“You’ve got a great boss,” Mitt Romney proclaimed to a crowd of coal miners at a campaign rally in August.

He was referring to Robert Murray, the CEO of Murray Energy, one of the largest coal mining operators in the country.

For Romney, that statement was particularly true. According to accounts from multiple coal miners, employees were forced to attend the event without pay. “Just for the record, if we did not go, we knew what would happen,” said one miner in a letter to a local radio station. Weeks later, Romney’s campaign featured images of the coal miners in a pro-coal ad. (The Obama campaign hit back this week with an ad claiming Romney used coal workers as “props”).

But that was just the tip of the iceberg. An expose from New Republic Senior Editor Alec MacGillis shows that Murray Energy is doing far more than requiring employees to spend uncompensated time at campaign events — the company is actually requiring them to donate to GOP candidates like Romney:

The accounts of two sources who have worked in managerial positions at the firm, and a review of letters and memos to Murray employees, suggest that coercion may also explain Murray staffers’ financial support for Romney. Murray, it turns out, has for years pressured salaried employees to give to the Murray Energy political action committee (PAC) and to Republican candidates chosen by the company. Internal documents show that company officials track who is and is not giving. The sources say that those who do not give are at risk of being demoted or missing out on bonuses, claims Murray denies. The Murray sources, who requested anonymity for fear of retribution, came forward separately. But they painted similar pictures of the fund-raising operation. “There’s a lot of coercion,” says one of them. “I just wanted to work, but you feel this constant pressure that, if you don’t contribute, your job’s at stake. You’re compelled to do this whether you want to or not.” Says the second: “They will give you a call if you’re not giving. . . . It’s expected you give Mr. Murray what he asks for.”

This spring, Murray organized a fundraiser for Mitt Romney, eventually bundling more than a million and half dollars for the candidate. According to the New Republic, employees of Murray Energy have donated more than $1.4 million to Republican candidates — with $120,000 raised for Romney this campaign season alone.

While employees say Murray does not explicitly force them to make donations, he makes it very clear what could happen if they don’t contribute some of their salary to Republicans. “We have been insulted by every salaried employee who does not support our efforts,” he wrote in one 2012 letter obtained by the New Republic.

And in a 2011 letter to company managers, Murray alluded to potential consequences if employees did not donate: “Please see that our salaried employees ‘step up,’ for their own sakes and those of their employees.”

Other national candidates supported by the “coerced” donations of coal workers include House Speaker John Boehner, Scott Brown, Rand Paul, David Vitter, and Congress’ most aggressive climate denier, Jim Inhofe. “Hopefully you will support every one of these friends of coal,” wrote Murray to his employees.

Murray, who is a fierce defender of the coal industry, is also a fierce climate denier. He has called climate change a “theory” and has blamed climate scientists for supposedly “perpetuating fraud.”

As governor of Massachusetts, Mitt Romney once proclaimed that coal plants “kill people” and established a “no regrets” plan to combat global warming. Today, with massive financial backing from the fossil fuel industry, Romney says that “we don’t know” what’s causing global warming. And in the presidential debate this week, he proclaimed “I like coal.”

Now we know why.