'It's had 1.1 billion years to accumulate': Helium reservoir in Minnesota has 'mind-bogglingly large' concentrations

A recently discovered helium reservoir in Minnesota boasts "mind-bogglingly" high concentrations of the gas that are even greater than initially thought, potentially paving the way for commercial extraction.

Resource exploration company Pulsar Helium, Inc. announced the discovery of helium stores in late February, after a drill just outside of Babbitt, in northern Minnesota, located gas deposits at depths of 2,200 feet (670 meters). Initial measurements showed helium concentrations of 12.4% — which "is just a dream," Thomas Abraham-James, the president and CEO of Pulsar Helium, told CBS News at the time. But new laboratory readings have surpassed those results.

The new tests reveal helium concentrations up to 13.8%, which are the highest the industry has ever seen, according to a statement. "That's just a mind-bogglingly large number, because really anything that's 0.3% or 0.5% helium or greater is of interest," Abraham-James told Live Science. 

Despite being the second-most abundant gas in the universe, helium is scarce on Earth and only forms through nuclear fusion or the radioactive decay of uranium and thorium. 

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Normally, helium is obtained as a byproduct of natural gas production, as it accumulates underground in pockets of methane and other hydrocarbons. Minnesota is one of just a handful of locations globally where helium is known to exist without hydrocarbons — the others being in Greenland and southern and eastern Africa. These sites all feature a crust of granite rock rich in uranium and thorium, as well as a rift system that fractures the rock to expose the helium produced through radioactive decay. A dose of volcanism then releases helium atoms from the rock.

"The last ingredient that you need is somewhere for that all to be trapped, and so that could be a sedimentary basin or, like for our project, an igneous rock," Abraham-James said. "For us, it's had 1.1 billion years to accumulate in there, which may account for why the concentration is so high."