President Donald Trump appeared alongside lawmakers and coal miners Thursday, officially undoing an Obama administration regulation that he called a "job-killer."

Trump said that scrapping the rule - put in place in December to protect waterways from coal mining waste - would save "many thousands [of] American jobs, especially in the mines."

At the signing ceremony, Trump was flanked by Senate Majority Leader Mitch McConnell (R-KY), Sen. Rand Paul (R-KY), Sen. Joe Manchin (D-WV) and Sen. Shelley Moore Capito (R-WV).

He was also joined by a group of miners, including Mike Nelson, superintendent of the Marion County Coal Company in West Virginia. Nelson was called up to the podium unexpectedly to make a few remarks.

Nelson joined "Fox & Friends" today, saying he believes Trump's plans will "help turn this industry around" after a "down period" under the Obama administration.

"I’ve been in this industry 40 years. ... I’m excited for the people who work in this industry," he said.

Nelson said coal miners have been promised jobs "for the longest time," and it hasn't happened.

"For a politician, such as Donald Trump, to step up and hold good to his promise, is absolutely fantastic. He’s an inspiration to all working Americans," said Nelson.

Environmental groups, like Greenpeace USA, urged supporters to take notice, warning about the potentially-damaging impact.

Trump just killed a rule restricting coal companies from dumping waste in streams. It's time to resist! #ResistOften https://t.co/17heR3KtMf pic.twitter.com/EQ6olpEzX2 — Greenpeace USA (@greenpeaceusa) February 17, 2017

Nelson said many of the critics don't understand the coal industry and the environmental concerns are overblown.

"We are deep mines and we don't hurt the environment at all," he said.

Watch the interview above.

'Very Fake News': Pres. Trump Questioned on Intel Leaks by CNN's Acosta

Hannity: Trump Gave Media a 'Historic Beatdown' at Press Conference

Campos-Duffy: 'People Trust Donald Trump More Than They Trust the Media'