KAIBAB NATIONAL FOREST>> More than 1,400 feet below an Arizona pine forest, miners are blasting tunnels in search of a radioactive element that can be used to make electricity.

Two states north, in central Wyoming, drillers have been digging well after well in the desert, where that element — uranium — is buried in layers of sandstone.

Uranium mines are ramping up across the West, spurred by rising demand for electricity and federal efforts to cut Russia out of the supply chain for U.S. nuclear fuel.

Those twin pressures have helped lift uranium prices to their highest levels in more than 15 years, according to the consulting firm TradeTech, helping to resuscitate mining regions that entered a steep decline toward the end of the Cold War.

Nuclear power is coming back into vogue in the United States as politicians and investors embrace the technology as a way to meet growing energy demand without releasing the gases responsible for climate change. Microsoft, which is building energy-hungry data centers, recently said it would pay an energy company to reopen the Three Mile Island nuclear power plant in Pennsylvania, closed since 2019.

Uranium is just one of the elements that corporations and government officials are seeking to produce domestically to help the country transition away from oil, gas and coal. Lithium and nickel are some of the others.

Whether the new generation of American uranium prospectors thrives or fails will largely depend on how long that momentum lasts — and whether prices remain high enough to encourage companies to dust off old mines.

“I liken it to a broken arm that’s been in a cast for a long time,” said John W. Cash, chief executive of Ur-Energy, a mining firm that is ramping up uranium production in central Wyoming. “The muscle atrophies, and that’s where our industry is.”

While some communities have welcomed the new investment, others — particularly in Arizona — are pushing back over concerns about the potential health and environmental consequences of harvesting radioactive materials near homes and livestock.

“We’re already contaminated here in the Southwest,” said Carletta Tilousi, a member of the Havasupai, a tribe that recognizes land near a uranium mine in Kaibab National Forest as sacred. “This is our homeland.”

Workers began extracting uranium from that mine, Pinyon Plain, late last year. Owned and operated by a company called Energy Fuels, the facility is composed of a web of damp, 10-foot-by-10-foot tunnels that are a five-minute elevator ride below the ground. Miners with hand-held jackleg drills and explosives remove dark gray chunks of uranium-rich ore from the earth.

Back above ground, that rock is trucked some 260 miles northeast to the White Mesa uranium mill in Utah, where workers turn it into a bright powder known as yellowcake. That concentrated form of uranium is then further processed, enriched and turned into fuel for nuclear power plants.

In 1980, the United States produced nearly 44 million pounds of yellowcake, federal data show, enough to feed most domestic nuclear reactors today.

But nuclear power fell out of favor after accidents that included a cooling failure at Three Mile Island in 1979 and an explosion at the Soviet Union’s Chernobyl plant in 1986. After the breakup of the Soviet Union in 1991, Russia agreed to dilute weapons-grade uranium for use in U.S. reactors, flooding the market.

Last year, the U.S. produced just 50,000 pounds of yellowcake. The rest was harvested in mines from Canada to Kazakhstan, and enriched in several countries, including Russia.

The U.S. is now seeking to reduce its dependence on Russia after the country invaded Ukraine in 2022. A law that went into effect this year will block U.S. power plants from buying Russian uranium by 2028. Roughly a quarter of the enriched uranium used in U.S. nuclear reactors comes from Russia, federal data shows.

Consultants expect domestic mining activity to rebound relatively quickly, with U.S. production reaching roughly 6 million pounds of yellowcake around 2028.

But people who live near uranium mines, including Indigenous tribes, fear such a quick rebound.

Much of the activity during the last American uranium boom of the 1950s through the 1980s happened on or near Native lands. When prices collapsed, companies abandoned hundreds of mines. Scores of those sites have yet to be cleaned up, leaving residents exposed to elevated levels of radiation, which can increase the risk of developing lung and bone cancer and other diseases.

Signs put up on Navajo land along Energy Fuels’ transportation route in Arizona by the Environmental Protection Agency warn people against “Building, Gathering, Playing, Corrals, Digging.” The agency has been working with the Navajo Nation and mining companies to assess and clean up contamination.

This summer, members of the Navajo and Havasupai tribes were among those who staged protests seeking to block Energy Fuels from trucking ore through Navajo land. Energy Fuels voluntarily suspended uranium transportation in August and said it was working with the tribes.

Mable Franklin, 66, was among the Navajos who protested. Referring to the abandonment of mines in the area, she said, “It’s just something that shouldn’t have happened.”

Environmental regulations and radiation safety have improved over the past half-century, in part because of the Federal Mine Safety and Health Act. Companies operating today, including Energy Fuels, are required to monitor radiation levels in the soil and water around their sites, as well as post bonds to cover cleanup costs.

Tribal communities are particularly concerned about their groundwater. In the tunnels at Pinyon Plain, water levels can be at the midpoint of an adult’s calf muscle from moisture in the rock.

But a former Arizona regulator who was charged with approving state permits, Misael Cabrera, said the mine does not pierce underground barriers to the major aquifer that supplies drinking water throughout the state.

Cabrera, a former director of the state’s Department of Environmental Quality, said Pinyon Plain was “the most stringently regulated facility in the state of Arizona.”

In an Aug. 13 letter to the U.S. Department of Agriculture, Arizona’s attorney general requested a supplemental environmental impact study related to surrounding aquifers. The letter followed an Energy Fuels report to state regulators about elevated levels of heavy metals in water pumped from the mine in 2023. The company said that the pumped water is placed in a pond designed to protect the surrounding area.

Miners today are exposed to far less radiation on the job than they were in the 1970s. Risks differ, though, depending on the type of mine. Underground mines can be hazardous for workers if poorly ventilated.

Energy Fuels said it did not operate and abandon mines on Navajo land. The company, which is based in Lakewood, said it pumped fresh air underground through enormous ducts to help clear harmful gases such as carbon monoxide and radon.

In an interview, the company’s chief executive, Mark Chalmers, said he knew well the toll that uranium mining had taken on Native American communities. The owner of the first mine where Chalmers worked was dying of cancer from inhaling toxic air in a uranium mine when he gave Chalmers part ownership of the operation, with a warning: “Don’t be stupid like I am.”

Because of that experience, Chalmers said, he has made sure his mines are properly ventilated. Energy Fuels said it also protected neighboring communities by controlling dust, monitoring radiation levels and cleaning up sites.

Even so, many tribal communities filed lawsuits that blocked Pinyon Plain’s mining operations for a time. The tribes claimed that the company was mining on sacred ground. Eventually, the courts determined that the operation could proceed, and Arizona regulators approved permits in 2022, Cabrera said.

In Wyoming, Ur-Energy’s Lost Creek mine is some 15 miles from the nearest town, Bairoil, home to fewer than 100 people. The company’s extraction process is akin to the techniques used to produce oil and gas. Rather than removing chunks of rock from the earth, the company is drilling hundreds of small wells in the desert, then sending groundwater mixed with oxygen and carbon dioxide into the uranium-rich sandstone below.

Some 450 feet beneath the surface, uranium dissolves into that fluid, and Ur-Energy pumps it back up. Nearby, the company sends the solution through a series of tanks and a vacuum dryer, processing it into yellowcake. The water is reused to extract more uranium.