While on the campaign trail in West Virginia last year, Donald Trump donned a hardhat and pantomimed digging coal with a shovel. The coal miners in the audience would soon be back to work, he promised: “Get ready, because you are going to be working your asses off.”

The only problem: Coal miners no longer swing a pickax or wield a shovel. While coal companies are hiring again, executives are starting to search for workers who can crunch gigabytes of data or use a joystick to maneuver mining vehicles hundreds of miles away.

“If you do PlayStation, you can run...