During a press update on Friday, MSHA coal administrator Kevin Stricklin and assistant secretary of labor for mine safety and health Joe Main said the investigation of the mine was about 90% complete.

MSHA has taken about 250 pieces of evidence from the mine, as well as 1803 rock dust samples.

However, the two officials revealed about 79% of those samples – or about 1400 – have been deemed non-compliant to federal standards for rock dusting.

MSHA outlines that noncombustible material must equal 65% in intake areas and 80% in returns.

Most of the samples taken to date have come from the areas affected by the explosion in April that took the lives of 29 workers, though MSHA noted that the analysis of the results was ongoing.

At this point, Stricklin confirmed, it was “fair to say” that dust played a role in the incident.

“We just aren’t in a position to say how big of a role,” he said.

Main and Stricklin also reported in their update that the electrical portion of the investigation was also progressing, with 11 multigas detectors recovered to date – five from the Headgate 22 area, two from the headgate area of the longwall and another one from the longwall face.

Three were located on the mantrip at crosscut 78 where some of the killed miners were found.

The agency is still searching for more handhelds, and the location of the second remote control for the UBB longwall remains unknown.

Stricklin also noted that the information pulled from the gas detectors so far has helped investigators pinpoint a timeframe for when the incident actually occurred.

Preliminary data has provided a window between 2.59pm and 3.06pm on April 5.

Federal officials are also beginning to wrap up the individual interview portion of the investigation, with 235 completed and another 20 left to be conducted.

MSHA confirmed it was still considering whether or not it would interview Massey chairman Don Blankenship.

Massey officials focused on the coal dust allegations portion of MSHA’s update in its response Friday afternoon.

“This is not the first time MSHA has attempted to use unproven or faulty coal dust claims in their investigation efforts,” a spokesperson said.

“In the 2005 legal proceeding MSHA v Jim Walter Resources, Inc, federal investigators had their coal dust theories rejected when they used contaminated, two-month-old post-accident dust samples and falsely asserted they were representative of non-compliant coal dust levels immediately preceding a mine explosion.”

In its separate investigation of Upper Big Branch, Massey said MSHA was using the same dust specialist used in the JWR case, Clete Stephan.

MSHA is also using the same dust collection techniques as those rejected in that case’s proceedings by an administrative law judge.

“Unfortunately, MSHA has failed to learn the lessons from its prior investigative mistakes,” Massey officials said.

“MSHA’s narrow-minded focus on compromised coal dust evidence is doing a disservice to those UBB families entitled to concrete answers unequivocally supported by accurate scientific findings and the facts.

“Sadly, MSHA appears to be more interested in proving itself right, even if the evidence suggests the agency’s presumptions are wrong.”

The operator said it would make a copy of the MSHA v Jim Walter Resources, Inc. report available on its website for public review.

Keep watching International Longwall News for more news regarding the UBB blast and investigation.