JUDY WOODRUFF:

President Trump has pledged to revive the coal industry, and has already begun rolling back some government regulations.

In one case, that means boosting so-called mountaintop mining. But even as many in coal country applaud those moves, there's concern over what it means for the environment.

That is the focus of this week's report from Miles O'Brien.

It's part of our weekly series on the Leading Edge of science and technology.