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.

MILES O’BRIEN: Rocky Hackworth is a coal miner who makes a surprising claim.

ROCKY HACKWORTH, Surface Mine Manager: I’m a true environmentalist. I work in it and live in it.

MILES O’BRIEN: And he reshapes it. He manages the 1,600-acre, Four Mile Fork surface mine 30 miles south of Charleston, West Virginia.

This is a state where the thick, deep layers, or seams, of coal are all but gone after 200 years of relentless underground mining.

ROCKY HACKWORTH: Now, you got a lot more of the smaller, thinner seams that are on top of these mountains. Those areas have already been mined out. So, the surface mine was just a natural progression.

MILES O’BRIEN: With a mother lode of unnatural consequences. In the hills of West Virginia, surface mining carries a huge cost, nothing less than the mountains themselves, the icons of this beautiful state.

CLAY MULLINS, Former Coal Miner: They had everything here. They had two or three post offices, I think.

MILES O’BRIEN: Clay Mullins is a former underground miner who lives near a mountaintop removal mine in Pax. He endures the sound of daily explosions and the destruction of woods where he once hunted and fished.

CLAY MULLINS: I think West Virginians are sacrificing too much of our mountains, our wildlife. Our wildlife really suffers. I just don’t like looking out and seeing the mountains get torn out the way they are.

MILES O’BRIEN: Ten percent of the land in Central Appalachia is now either active or reclaimed surface mines.

EMILY BERNHARDT, Duke University: The Central Appalachian landscape has been fundamentally changed, and it’s been changed in a way that it’s not going to recover from. Those mountains are not going to grow back.

MILES O’BRIEN: Emily Bernhardt is a professor of biogeochemistry at Duke University. She’s been researching the decapitation of mountains for seven years, trying to understand how it affects the rivers and streams below.

EMILY BERNHARDT: The problem is that for every about a meter of coal, you have about 99 meters of rock that you have to put somewhere during this process. And when you’re in a landscape like Appalachia, the place that most of that rock ends up being put is in river valleys.

MILES O’BRIEN: When the rock is pulverized in the mining process, toxic chemicals and minerals locked inside for millennia are released and exposed to the air, creating two areas of concern.

EMILY BERNHARDT: One, that the water coming out of these mines is salty, it’s full of rock-derived salts, and that by itself is stressful to many freshwater organisms. And the sort of subsidiary problem is that that salt contains lots of elevated levels of trace metals, which have known toxicity to organisms.

MILES O’BRIEN: But the mining industry believes that concern is overstated.

ROCKY HACKWORTH: This is a good example of a ditch that we have to build on top of a valley field.

MILES O’BRIEN: Rocky Hackworth showed me the trenches and retention ponds designed to capture run-off and protect the surrounding environment.

ROCKY HACKWORTH: That way, you don’t have anything that is leaving the property. Downstream, there’s no consequences. We have had samples taken now for eight years, and we have never had a water issue.

MILES O’BRIEN: The coal industry says it tests water continuously.

Chris Hamilton is the senior vice president of the West Virginia Coal Association.

CHRIS HAMILTON, West Virginia Coal Association: It’s not something that’s done haphazardously. There’s a very, very high premium placed on that, and it’s a very important aspect, just like personal and individual mine health and safety.

MILES O’BRIEN: But the data tells a different story.

We joined Emily Bernhardt’s colleague Eric Moore, as he did some fieldwork near the largest surface mine in Central Appalachia. Active for more than 40 years, the Hobet mine has transformed about 10,000 acres of natural mountain peaks into manmade mesas.

The Duke team presides over 14 different monitoring sites in what appear to be clean mountain streams. They measure temperature, oxygen levels and acidity, and they also test the conductivity of the water, a good indication of the health of the stream.

In this case, the number is more than 1,900 microsiemens per centimeter.

What does that mean?

ERIC MOORE, Duke University: Well, compared to our natural watersheds, they run around 150.

MILES O’BRIEN: In this mountain stream, the conductivity is similar to an urban waterway filled with road salt and other pollutants. The only possible source here, the chemicals unleashed when the mountaintops are destroyed.

This is not a healthy stream?

ERIC MOORE: Correct, not at all.

MILES O’BRIEN: It looks good.

ERIC MOORE: Yes, looks fine.

MILES O’BRIEN: But it’s not.

ERIC MOORE: No, not at all.

MILES O’BRIEN: In the final days of the Obama administration, the federal Office of Surface Mining Reclamation and Enforcement published a new rule designed to protect streams like this. It would have prevented mining companies from impacting the hydrologic balance, forced them to monitor the water during mining, and mandated streams be restored to their natural state after the mining was over.

CHRIS HAMILTON: We saw signs of every agency that had any responsibility over mining proposed onerous rule after onerous rule, which really served to restrict, if not close down, a number of mining operations here.

MILES O’BRIEN: But President Trump has made some big promises to help the coal mining industry.

PRESIDENT DONALD TRUMP: And, for those miners, get ready, because you are going to be working your asses off, all right?

(CHEERING AND APPLAUSE)

PRESIDENT DONALD TRUMP: Thank you, everybody. Thank you.

MILES O’BRIEN: In February, he signed legislation killing the stream protection rule. And the president is promising more regulatory relief to bring back mining jobs.

Are people optimistic now here in coal country in West Virginia?

ROCKY HACKWORTH: Very much optimistic, 100 percent. It changed the day after the election.

MILES O’BRIEN: But scientists believe surface mining is taking a big toll, not just to the mountains and streams, but also to the humans who live nearby.

MICHAEL HENDRYX, Indiana University: If you value public health, this form of destruction around people’s community should stop, and even if that means that the mining companies make less money or the coal stays on the ground forever.

MILES O’BRIEN: Michael Hendryx is a professor of applied health science at Indiana University. He has studied the health effects of mountaintop removal in West Virginia for 10 years.

He has documented high occurrences of heart, lung, kidney diseases and some forms of cancer among people who live near mines. But the mining industry is skeptical.

CHRIS HAMILTON: There’s a segment of our culture and society here that’s had some ill health and some health effects, and most of that has been attributed thus far to lifestyle, diet, smoking and things of that nature.

MILES O’BRIEN: So, Hendryx is launching a new study designed to factor out those other causes.

He and his team will collect detailed health data, along with environmental exposures to various toxins. Participants will receive passive air sampling devices inside and outside their homes, and, on their wrists, silicone wristbands absorb certain toxins.

MICHAEL HENDRYX: We’re trying now to try to make those connections more direct between environmental conditions in these communities and the exposures that individual people are facing, and the health consequences of those.

MILES O’BRIEN: The consequences to the landscape and the environment are more clear-cut. At Four Mile Fork and all other mines, federal regulations require them to sculpt and replant the land that is mined out.

ROCKY HACKWORTH: These mountains have natural resources that God put there, and they were put here for a reason, to be used, and we’re using them and putting them back in place.

MILES O’BRIEN: But people who live near a surface mine, like former miner Clay Mullins, say the landscape is forever altered.

CLAY MULLINS, Former Coal Miner: It all comes back to that almighty dollar, because that’s what they care about. And that’s what they’re in business for, is to make money.

Now, everybody understands that stuff, now, but you got to draw a line between what’s good for the health of your workers and what’s good for the health of the Earth.

MILES O’BRIEN: Wherever that line in the sand was before, the Trump administration is clearly determined to move mountains for the coal industry, even as it does the same in Central Appalachia.

In Kanawha County, West Virginia, I’m Miles O’Brien for the PBS NewsHour.

This article is reprinted with permission from PBS NewsHour. It was first published on May 3, 2017.