A mining company asked the U.S. Supreme Court to weigh in on Virginia’s ban on uranium mines. (Jim Watson/Agence France-Presse/Getty Images)

The U.S. Supreme Court agreed on Monday to consider whether Virginia has the right to ban a uranium mine, reviving discussion about a deposit on the state’s southern border that’s said to be the nation’s richest source of the mineral used in nuclear reactors.

The massive uranium deposit in Pittsylvania County, at the midpoint of the state’s border with North Carolina, was discovered decades ago, but in the 1980s the General Assembly prohibited mining because of concerns about radioactivity.

There have been several efforts to study the safety of digging out the ore, but lawmakers have kept the ban in place for more than 30 years. Former governor Terry McAuliffe (D) announced shortly after being elected in 2013 that he would veto any legislation that sought to permit uranium mining. Since then, the company interested in opening a mine has given up on legislation and taken its case to the legal system.

“Obviously, they’re thrilled that the court is going to hear the case,” Julie Rautio, a spokeswoman for Virginia Uranium in Chatham, said Monday.

Lower courts have ruled against Virginia Uranium and in favor of the state’s ban. But the company asked the Supreme Court to review a split decision issued last year by the U.S. Court of Appeals for the 4th Circuit.

That request got a boost last month when the U.S. solicitor general weighed in on behalf of the Nuclear Regulatory Commission and supported the company’s call for the high court to take up the case.

The federal government argued that the state has no jurisdiction to prohibit the mine, because such activities are regulated by the NRC. The Atomic Energy Act gives the federal commission the power to oversee all matters of radiological safety, the government argued, so the state cannot ban mining over its fear of radiation hazards.

Allowing Virginia to have such power “creates a division of authority over an issue of profound national importance — the basic allocation of regulatory power over atomic energy and radiological safety and access to a strategically critical national resource,” the solicitor general argued in a brief with the court.

But Virginia has maintained that it does have jurisdiction and that the Atomic Energy Act is aimed at uranium mining on federal lands. The Pittsylvania deposit, near Chatham, is privately owned and so outside federal jurisdiction, Virginia Attorney General Mark R. Herring has argued.

“Federal law does not override the decision the Commonwealth made after weighing the significant risks of an unprecedented uranium mining operation,” Herring said via email. “My team and I have successfully defended the moratorium at trial and on appeal, and we are confident we can do so again at the Supreme Court.”

A spokesman for Gov. Ralph Northam (D) said he, like his predecessor, “strongly supports Virginia’s ban on uranium mining. He believes the proposed projects to mine uranium in Virginia pose unnecessary risks to families and businesses, and he looks forward to seeing the ban upheld in court.”

The conflict sets up a test of states’ rights under the Trump administration that caught at least one legal scholar by surprise.

“It’s a bit of a different juxtaposition from what you might expect from a Republican administration,” University of Richmond law professor Carl Tobias said. “If the administration really cares about federalism and states’ rights, it shouldn’t be weighing in in this way.”

At stake is a uranium deposit estimated at 119 million pounds — the richest known deposit in the United States and among the biggest worldwide. A few years ago, the haul was said to be worth $10 billion, although the price of uranium has declined since the Fukushima reactor disaster in Japan in 2011.

Much of the deposit is controlled by the Coles family, which has owned the property for seven generations.

The Supreme Court will hear the case in its October term.