The Ocenco M-20  shown donned and ready for escape.

There’s an update just out from the U.S. Mine Safety and Health Administration about the latest problem with self-contained, self-rescuers that coal miners depend on in case of an underground fire or explosion. Recall that we discussed problems with the Ocenco M-20 in a post last week. At the time, this was pretty much all MSHA had to say about the matter:

MSHA and NIOSH have initiated a joint investigation concerning Ocenco M-20 Self-Contained Self-Rescuers (SCSRs). The investigation began as a result of a malfunction reported to MSHA involving four Ocenco M-20 units manufactured in 2008 and found at one mine. As is usual practice, MSHA and NIOSH are investigating further. MSHA is also contacting mine operators to make sure required tests of SCSRs are being conducted and to assure that any defect, performance problem, or malfunction of an SCSR is reported to MSHA as required.

What we know now is that the issue started with a problem at CONSOL Energy’s Enlow Fork Mine in southwestern Pennsylvania:

Initially, a group of six SCSRs were tested by the mine operator at the Enlow Fork Mine in southwestern Pennsylvania.  The mine operator reported that four units failed to operate properly.  The individual who recorded the test results indicated that one unit expended all of the oxygen upon activation, “… in a matter of seconds.”  He also reported that the other three units did not provide oxygen.  The operator also reported that four more M-20 SCSRs were opened and tested the next day at the mine without any problems.

And according to MSHA:

Additional Ocenco M-20 SCSRs from the mine were tested at NIOSH and at the mine.  Five of six M-20 SCSRs tested at NIOSH on a simulator functioned properly.  The sixth SCSR supplied oxygen for 8 minutes instead of the required 10 minutes.  This unit did not malfunction when refilled at Ocenco and tested on a human subject.  MSHA and NIOSH continue to analyze the results of the simulator test.  With MSHA and NIOSH personnel present at the Enlow Fork Mine, the miner who reported the original malfunctions successfully tested three additional M-20 SCSRs.

There’s more on what the MSHA and NIOSH have done so far:

The SCSR inventory, which is based on information provided by mine operators, indicates there are approximately 23,000 M-20 SCSRs at underground coal mines.  Since 2009, NIOSH has tested 149 M-20 SCSRs from mines throughout the country as part of its field testing program.  All of these SCSRs functioned on the simulator.

As reported in the April 19^th Notice, MSHA surveyed all operating underground coal mines to identify any problems with Ocenco M-20 SCSRs.  The survey revealed that mine operators had tested 275 M-20 SCSRs at 244 mines within the past year as required by MSHA policy.  The MSHA survey identified problems affecting four Ocenco M-20 SCSRs.  At one mine, the mine operator reported that two M-20 SCSRs had malfunctioned during testing; however, the miner conducting the tests did not don the units and therefore did not inhale to activate the demand valves.  At another mine, the mine operator reported that two other M-20 SCSRs had malfunctioned because the miner who performed the tests indicated that the SCSRs did not appear to activate at first.  However, both SCSRs worked when the miner breathed into them.

MSHA and NIOSH received additional information from Ocenco in their response to the reported malfunctions.  Ocenco reported that they activate all M-20 SCSRs that are returned for refurbishment, and have not observed any problems.  Ocenco also tested 12 M-20 SCSRs from units returned for refurbishment.  These SCSRs had manufacturing dates similar to the units reported to have malfunctioned at the Enlow Fork Mine.  Ocenco reported that none of these SCSRs malfunctioned.

And here’s their conclusion:

MSHA and NIOSH continue to investigate the issue, but at this time it appears that the reported problems resulted from the manner in which the SCSRs were tested.  Accordingly, MSHA and NIOSH have discussed with Ocenco the need to develop and publish procedures for mine operators to use when testing M-20 SCSRs.