A figure from the MSHA report shows the UBB mine with projected fault zone and locations of joints (green, blue), slickenslides (red) and floor burst locations (purple). Click to enlarge the image.
More to the point:
Investigators interpret the fault zone to represent a conduit for methane migration into the Eagle seam from a reservoir that was ultimately sourced in organic-rich Devonian shale.
Now, the MSHA report also points out:
… The mine map indicates that Panel 18 was terminated short of its intended length. This termination coincides with a projected (imaginary) diagonal line connecting the 2003 and 2004 outbursts … [Performance Coal Company] and Massey stopped several longwall panels along the projected fault zone.
But the report also explains:
Another factor in the release of methane appears to be the overburden present above the fault zone. While other panels mined through the fault zone without experiencing a methane outburst, those panels encountered overburden depths much less than 1,000 feet within the fault zone. the panels that experienced methane outbursts encouraged overburden values of over 1,150 feet. It appears that several longwall panels, including Longwall Panels 11, 12, and 18 and Longwall Panels 16 and 17, wee terminated in the vicinity of where the projection of the fault zone intersected the 2,000-foot topographic contour. This corresponds to between 1,125 and 1,200 feet of overburden, depending on the seam elevation.
Yeah … we’re getting a little deep in the weeds now. So what does all this mean? Flip back to page 6, which is part of the Executive Summary of MSHA’s report:
A small amount of methane, likely liberated from the mine floor, accumulated in the longwall area due to poor ventilation and roof control practices.
Based on physical evidence, the investigation concluded that methane was likely liberated from floor fractures into the mine atmosphere on April 5, the day of the explosion. The investigation team subsequently identified floor fractures with methane liberation at longwall shields (a system of hydraulic jacks that supports the roof as coal is being mined) near the tailgate, the end of the longwall where the explosion began. This methane liberation occurred because PCC/Massey mined into a fault zone that was a reservoir and conduit for methane. MSHA believes that this is the same fault zone associated with methane inundations at UBB in 2003 and 2004, and in a 1997 methane explosion.
Also, check out Citation No. 8227560, one of the contributory violations issued by MSHA yesterday to Performance Coal and Massey Energy:
The mine has a history of methane incidents on prior longwalls panels. These incidents put the operator on notice for methane hazards on the longwall face. These incidents include:
– A methane ignition / explosion that occurred on 1/4/1997 at No. 2 West Longwall.
– A methane outburst that occurred on 16 Longwall panel in July of 2003
– Another methane outburst occurred on 17 Longwall panel on 2/18/2004
These incidents all occurred in a fault zone and while mining with an overburden in the excess of 1,000 feet. The accident on 4/5/2010 occurred in this same fault zone.
The citation goes on:
The operator failed to implement / follow the recommendations of MSHA’s geologist and Ventilation technical support group following the 2004 outburst. These recommendations included:
— Increasing airflow along the longwall face (the plan at the time required a minimum of 60,000 cfm).
— Degasification wells for the subsequent longwall panels in an effort to bleed gas prior to encroachment of the longwall face.
— Construct a hazard map that showed areas with 1,100 feet of overburden and less than 13 feet of interburden between the eagle and lower eagle seams. Additionally, this map should show the projected structural zone identified in headgate 18, and overmined areas.
The operator’s failure to maintain a sufficient volume and velocity to dilute, render harmless, and carry away flammable, explosive, noxious, and harmful gases, dusts, smoke and fumes contributed to the deaths of 29 miners.
What’s not said there is what MSHA has partly acknowledged already, that agency officials never made sure Massey implemented these recommendations or some other plan to avoid methane doing exactly what it did on April 5, 2010. I say partly, because MSHA has not really explained in any detail how in the world this could have happened, which agency officials exactly were responsible — let alone how they have been punished or what steps have been taken to ensure the same thing doesn’t happen again.
I asked Joe Main about this yesterday during MSHA’s press conference at the mine academy in Beckley. He said the issue is one of those being examined by MSHA’s internal review team, whose report has not yet been completed or made public. But Joe was quick to add:
One of the things we can’t miss here is … the mine operator had the information that was available on how to address the problem.
Yes, it’s true that the primary duty to protect miners and provide them with a safe workplace is that of the mine operator. But what’s the point of having an agency like MSHA if it’s job isn’t to make sure operators do that. MSHA is fond of saying that its inspectors can’t be in every mine every hour of every day. That’s true — but this is a situation where MSHA knew about not one, not two, but three previous methane incidents at the same mine, knew what the underlying cause was, and recommended steps to fix the problem. Was it too much for the families of 29 coal miners to expect that MSHA would ensure appropriate steps wee taken?
Just 10 days after the Upper Big Branch Mine blew up, President Obama made a bunch of promises to the people of the country and our nation’s coalfields. Among them:
… We can’t just hold mining companies accountable — we need to hold Washington accountable. And that’s why I want to review how our Mine Safety and Health Administration operates … Even so, we need to take a hard look at our own practices and our own procedures to ensure that we’re pursuing mine safety as relentlessly as we responsibly can.
Step 1 might be for MSHA to immediately release the rest of its documents concerning the previous methane incidents at Upper Big Branch, and hold a public briefing to explain exactly how this particular failure by the agency could have happened.