Dangers of ‘pulling pillars’ long known in coal industry
Last August, the Obama administration issued a news release to brag that the coal industry had “virtually eliminated” deaths from a dangerous practice known as retreat mining. The U.S. Mine Safety and Health Administration release, dated Aug 5, 2013, touted a five-year stretch from 2008 to 2012 with no miners killed by this practice, which involves removing coal from pillars that were left in place to hold up a mine’s roof.
The next day, a Harlan County, Ky., miner was killed and two other workers were hurt while they were “pulling pillars” in an Arch Coal mine called Huff Creek No. 1. Fifty-six-year-old Lenny Gilliam was buried beneath rock and coal. It took co-workers more than 2 and a half hours to dig out his body.
Then, last week, two West Virginia miners — Eric Legg of Twilight and Gary Hensley of Chapmanville — died while working on a retreat mining operation at Patriot Coal’s Brody Mine No. 1, in Boone County.
Retreat mining deaths are back. Mine safety regulators have spent the past four years stepping up enforcement and tightening explosion-prevention rules in response to the deaths of 29 miners in April 2010 at the Upper Big Branch Mine, in Raleigh County. It’s less clear how much attention has been paid during that time to the hazards associated with retreat mining.
In the wake of the Brody deaths last week, some longtime safety advocates have responded with calls to eliminate the practice.
“It’s Russian roulette,” said mine safety expert Davitt McAteer, who ran MSHA during the Clinton administration. “It should be abolished.”
Coal industry officials disagree, saying that, if done properly, retreat mining is safe.
“We’ve been through all kinds of debate on this,” said Bill Raney, president of the West Virginia Coal Association. “It’s very regulated. You have to have a plan. It’s a studious practice and one that people take very seriously while they’re doing it.”
MSHA chief Joe Main isn’t moving to join in McAteer’s call to outlaw retreat mining. In an interview, Main did not commit to any new initiatives aimed at retreat mining but simply promised a full investigation of what happened at Brody — something he said MSHA does whenever coal miners are killed on the job.
“With any of those fatalities that we have, are we going to be taking a harder look to figure out what went wrong? The answer to that is yes,” Main said.
Mining that uses continuous-mining machines to cut into coal seams leaves behind pillars, or columns, of coal, to help support the mine roof and control the flow of air. Retreat mining’s goal is to recover as much coal as possible by pulling those pillars from areas that already have been extensively mined.
In retreat mining, workers back out of the mine, removing pillars as they go. The roof caves in behind them. These cave-ins are intentional, and the theory is that they help to relieve pressure on the few pillars that remain. However, the practice is tricky and must be performed carefully. Larger roof falls than intended can occur, and — as apparently happened at the Brody Mine — increased pressure on remaining pillars can literally explode those pillars in a “coal outburst” that sends coal and rock blasting into the work area and onto the workers.
“Pillar recovery creates an inherently unstable situation,” experts from the National Institute for Occupational Safety and Health said in a December 2003 report. “Man-made supports cannot carry the full weight of the overburden. The roof at the pillar line is subjected to severe stresses and deformations. The ground will cave in, the only question is when.”
That same NIOSH report concluded that a miner working in retreat mining is three times more likely to be killed on the job by a roof fall or ground failure than an underground miner performing other kinds of work.
‘Deep cover’ report
Over the years, there have been periodic efforts to focus on retreat mining safety, and even some pushes to get rid of the practice. The most recent focus came in 2007, after six miners and three rescue workers died in the collapse of Murray Energy’s Crandall Canyon Mine in Utah during retreat mining. Crandall Canyon involved a massive coal-and-rock outburst in an operation that was mining as much as 2,200 feet below the surface.
Initial reports indicate that the Brody deaths were caused by a violent coal-and-rock outburst.
Eugene White, director of the West Virginia Office of Miners’ Health, Safety and Training, said workers at Brody were mining about 1,000 feet below the surface, a depth that White said “makes us look” at the potential for increased roof pressure to cause problems. The roof at Brody also was heavy sandstone, which can provide protection against typical sorts of roof falls where smaller roof rocks break and collapse, but also presents increased danger from extra pressure associated with the strong, heavy roof.
Just months after Crandall Canyon, when writing the federal budget, Congress ordered NIOSH to conduct a detailed study of the dangers of retreat mining in especially deep underground operations.
NIOSH published that study, “Research Report on the Coal Pillar Recovery Under Deep Cover,” in February 2010.
The 82-page report provides interesting statistics about retreat mining. For example, the report notes that about one-quarter of the nation’s underground mines perform pillar recovery and that coal pillars account for about one third of the production at those mines.
“Retreat mining is a fundamental part of mining,” said Chris Hamilton, vice president of the West Virginia Coal Association and an industry member of the state Board of Coal Mine Health and Safety. “It has always been an integral part of the extraction process.”
However, pillar recovery accounts for less than 10 percent of all hours that miners work underground and, between 1989 and 2001, 25 percent of groundfall deaths in underground coal mines occurred during retreat mining. Pillar recovery at great depths accounts for even less coal production, and perhaps just one-half of one percent of all hours worked underground. Retreat-mining practices are concentrated in Central Appalachia, mostly in Eastern Kentucky and Southern West Virginia.
Retreat mining’s safety record improved somewhat in 2005 and 2006, when there was just one death nationwide during pillar recovery. The NIOSH report credited increased efforts by industry, MSHA and NIOSH to deal with the problem. Companies are using mobile roof supports, stronger roof bolts and leaving behind carefully engineered “final stumps” to help support mine roofs.
Still, the NOISH report said, the MSHA regulations that specifically address retreat mining “have not been updated in several decades, and therefore do not cover many of the new procedures and technologies” that can help prevent roof falls or coal outbursts.
To specifically address the threat of coal or rock outbursts, the NIOSH report recommended that all underground mine operators perform special studies, called “burst hazard assessments.” These assessments would identify “red zones,” where bursts were likely to occur, and exclude those areas from retreat mining.
Since the NIOSH report was issued, MSHA has not rewritten any of its formal regulations addressing outburst protection. Two years after NIOSH issued its report, MSHA coal administrator Kevin Stricklin put out a memo — called a “Program Information Bulletin” — to advise agency officials about the NIOSH findings. The memo, dated July 11, 2012, said MSHA “will be considering” the NIOSH findings when reviewing mining company roof-control plans.
In last week’s interview, MSHA’s Main pointed back to the five-year period when there were no retreat mining deaths anywhere in the country.
“That’s some indication that, for a long period of time, there must have been certain protections in place that brought that about,” Main said. “We have a number of operators who seem to have systems in place that function better than others do.”
Hamilton said, “The secret to success in retreat mining is strict adherence to those plans.” Mine operators generally do a good job with that, he said, adding, “That’s not to say that there is not an occasional excursion or deviation from those established procedures.”
Five months before MSHA declared that the 2008-12 streak showed “fatalities resulting from retreat mining have been virtually eliminated,” the run of zero deaths from the practice ended.
On March 22, 2013, continuous-mining machine operator Elam Jones and his helper, Dallen McFarlane, were pulling pillars deep inside Castle Valley Mining LLC’s Mine No. 4, a Rhino Resources operation in Emery County, Utah. A 7-ton piece of mine roof fell on them. Jones was killed and McFarlane was injured.
MSHA investigators concluded that the company’s roof-control plan wasn’t adequate to protect the miners. Sloughage of material from the mine wall had reduced the size of pillars, leaving inadequate roof support, MSHA said in a report issued in December. Roof bolt spacing and tunnel width were too wide. Mobile roof supports were spaced improperly.
“It should have been apparent to the mine operator that the site-specific roof-control plan for retreat mining . . . was not adequate for the hazardous conditions that were being encountered,” the MSHA report said. “The operator was aware of the worsening conditions, but elected to continue mining.”
Two months ago, when MSHA released its report on the Kentucky retreat-mining incident that killed Lenny Gilliam, the agency noted some issues that raised questions about its own performance at the Huff Creek No. 1 Mine.
The agency concluded that the roof-control plan at Huff Creek had not been followed but also that the plan wasn’t adequate for the mining and roof conditions workers encountered. Federal investigators complained that the company had a previous outburst at Huff Creek but didn’t report the incident. Also, the MSHA report said core drilling before the accident showed potential problems for retreat mining in the area where the fatality later occurred.
However, the MSHA report also notes that, just weeks before the fatal accident, federal officials gave Arch Coal’s Lone Mountain Processing subsidiary an analysis by agency engineers warning that it “would be inadvisable at this time” to conduct retreat mining in the area where the fatal burst eventually occurred.
“This statement in the technical report was another strong indication that mine management had an opportunity to reevaluate the conditions and retreat parameters,” the MSHA report stated. “Prior to the accident, the mine operator did not reevaluate the mining conditions or revise their mining after receiving the technical report provided to the company by MSHA.”
The MSHA report on the fatal accident did not explain what — if any — action MSHA took to force the company to do such a re-evaluation, other than simply giving Lone Mountain Processing officials a copy of the engineering report.
Tony Oppegard, a former MSHA staffer and longtime mine safety advocate in Kentucky, said agency officials clearly should have followed up on the engineering report before the fatal outburst.
Oppegard noted that Kentucky’s mine safety law requires mine operators to inform that state’s Office of Mine Safety and Licensing within 48 hours of the start of any retreat mining. Under the law, state officials must then ensure that all miners who will be participating in retreat mining are properly trained in the operation’s pillar removal plan.
That provision of Kentucky law was added in 2007, after lobbying by a group of miners’ widows, including Claudia Cole, whose husband, Roy, was one of two miners killed in an August 2005 roof fall at another Harlan County mine, Stillhouse Mining LLC’s Mine No. 1.
In the Huff Creek situation, Oppegard said, a federal provision like the one in Kentucky law could have forced MSHA to more closely oversee retreat mining before the fatal accident.
“What’s the point of sending a notice and saying ‘it’s not advisable to pillar in that area’ if you aren’t going to follow up?” Oppegard said.
Reach Ken Ward Jr. at firstname.lastname@example.org or 304-348-1702.