Coal Tattoo

Slurry safety: Learning from the CONSOL collapse

It’s been nearly a week since the terrible collapse of a “saddle dike” at CONSOL Energy’s Robinson Run complex  in Harrison County, W.Va. Crews are still looking for the body of a United Mine Workers dozer operator who was killed when he and his machine were dumped into the operation’s huge Nolan Run slurry impoundment.

Thinking of what the man’s family must be going through is really unimaginable.  I couldn’t help but recall the congressional testimony more than six years ago from Wanda Blevins, whose husband’s body lay underground for 43 days until it was retrieved by rescue teams after the September 2001 explosion at the Jim Walter No. 5 Mine in Brookwood, Ala. Crews had flooded the mine to put out a fire and ensure a safety recovery. I couldn’t help remember that, not far from Robinson Run, the bodies of 19 of the 78 victims of the Farmington Mine Disaster in Marion County remain forever entombed in the tunnels of that CONSOL operation.

This isn’t the first time in recent memory that working around a coal-slurry impoundment became a deadly proposition for a coal miner. For example, there was this incident in June 2002 at Arch Mineral Corp.’s Lone Mountain Processing site in in Lee County, Va.:

… At approximately 5:50 a.m., 49-year-old Willie Holmes, Jr. was fatally injured when the truck he was operating overturned into a coal slurry impoundment. The victim was backing a Model 773B Caterpillar 50-ton off-road truck along a haulroad to a designated dumping location when the truck went through the berm approximately 25 feet short of the dump, causing the truck to roll/slide down the slope and overturn into the impoundment. The victim was recovered from the impoundment at 1:25 p.m. and was transported to the Lee Regional Medical Center in Pennington Gap, VA where he was pronounced dead on arrival.

In their report, MSHA investigators concluded, among other things:

The provided roadway berm was not properly maintained. The berm was recently constructed and was composed of unconsolidated material. Since this section of roadway was almost zero percent grade and had no outlet for drainage, any water falling or flowing onto the roadbed was impounded. This caused the berm to become saturated and thus lose its function as a warning that the truck was nearing the outer edge of the roadway.

We’re far from having all of the facts in about what happened at the Nolan Run impoundment. But some details are starting to emerge, as we reported in this morning’s Gazette:

Federal and state records showed previous questions about stability and leaks at the Nolan Run impoundment, and outlined company concerns that construction to enlarge the dump had not been moving fast enough to keep up with slurry waste generated by the preparation plant at CONSOL’s nearby Robinson Run Mine.

The embankment that collapsed last week was part of a “saddle dike” that CONSOL was building to help raise the overall height of the facility to accommodate more slurry. CONSOL proposed the saddle dike on the opposite end of the facility from the main dam, to raise the embankment in a low spot, or “low gap”, in the surrounding topography.

State Department of Environmental Protection officials had approved that expansion in April 2009.

But earlier this year, CONSOL told DEP officials that the construction had been hampered by “an unusually wet fall and a mild winter” that “made it difficult to maintain the extended haul road and proper placement of embankment fill during inclement weather.”

CONSOL was concerned that the timing of the project’s completion “may be very close or even lag behind the filling of the pool with slurry,” a company engineer told DEP in a March 2012 letter.

The company submitted another plan for an “intermediate stage” impoundment expansion. DEP approved that proposal on June 18, 2012.

Jim Pierce, a DEP dam safety engineer who is investigating Friday’s incident, said such issues are fairly common at impoundments as coal operators try to ensure space to dispose of preparation plant wastes.

“They have to stay head of the slurry,” Pierce said. “It’s always a concern.”

And Pam Kasey over at The State Journal reported, along those same lines:

The work that was going on at Robinson Run, an “upstream pushout” — that is, pushing coarse mine refuse out to pile up on the “upstream,” or “inside” side of a dam to, over time, expand its foundation and increase its height — is conducted regularly, mine experts say.

So, why did this one collapse?

The simple, almost self-evident answer: Someone pushed construction too far, too fast.

“You’re basically pushing the refuse almost into a swimming pool, so it gets saturated,” said Dennis Boyles, regulatory program specialist in the Office of Surface Mining Reclamation and Enforcement’s Charleston field office, in an unofficial assessment of the situation. “Apparently they had overextended it.”

The process has a relatively narrow range of tolerance for stability, said economic geologist Alan Stagg, president and CEO of Stagg Resource Consultants in Cross Lanes.

“You’re on top of it trying to build it up and if you don’t watch it you’re going to go beyond that threshold,” Stagg said. “Somebody just pushed that process too far and got to where the underlying material was saturated and it just yielded.”

As Pam explains:

That’s the simple answer. The more complex answer will take months of investigation.

Was CONSOL rushing this construction because of its pressing need for more space to put the massive amounts of slurry waste generated by the preparation plant that cleans coal produced by the longwall mining at its Robinson Run plant, which feeds FirstEnergy’s nearby Harrison Power Station? Hopefully, state and federal investigators will definitively answer that question. Hopefully, they’ll also be transparent and straight-forward about whether state and federal permit reviewers and inspectors missed anything that played a role in this tragedy. One thing we do know is that CONSOL got the longwall mining up and running by yesterday morning at Robinson Run, and is eager to again begin pumping slurry into the Nolan Run impoundment, perhaps even before the body of the missing dozer operator is located and recovered. As we reported today:

CONSOL was also seeking approval from the U.S. Mine Safety and Health Administration to restart its coal-cleaning plant. Company officials released a diagram showing a large boom being placed across the impoundment, to isolate active slurry disposal areas from the section where the dozer is located and said the move “will not interfere” with recovery of the missing miner.

Of course, every accident at a coal-slurry impoundment in this part of the world brings to mind the February 1972 Buffalo Creek Disaster, when the failure of a series of dams in Logan County, W.Va., claimed the lives of 125 men, women and children. And this incident at Robinson Run comes as citizen groups continue to question the very sort of “upstream construction” practice that was being used at the collapsed saddle dike: Building coal-refuse impoundment embankments by placing coarse coal refuse — the larger pieces of waste — on top of other refuse, often much finer pieces, hoping that the wet fine refuse has dried, hardened and stabilized enough to serve as a proper foundation.

In her story earlier this week, Pam Kasey quoted longtime dam safety expert Jack Spadaro outlining the concerns about this practice:

“So you’re building a dam on top of slick, wet, fine material,” he said. “It is not a sound way of engineering these structures.”

Regulations allow for building on fines at a small scale under controlled conditions, he said, adding “it’s been very successful, especially through the ’70s and ’80s.”

But, he said, enforcement of the regulations has slipped.

“What I’ve found is through the ’90s, particularly through the administration of George W. Bush, there was a relaxing of vigilance on the part of federal agencies that were supposed to be responsible for these dams and, unfortunately, that has continued into the first four years of the Obama administration.

“We’re loading up the tops of these dams now with an enormous amount of material and they’re pushing out into these reservoirs farther and farther and they’re going higher up,” he said. “It could be done on a limited basis very carefully but should not be done on such a large scale.”

Large structures like the Robinson Run impoundment should be built complete from the beginning, in Spadaro’s mind. Or dams should be expanded not from the inside, but from the outside — a more expensive process, but one that could be conducted dryly and safely.

He charges the state and federal agencies with failure to carry out their responsibilities and asserts that studies have been conducted within OSM and MSHA that confirm that but not have not been released to the public.

“It’s not a story just confined to Harrison County; it’s a national problem,” he said.

U.S. Office of Surface Mining Reclamation and Enforcement officials have clashed with the WVDEP over citizen complaints that this process has led to problems at the former Massey Energy’s huge Brushy Fork slurry impoundment in Raleigh County (see here, here and here). And there’s been a big study by OSM going on aimed at examining concerns about compaction issues at impoundments across the state’s coalfields.

OSM was supposed to make results of that study public as part of the release of its 2012 annual oversight report of the WVDEP’s Division of Mining and Reclamation … but both those study results and the annual oversight report are behind schedule in being made public … stay tuned …