The U.S. is running out of miners. More than half the nation's mining workforce, about 221,000 workers, is expected to retire by 2029, according to the Society for Mining, Metallurgy & Exploration, and the number of candidates willing to fill those slots is shrinking.
"Our workforce is aging," said Bold Baatar, chief executive of copper at Rio Tinto. "There is a lot of baby boomers that will be looking to retire or are already retiring, and we're continuing to rely on their expertise."
At the same time, demand for rare earth minerals such as lithium, cobalt and copper, critical components used to make batteries for electric vehicles and smartphones, is on the rise.
Globally, at least 384 new mines will need to be built to meet demand for electric vehicles by 2035, according to Benchmark Mineral Intelligence.
To better understand the role miners play in the transition to green energy, CNBC got a behind-the-scenes look at Rio Tinto's copper mining operation in Utah.