MSHA issues ETS for rock dust

AS safety officials suspect that coal dust played a role in the Upper Big Branch mine disaster this year, the US Mine Safety and Health Administration is introducing tougher standards on rock dusting to prevent coal dust explosions.
MSHA issues ETS for rock dust MSHA issues ETS for rock dust MSHA issues ETS for rock dust MSHA issues ETS for rock dust MSHA issues ETS for rock dust

Coal dust explosions such as this demonstration can be prevented by the addition of sufficient rock dust.

Donna Schmidt

Last week the agency said that the ETS, published Wednesday in the Federal Register, seeks to strengthen the protection of workers and keep the potential for coal dust-related explosions at a minimum.

MSHA officials opted to create the ETS after evaluating the investigation reports of mine explosions logged in intake air courses that involved coal dust.

It also considered a report from the National Institute for Occupational Safety and Health, “Recommendations for a New Rock Dusting Standard to Prevent Coal Dust Explosions in Intake Airways”.

The emergency temporary standard is effective immediately, and applies only to bituminous coal operations.

MSHA issues a public information bulletin for operations to provide guidance to operators on methods for compliance to the new standard.

“Coal dust can cause explosions, and explosions kill miners,” secretary of labor Hilda Solis said.

“Inadequate rock dusting can dramatically increase the potential for a coal mine explosion. Compliance with the new standard will strengthen the protection for miners by minimizing the potential for such an explosion and, ultimately, will save lives.”

MSHA assistant secretary Joe Main added that the explosions linked to coal dust were violent and deadly.

“When the NIOSH report was released in May 2010 containing new scientific evidence that called for a higher standard, MSHA moved quickly to get this new standard in place,” he said.

“We also revised our guidance on rock dusting to ensure that mine operators are taking the steps necessary to provide for the safety of everyone working in their mines.”

Under existing MSHA standards, US operations must maintain 80% or more of total incombustible content (TIC) of combined dusts in return air courses, and at least 65% TIC in other areas.

It also mandates an increase in TIC percentage in all areas underground where methane is present in any ventilating current.

The 80% TIC must be upped by 0.4% for each 0.1% methane in returns, while the 65% TIC in all other areas must be increased by 1% for each 0.1% methane present.

Under the ETS, the total incombustible content of combined coal dust, rock dust and other dust must be increased from 65% to 80% in all accessible areas of underground bituminous mines, with an additional 0.4% for each 0.1% methane where methane is present in any ventilating current.

While the new emergency temporary standard is now effective, MSHA said it was allowing additional time for mines to purchase more rock dust-related equipment and materials, and is ordering all operators to comply with the new standard by October 7 in newly mined areas, and November 22 elsewhere.

In order to meet compliance deadlines, federal officials are urging operations to begin rock dusting immediately.

All mines should place priority on areas that pose the greatest risk to miner safety, such as near active faces, and in areas where possible ignition sources could be found including conveyor belt drives and belt entries.

“We know that it will take mine operators a little bit of time to bring their mines into compliance with the new standard,” Main said.

“But coal dust explosions are serious, and we expect mine operators to act quickly to reduce the threat to those mining coal underground.”

The NIOSH report “Recommendations for a New Rock Dusting Standard to Prevent Coal Dust Explosions in Intake Airways” can be reviewed in its entirety at