing for its imminent production and the development of the Full Self-Driving suite, xAI’s computational edge could provide leverage for the millions of miles of data the company accumulates, providing a more stable and accurate development strategy for the autonomous and AI efforts it has put its chips all in on.

After Tesla Shareholders voted to deny Tesla and xAI’s potential financial partnership through an investment, Jonas said it was an issue that would have to be revisited due to its importance.

xAI has the opportunity to provide an incredible strategic and financial bolstering to Tesla, especially with how important a role data plays in the development of the company’s biggest products.

Jonas wrote in a note to investors:

“They’re gonna have to revisit this. We don’t think investors understand just how important xAI is to Tesla and the broader Muskonomy. Tesla’s relationship with xAI (financially and strategically) is deterministic to the long-term success of Tesla due in part to the natural synergies of data, software, hardware, and manufacturing in recursive loops. The values (and value systems) of both Tesla and xAI are endowed by the values of their shared creator. We believe this co-determination becomes more obvious in the next phases of physical AI/ autonomy for Tesla in the year ahead.”

Musk said, in response to Jonas’ note, that his companies are “surprisingly in some ways, trending toward convergence.”

My companies are, surprisingly in some ways, trending towards convergence

— Elon Musk (@elonmusk) November 10, 2025

Mergers and shared ecosystems between companies are not new moves out of Musk’s playbook, as it has been done in the past, especially with Tesla acquiring other entities.

It did it with SolarCity in 2016 and with Maxwell Technologies in 2019. Investments between Musk companies have occurred before, too, as SpaceX dumped $2 billion into xAI last July.

He’s also said on several occasions that he could eventually bring everything together into some sort of single entity. In July 2024, he said:

“I’m not opposed to the idea in principle, but I’m not sure there is a pragmatic or legal way to merge them. There is also value in equity incentives of people at the companies being tied to that company’s accomplishments.”

This point is especially relevant now with Musk’s recently approved compensation package.

He also said in June, during an interview with CNBC , that “It’s not out of the question” for xAI to merge with Tesla, but it would have to be approved by shareholders. Just a few days later, he said he would not support xAI merging with Tesla; however, he put it in investors’ hands.

It’s more than just a deal; it’s symbiotic. Musk being at the helm of various companies, all intertwined with one another, helps foster recursive innovation. Despite these advantages, there are still a handful of things to consider, especially from a regulatory perspective.

However, it is not competition; it’s convergence. In Musk’s universe, especially from a business sense, mergers are not endpoints, but instead launchpads for ambitions that aim to take each company from Earth to lands beyond our atmosphere.