This weekend's testing of two methane monitors from the Upper Big Branch coal mine in West Virginia has not detected any evidence of tampering, NPR has learned.
The methane monitors were removed from the longwall mining machine believed to be a possible ignition source of the April 5 explosion that killed 29 mine workers. Investigators have been anxious to inspect and test the monitors, given reports that similar safety devices had been disabled on other mining machines in the mine.
Disabling methane monitors permits continued mining of coal even if the monitors malfunction or they detect levels of methane that approach explosive concentrations. The practice is considered dangerous and illegal because monitors are designed to display warnings and shut down mining machines when methane levels get too high.
This methane monitor is the make and model of the monitors recovered from a longwall mining machine in the Upper Big Branch coal mine, according to Ronald Wooten of the West Virginia Office of Miners' Health Safety and Training.
A source familiar with this weekend's testing says there was no evidence found that the monitors had been tampered with or disabled just before the massive explosion in April.
That assessment was confirmed by Ronald Wooten, director of the West Virginia Office of Miners' Health Safety and Training, who has been briefed about the testing. Wooten declined to comment pending a detailed internal briefing Monday.
Wooten and the source also say that testing of the monitors confirms that they are in working condition and able to detect methane gas at levels that would automatically shut down the mining machine.
The testing took place all day Saturday at the federal Mine Safety and Health Administration's technical center in Triadelphia, W.Va. Representatives of the state and federal mine safety agencies were present, along with accident investigators and observers from mine owner Massey Energy, the United Mine Workers union and CSE Corp., the manufacturer of the monitors.
Components of the monitors were removed from the longwall mining machine deep inside the Upper Big Branch mine on July 21 and July 27, and kept in a secure location until testing could be scheduled this weekend.
Testing continues next week on a 1,000-foot-long cable, or "tensioner," that ran between the gas "sniffing" sensor at one end of the longwall machine to a digital readout device at the other end.
Investigators are also testing a data recorder from the longwall mining machine. It contains information about the operation of the mining machine and the monitors at the time of the blast and at least six days before. That testing is taking place at a Joy Manufacturing facility in Franklin, Pa. Joy is a major producer of mining machines.
Amy Louviere, a spokeswoman for the federal Mine Safety and Health Administration, says findings of this weekend's testing won't be publicly revealed until after a Tuesday night briefing in Beckley, W.Va., for the families of the disaster's victims. "We won't be able to talk about these issues until after the family meeting," Louviere says. "That's always been our policy."
Massey Energy did not respond to a request for comment Sunday about the testing.
The fact that the monitors are in working condition and do not appear disabled deepens one of the mysteries about the explosion. The blast is believed to have been triggered by the ignition of methane gas, which naturally occurs in coal mines and is especially prevalent in the Upper Big Branch mine. But if the monitors were working properly, the mining machine should have shut down before its cutting blades or other equipment could have provided the spark that presumably ignited the gas.
Massey Energy has floated a theory that a sudden and massive outburst of methane overwhelmed the safety devices, but there's no evidence of a large accumulation of the gas until 5 1/2 hours after the explosion. Also, the "black box" data recorder has provided evidence that methane levels were relatively low before the blast.
Investigators are keenly interested in recovering and inspecting two other methane monitors installed on two other mining machines also in portions of the mine hit by the explosion.
These monitors are mounted on much smaller continuous mining machines, and they're also considered possible sources of ignition. But flooding in the mine has kept investigators from reaching those mining machines so far.
NPR has documented an incident in February in which a methane monitor on a different continuous miner in another section of the mine was deliberately disabled at the direction of a mine official. Multiple witnesses have told NPR that the mining machine then continued to operate without a working monitor, which is a possible criminal act. The FBI and a federal grand jury have interviewed several witnesses to the incident.