In Decatur, Ill., far from the coal mines of Appalachia, Caterpillar engineers are working on the future of mining: mammoth haul trucks that drive themselves.

The trucks have no drivers, not even remote operators. Instead, the 850,000-pound vehicles rely on self-driving technology, the latest in an increasingly autonomous line of trucks and drills that are removing some of the human element from digging for coal.

When President Trump moved on Tuesday to dismantle the Obama administration’s climate change efforts, he promised it would bring coal-mining jobs back to America. But the jobs he alluded to — hardy miners in mazelike tunnels with picks and shovels — have steadily become vestiges of the past.

Pressured by cheap and abundant natural gas, coal is in a precipitous decline, now making up just a third of electricity generation in the United States. Renewables are fast becoming competitive with coal on price. Electricity sales are trending downward, and coal exports are falling.