The writing has been on the wall as domestic and global coal markets have evaporated, but the announcement last week by St. Louis-based Arch Coal still came with a loud thud. Arch, the second largest U.S. coal producer, now in bankruptcy, announced it would no longer seek a permit for the largest proposed coal mine in the country, in Montana's Otter Creek Valley.

The company cited "further deterioration in coal markets" in its decision to table its application to the Montana Department of Environmental Quality for a mine in southeastern Montana's portion of the Powder River Basin that contains 1.4 billion tons of coal.

But while opponents of the mine celebrate, the coal leases have not been cancelled by Arch, so those leases, valid through 2022, can be sold. Considering current market and regulatory trends, though, it seems unlikely another company would invest in them.

The Montana Land Board had leased the Otter Creek coal tracts to Arch for $86 million in 2010, which coincided with the beginning of a precipitous drop in natural gas prices. Arch and other coal companies saw the looming shifts in domestic electricity generation, but planned an end run by exporting coal to booming markets in Asia.

In 2011, Arch partnered with BNSF Railway and billionaire candy bar mogul Forrest E. Mars, Jr., who owns property along the Tongue River, to acquire the Tongue River Railroad Company.

In 2012, Arch asked the DEQ to permit an open-pit mine, while the Tongue River Railroad Co. called for the Surface Transportation Board to green-light a rail spur, routed directly to the mine. The companies eyed a path to the handful of proposed coal-export terminals in the Pacific Northwest. Arch is a 38 percent shareholder in one of them, the Millennium Bulk Terminals project in Longview, Wash.

But since 2012, the coal export market has fizzled, too. China's coal imports fell 30 percent in 2015, the biggest drop on record. The price of Australian coal, the regional benchmark, has fallen to around $50 per metric ton, its lowest price in nearly a decade.

Matthew Korn, a Barclays analyst based in New York, recently described the export market as "dreadful." The U.S. can't compete with Russia, Australia and Indonesia, among other major coal-exporting countries, for the remaining demand.

Late last year, the Tongue River Railroad Co. asked the Surface Transportation Board to suspend its railroad application until the DEQ issued mining permits. Arch had already delayed that process by not paying the DEQ for its work.

The DEQ found Arch's mining and surface water discharge permit applications to be deficient, leaving the agency also waiting on the company to respond to many outstanding environmental concerns.

A DEQ spokesperson said Arch's application had effectively been suspended long before the company issued its news release last week.

Prior to its bankruptcy declaration in January, Arch Coal had seen it shares drop to less than $1 a share, disqualifying them from the New York Stock Exchange. Arch was allowed to rebundle and combine its shares 10-to-1 to raise its per-share value back to around $10 last fall. But its value fell below $1 again prior to Arch's bankruptcy filing.

Even though burning the valley's coal over the life of the mine would release an estimated 2.5 billion tons of carbon dioxide, the Montana Legislature, in 2011, restricted the DEQ from considering such "cumulative impacts." It did so by explicitly limiting the scope of the Montana Environmental Policy Act to "within the borders of Montana."

For now, at least as it pertains to the proposed Otter Creek mine, that change in law is moot.

Montana politicians, however, seem to disregard the market factors and pin blame for the coal industry's struggles elsewhere. Republican U.S. Sen. Steve Daines called the permit suspension, "a devastating loss" for the state's economy. "This decision is an unfortunate repercussion of President Obama's all-fronts assault on domestic energy production," he said.

Korn, the Barclays analyst, estimates that two-thirds of the coal industry's struggles can be attributed to cheap natural gas, which he calls "a success of American industry that has now led to massive, massive changes in geopolitics."

As the Tongue River Railroad Co. itself stated in a Surface Transportation Board filing in 2012: "Indeed, the market is the best governor of the demand for a new rail line and here market forces are coalescing behind a determination that the coal resource at Otter Creek should be developed and transported."

Market forces are coalescing behind quite a different determination today.

"Montana has a long history with mining companies walking away," said Kate French, chair of the non-profit Northern Plains Resource Council, which has opposed both the mine and railroad. "We should count our lucky stars that Arch Coal walked away before this project was built, and before it wrecked the Otter Creek valley."