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Drilling down

How optimizing mineral discovery can enable an electrified future.

It’s a telltale sign that you might be a rock hound: You keep minerals on your desk—and you know the chemical formula for them.

“That is chalcopyrite, C-U-F-E-S-2,” says Tyler Hall, PhD ’23, co-founder and president of the venture ExploreTech, holding up a brassy stone that sparkles in the light. “It’s also my license plate.”

Not to be outdone, his co-founder and CEO Alex Miltenberger, PhD ’22, lifts a wavy piece of native copper that reminds him of the upper peninsula of Michigan, his home state. “You can just find it in driveways because the gravel is left over from old mines,” he says.

While mining has long been a gamble, these co-founders hope to improve the odds for discovery.

Earth scientists typically use a combination of field reconnaissance, surveying, and geochemical analysis to figure out where to dig. It’s like searching for a needle in a haystack that can be thousands of meters deep.

Yet recent advances in artificial intelligence are enabling better modeling, which leads to better guesses. The ExploreTech team has devised technology that uses AI-informed simulation and drill planning to streamline and stack the deck in favor of geologists. 

“With our technology, fewer boreholes are drilled, which means there’s faster discovery, less land disturbance—and fewer ecosystems disrupted,” says Hall, pointing to one client case study where their methods achieved the same effectiveness as industry-standard drilling, with 85 percent fewer boreholes. That translates into significant cost savings, given that each borehole costs $50,000 to $200,000, on average.

Their process is faster too—a lot faster. ExploreTech has designed a cloud-based system that lets geologists visualize and test their theories about what’s below the Earth’s surface, shrinking the planning process for mineral discovery from months, or even years, to mere days.

Rock solid

In 2017, the co-founders met within their first weeks at Stanford and quickly connected over a mutual interest in mining. 

Tyler Hall, PhD '23

“I hear it from friends sometimes: ‘Oh, you’re working in mining. Isn’t that bad for the environment?’” says Miltenberger, who as a pragmatist, points to how the very technologies driving an electrified future require rechargeable batteries, which in turn depend on mining.

“Our whole built world comes from materials in the subsurface,” he says. “It’s our job as people in the profession to do it sustainably. We need to discover more minerals and metals because unless we do, the energy transition is going to be expensive and out of reach.”

Alex Miltenberger, PhD ’22

 As the global demand for lithium-ion batteries is expected to increase more than five-fold by 2030, the ExploreTech team sees their technology as a means to meet these future demands. With more consumers switching to electric vehicles and energy storage systems, there will be a tandem demand for critical battery minerals, such as lithium, cobalt, graphite, nickel, and manganese.

“What is discovered using our platform will supply that energy transition,” Hall says.

They say the TomKat Center for Sustainable Energy has been a key ally.

ExploreTech uses geospatial data and proprietary algorithms to develop mineral exploration plans that increase yields, reduce costs, and minimize environmental disruption. Image: courtesy of ExploreTech

In 2021, Hall became a TomKat Graduate Fellow for Translational Research, allowing him to develop AI planning methods for subsurface exploration, along with his advisor Professor Jef Caers. Meanwhile Miltenberger wrapped up his PhD on probabilistic inverse theory in geophysics under the mentorship of Professor Tapan Mukerji.

“You can think of it like a metal detector,” Miltenberger says, explaining his doctorate. “All you can hear is the metal detector’s beep, and your job is now to figure out what does that beep mean. Is that gold? Is it a tin can?”

“And so that’s essentially what probabilistic inverse theory does: It says, ok, 50 percent chance of gold, 50 percent chance of tin can—or ideally 80 or 90 percent chance of gold. It’s a way of putting numbers on what those indirect measurements of the subsurface mean.”

And here is where the co-founders’ research dovetails.

“What Tyler does with that information is he runs decision theory that says: If I know it’s 50 percent chance of gold, how much money and time should I sink into this exploration target before calling it quits?”

So in 2022, they secured an Innovation Transfer Grant to offset the cost of cloud computing needed to build out their technology, as well as to secure early customers and pitch at a major mineral exploration conference in Vancouver, B.C.

“A lot of our progress is because of TomKat,” says Miltenberger.

Big league

Creating jobs is on the co-founders’ minds too. For four years, Hall lived in a 2,000-person copper-mining town, where he coached Little League in the evenings while working at Freeport-McMoRan’s Bagdad Mine.

“That’s Arizona, not Iraq,” he says. “Best people I’ve ever met.”

His hope is that their software can give the smaller miners a bigger shot.

“If companies don’t drill the right drillholes, or in the right order, they could miss a discovery,” he says of the mineral exploration that precedes mining. “Well-planned drilling can make or break a project, and a discovery will significantly benefit the local economy.”

Reyna Silver is a mineral exploration company that used ExploreTech’s platform to locate an unusual magnetic region beneath volcanic rock in property they own in Chihuahua, Mexico, indicating the possibility of ore. ExploreTech was able to project thousands of possible 3D subsurface orebody models to pinpoint the best drilling plan before the company ever broke ground.

By locating raw materials more precisely, the co-founders want to bolster mining communities, while also limiting the harm in the hunt for these precious metals.

“By taking this company big league, we can have a significant impact on making sure that good technology is scaled as widely as it can be,” says Hall.

Miltenberger nods. “We’re not going to stop until these tools are integrated into every toolbox out there, so every geoscientist can make use of them.”

This article is part of the TomKat Center Spotlight series designed to highlight the impact and trajectory of the work of faculty and students who received funding through our Innovation Transfer Program, TomKat Solutions, and Graduate Fellowships. Stanford University does not endorse any non-Stanford entities, programs, products, or services listed in the article.