AP FACT CHECK: Bringing coal jobs back to Appalachia
Trump, however, has yet to explain exactly how he will revitalize Appalachia's coal industry. To pull it off, he will have to overcome market forces and a push for cleaner fuels that have pummeled coal.
Coal's slump is largely the result of cheap natural gas, which now rivals coal as a fuel for generating electricity. Older coal-fired plants are being idled to meet clean-air standards.
Another hurdle for reviving coal mining in Appalachia: less coal. Reserves of coal still in the ground are smaller than in western states like Wyoming, the leading coal producer.
There is no question that there are fewer mining jobs today. According to the Labor Department, there were 56,700 jobs in coal mining in March, down from 68,000 just a year earlier. In March 2009, shortly after President Barack Obama entered office, there were 84,600 coal-mining jobs.
TRUMP: "We're going to get those miners back to work ... the miners of West Virginia and Pennsylvania, which was so great to me last week, Ohio and all over are going to start to work again, believe me. They are going to be proud again to be miners."
THE FACTS: It is unclear what Trump would do to increase mining jobs. He has long criticized the Obama administration's Environmental Protection Agency, saying that its proposals to tighten emission standards on coal-burning power plants are killing American jobs. A Trump adviser said that a Trump administration would review many EPA regulations including those affecting the coal industry.
While the requirements have raised the cost of operating coal-fired plants, experts say a bigger factor in coal's decline has been cheaper natural gas. Drilling techniques such as fracking have sparked a boom in gas production, driving down prices and prompting utilities to switch from coal.
As recently as 2008, about half the electricity in the U.S. came from burning coal and one-fifth from burning natural gas. Today, each accounts for about one-third — nuclear, hydroelectric and renewables like solar and wind make up most of the rest. Weak economic growth has hurt demand for Appalachian coal used in making steel.
U.S. coal production fell 10 percent last year. The Energy Department predicts it will drop 16 percent this year, the biggest one-year decline since 1958.
John Deskins, director of an economic-research bureau at West Virginia University, said government's ability to boost coal production is limited.
"It is very unlikely we will see a return to levels of coal production like we observed in 2008," the most recent peak in the state, Deskins said. Easing EPA restrictions — the industry is challenging EPA in court — would help over the long run, but not enough to offset the loss of market share to natural gas, he said.
There is another limitation on coal's future in Appalachia: After decades of heavy production, there is less of it to be mined.
Wyoming, with rich reserves of low-sulfur coal near the surface, is the largest coal-producing-state and has the most coal still in the ground at producing mines. According to the U.S. Energy Information Administration, Wyoming has three times as much recoverable reserves at producing mines as West Virginia and about twice as much as West Virginia, Pennsylvania and Ohio combined.
TRUMP: "I want clean coal, and we're going to have clean coal and we're going to have plenty of it. We're going to have great, clean coal. We're going to have an amazing mining business."
THE FACTS: Clean coal covers a range of technologies, some already in use, to reduce pollution. Many types of emissions from coal-fired plants have been reduced, but the capturing and storing of carbon dioxide, the emission that scientists say is most responsible for climate change, has been harder to accomplish on a significant scale.
A model carbon-capture plant being built in Mississippi has encountered repeated delays and huge cost overruns that will make it one of the most expensive power plants ever built. The coal industry complains that carbon capture has not received the government incentives showered on renewable energy.
TRUMP: "We're not going to be Hillary Clinton. I watched her three or four weeks ago when she was talking about the miners as if they were just numbers, and she was talking about she wants the mines closed and she will never let them work again."
THE FACTS: Trump is hitting Clinton for comments she made in March on CNN and which continue to dog the presumptive Democratic nominee on the campaign trail. But the remark was part of a longer answer.
Clinton said she had a policy to help coal country benefit from creating renewable energy "because we're going to put a lot of coal miners and coal companies out of business, right?" That was quickly followed by "We've got to move away from coal and all the other fossil fuels, but I don't want to move away from the people who did the best they could to produce the energy that we relied on."
This week an out-of-work coal miner in West Virginia confronted Clinton about the remarks, even handing her a photo of his family. Clinton said she had made "a misstatement."
"What I was saying," she told the voter, "is that the way things are going now we will continue to lose jobs."