A disaster at a West Virginia coal mine with a history of violations killed two men who were engaged in "retreat mining," a process that an expert Tuesday called "the most dangerous type of [coal] mining you can do."

The West Virginia men -- Eric D. Legg, 48, of Twilight and Gary P. Hensley, 46, of Chapmanville -- died Monday night at Brody Mine No. 1 near Wharton in Boone County, about 50 miles south of the state capital of Charleston.

The fatalities mark the nation's fourth and fifth coal-mining deaths this year, according to the U.S. Mine Safety and Health Administration.

Federal and state inspectors were on scene at the mine, which is owned by Patriot Coal Co. in St. Louis.

The accident drew statements of sympathy from West Virginia Gov. Earl Ray Tomblin and his wife, Joanne, as well as from Mike Day, Patriot's executive vice president of operations.

The accident happened around 8:30 p.m. Monday, trapping the miners for a time before their bodies were recovered.

By Tuesday, it was still not entirely clear what happened. Patriot cited a "severe coal burst" during "retreat mining operations" as the cause. The mining administration said it was due to a "ground failure." And the West Virginia Office of Miners' Health, Safety and Training called it a "coal outburst."

Tony Oppegard, a former MSHA official and now a private lawyer in Kentucky who represents miners, said it sounded like an unexpected roof collapse might have occurred during the final phase of the operation.

In coal mining, when work is advancing, machinery makes wide tunnels and leaves pillars of coal holding up the roof.

During retreat mining, after miners have gone as far as they can, they work their way backwards, cutting the pillars, recovering the remaining coal, and intentionally causing the roof to collapse in front of them.

When engaging in retreat mining -- colloquially known as "pillar pulling" -- companies are supposed to file a detailed plan with MSHA before proceeding, Mr. Oppegard said. They are also expected to educate the miners who will be doing the work about the plan.

But, he said, "Usually when we have fatalities on pillar sections it's because the company was not following the pillar plan and/or the miners were not adequately trained in the pillar plan."

As each row of pillars is removed, additional pressure from the rock above is placed on the remaining coal pillars, causing "extreme squeezing," Mr. Oppegard said. Sometimes that is enough to cause a pillar to explode, leading to a collapse.

It is also possible that a planned pillar removal can cause the roof to collapse beyond the row of pillars being cut.

In October, the Mine Safety and Health Administration put three mining operations -- out of nearly 15,000 in the nation -- on notice of a pattern of violations, including Brody Mine No. 1.

"A POV notice, one of the agency's toughest enforcement actions, is reserved for the mines that pose the greatest risk to the safety of miners," said an administration news release at the time.

The Brody mine received 253 "significant and substantial" violations.

A federal audit found that injured miners accounted for 1,757 lost work days at the mine. Of those, 367 lost work days stemmed from eight injuries that Brody failed to report, the news release said.

Patriot disagreed with the federal government's description of its safety record.

"During the period of time it has operated as a Patriot subsidiary, the Brody mine has made considerable and measurable progress toward improved safety and compliance," Patriot said in a statement responding to the government findings.

Patriot acquired Brody Mining at the end of 2012.

"Many of the violations and the severity measure cited in the POV finding took place under the prior owner," Patriot said. "Immediately following Patriot's purchase of Brody, on January 3, 2013, the company submitted a Compliance Improvement Plan to MSHA. Since that time, the Brody mine compliance performance (as measured by violations per inspector day) has improved by 40 percent."

Patriot also said it replaced all former officers and "key mine-level managers" at Brody.

In September Patriot submitted a Corrective Action Plan to MSHA, which was approved.

Mr. Oppegard, however, noted that violations have continued into 2014, with the most recent listed on the MSHA website from May 7.

Three violations from this year were problematic enough to be considered red flags, he said.

First Published: May 13, 2014, 1:01 p.m.
Updated: May 14, 2014, 3:35 a.m.