The roof was secured with bolts driven 12 feet into the rock. The face, a 10-foot high wall of coal, was abnormally quiet. There were no pops or cracks in the dark before the wall rolled on Jaime Olivas, a 10-year veteran coal miner who died from his injuries hours later on the way to the hospital in Rock Springs.
Bridger Coal Company operates the underground coal mine for Pacificorp, the parent company of Wyoming’s largest utility, Rocky Mountain Power. The mine supplies Rocky Mountain Power’s Jim Bridger coal fired power plant.
Wyoming’s state inspector of mines said he believed that both Olivas and the company, Bridger Coal, were free from fault in the accident that killed the Rock Springs miner, despite citing the company for a safety violation. The incident has set a precedent for a stricter interpretation of the rules. The company will now secure the coal face if miners are going to be working in front of the wall while removing the equipment that shears coal from the wall in an underground mine, said Terry Adcock, state mining inspector.
“Experience has shown us now, that we need to do that as a practice,” he said. ”Once you have the event, that is telling all of us that we can’t rely on the normal indicators. That tells us we need to do something.”
The Office of the State Mine Inspector completed an investigation into Olivas’ death recently and cited the company for not securing the wall before Olivas stepped out in the pan line to untangle mesh used to secure the roof. Olivas was protected from above, but not from the wall.
Adcock said that regulations, followed by both state and the federal regulators, require that roofs and walls be secured if workers are present in an area that is hazardous. In this case, there was no sign that the wall would roll, and so the situation was not read as hazardous by those present, Adcock said.
“Everyone said this was probably the best looking face that they had ever seen,“ Adcock said of the miners he interviewed after accident.
Longwalls are under tremendous weight; fissures can spread across the face hinting at weaknesses. Usually the wall creaks and pops before it falls. In this case, there were only seconds between a loud pop and the wall roll, he said.
The miners had observed the wall, following their safety guidelines, and had struck it with a long pry bar, listening for a sound like a drum that foretells hazard.
There was nothing.
The silence persisted when Adcock himself visited the scene soon after the wall collapsed, he said.
“To me, Bridger did everything right,” Adcock said.
The federal investigation into Olivas’ death was not complete by press time. Adcock, who worked with the federal team in preparing his own investigation, said it was likely that the Mine Safety and Health Administration would cite Bridger Coal, a subsidiary of the utility Rocky Mountain Power, for the same violation.
The federal regulators are also authorized to levy a fee for violations, which Wyoming is not.
A spokesman for Rocky Mountain Power declined to comment on the investigation.
Adcock said the company is in agreement with the new practice regarding rib safety.
A mining expert from the Colorado School of Mines, who was not a part of the investigation team, said regulators do not have much flexibility in terms of citing violations of the rules. If they see something, they have to note it, said Jurgen Brune, director of the Edgar Experimental Mine research for the Colorado School of Mines.
There is also pressure in circumstances where someone was gravely or mortally injured.
“The state probably feels like they have to cite the company for something, because ultimately the company failed to protect the employee,” he explained.
It is not abnormal that the wall face would have been unsupported if there were no signs of a weakness, Brune said.
“The face is where you mine the coal,” Brune said. “You can’t support that because then you couldn’t get the coal.”
That said, after mining is finished, and during the removal of equipment that Olivas was engaged in, miners would likely avoid standing where Olivas stood untangling mesh, he said.
Sometimes, you simply can’t avoid moving into dangerous positions in the course of the work, Brune said. But it is a location most would avoid.
“This is one of those unfortunate things where multiple freak things come together and somebody gets injured,” he said.
A representative from Olivas’ union, the International Brotherhood of Boilermakers, was part of the state’s investigation team. The union declined to comment on the state investigation.
Hayley McKee, a spokeswoman for the Wyoming Department of Workforce Services, said the event was tragic.
“We know that mining is inherently dangerous,” she said. “Our thoughts and prayers are with the family.”