The way Donald Trump talks about the coal industry, Appalachian miners will be getting back to work on day one of his administration. “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,” the presumptive Republican nominee said earlier this month. Everything will be great.

What is unclear is how Trump intends to make coal mining great again, since he doesn’t appear to understand the first thing about the industry he intends to save — neither the broad-brush economics, nor what is within the president’s power to do. Even a coal industry executive, Bob Murray, CEO of Murray Energy and vocal Obama critic, has to admit Trump doesn’t know what he’s talking about.

In an interview with Taylor Kuykendall, a reporter for the trade publication SNL Energy, Murray revealed just how little Trump really gets about coal.

Trump, for instance, reportedly asked Murray, “What’s LNG?” (It stands for liquified natural gas, which the candidate might want to read up on as the glut of cheap natural gas is a large factor in coal’s demise.)

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Murray also told Kuykendall that Trump is over-promising and should stop setting unrealistic expectations for coal’s big comeback: “I don’t think it will be a thriving industry ever again,” Murray said. “We’ll hold our own. It will be an extremely competitive industry and it will be half size. … The coal mines can not come back to where they were or anywhere near it.”

Implicit in Murray’s comments is the fact that there is a lot outside a president’s control when it comes to coal. These include: sinking prices for natural gas and renewable energy that have made coal far less competitive; other markets’, like China’s, demand for coal; and coal production moving from Appalachia to Wyoming, now the top U.S. coal producer, where it’s cheaper to mine.

In other words, Trump can do his worst — like scrap the Environmental Protection Agency — and it won’t bring about an economic revolution for these states. Murray all but admits that when he says he’s skeptical of Trump’s abilities to reverse all these trends.

Trump’s delusions, however, won’t stop the industry from embracing him. Calling Trump “the horse to ride” in a speech yesterday, Murray was ready to give Trump a pass on the policy. As he told Kuykendall, “he’s just focused on getting elected so he has to kind of gloss over all of the issues.”

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Trump will be presumably be enlightening us on his energy policy on Thursday, in a speech in North Dakota, home of the domestic oil and gas boom that has helped kill coal.