TORONTO (miningweekly.com) – A coal mine explosion that killed 29 people in West Virginia last year was probably caused by faulty water sprays, badly managed ventilation and built-up coal dust, and could have been prevented, US Department of Labour officials said on Wednesday.
Mine and company management were aware that chronic hazardous conditions were not being recorded properly and miners were “intimidated” into prioritising production over safety, administrator for mine safety and health Kevin Stricklin said at a public briefing to mark the one-year anniversary since the Mines Safety and Health Administration (MSHA) started its probe into the accident.
The Upper Big Branch mine was owned by Massey Energy, which was acquired this year by Alpha Natural Resources. The accident was the worst at a US coal mine in four decades.
“This explosion could and should have been prevented by the mine operator,” Stricklin said.
Stricklin said that evidence did not support Massey's claims that the explosion was caused by a sudden, unforseen inflow of gas. A crack in the floor, which Massey had identified as the likely source of the gas, was found to be 'rootless', which means it was not connected to an area containing combustible gas.
The explosion was most likely started by a limited amount of methane or natural gas, probably ignited by the longwall shearer, he said. The ignition was allowed to occur because of missing and faulty water sprays.
The methane ignition then transitioned into a “massive” coal dust explosion, which again could have been prevented if the dust was not allowed to build up and other safety procedures were correctly followed, Stricklin said.
There had actually been 37 reported ignitions in US mines during the year leading up to the Upper Big Branch disaster, none of which resulted in injuries to the people involved, he said.
“Certain things need to be in place so that the ignition doesn't turn into a massive explosion.”
A company safety examiner actually reported conducting a methane gas check in the hours leading up to the explosion, but the methane detector showed it had not been turned on between March 18 and several hours after the incident happened on April 5, Stricklin said.
TWO SETS OF RECORDS
MSHA also said it discovered that the mine kept two sets of records, with reports of hazardous conditions often left out of the official books, which are reviewed by MSHA and required by law, and only recorded in the internal production and maintenance reports.
Alpha Natural will look at the information made available by MSHA as part of its own review of the incident at Upper Big Branch, Alpha Natural spokesperson Rick Nida said.
"We heard this information from MSHA at the same time that everybody else did," he told Mining Weekly Online.
"Our review is really in the early stages, we are just starting to assemble specialists as part of the team. And when the full MSHA report is made available, it will be part of the information the team reviews closely."
The agency's investigation is still under way, but is nearing completion, assistant Secretary of Labour Joe Main said. A final report will likely be published later this year.
The MSHA investigation has involved interviews with 266 people, 1 060 pieces of physical evidence, 23 000 photographs and 84 000 documents. Eighteen managers from Massey Energy and subsidiary Performance Coal declined to be interviewed.
The US Department of Justice is also conducting a separate, criminal investigation into the incident.
The company said on June 3 it would conduct its own review into the explosion at Upper Big Branch, and would cooperate with the government investigations.
Alpha Natural also distanced itself from a document published by former Massey chairperson Bobby Inman, which repeated Massey's assertion that the explosion was caused by a massive inundation of natural gas.
Inman's document disputed the findings of an earlier independent report, insisting that the mine was properly rock dusted, and that there was "no evidence" to suggest the mine's ventilation system played any role in the explosion.