The Chapter 11 filing didn't come as a surprise. The company failed to make payments earlier this month, and CEO Robert Murray had been warning about the difficulties facing coal companies.

The company, which was the largest privately held coal company in the country, on Tuesday announced that it had entered into a restructuring agreement with its lenders .

Murray Energy is the latest casualty in the coal industry as consumers shift to cheaper and cleaner sources of power.

Robert Murray began working in coal mines at 16. He went on to found the St. Clairsville, Ohio-based company in 1988 and grew the company through a series of acquisitions.

At least seven coal companies have filed for bankruptcy protection this year, and dozens of coal plants have closed over the last few years. The waning demand for coal comes as consumers shift to cleaner and cheaper sources of power such as natural gas and renewables.

Last year, demand for coal fell to its lowest level in 40 years, according to the US Energy Information Administration, with coal production dropping to its second lowest level since 1978.

Robert Murray is a vocal and financial supporter of President Donald Trump. He advised the president on issues related to the coal industry, and was present in 2017 when Trump signed a measure rolling back an Obama-era regulation that prohibited coal mining near waterways.

At a campaign rally in West Virginia last year Trump declared that "the coal industry is back." But more than 50 coal plants have closed since the 2016 election. And this past April, for the first time ever, renewable energy sources like solar and wind farms provided more of the US' electricity than coal, according to the U.S. Energy Information Administration.

Murray has made his opinions on energy regulation widely known, with some even saying he had too much control over the president. In 2018 The New York Times published a story on Murray's influence over Trump's energy policy.

The report resurfaced accusations by environmental groups that Murray hand-delivered the coal and nuclear subsidy proposal to Perry. Murray denied these claims.

Murray is a known critic of climate change. In 2017 he told CNBC that global warming is a "hoax," claiming that 4,000 scientists told him so.

In another CNBC interview, he called Tesla a "fraud," saying it "has gotten $2 billion from the taxpayer," and "has not made a penny yet in cash flow."