According to the agency, an Alabama coal operator was assessing the effectiveness of the foam product in an abandoned conveyor belt entry, and whether the product could be used in a large-volume application by pumping through a vertical borehole from the surface to the test site.

The operated wished to determine if Meyco MP 367 could be a possible method for isolating a mine entry in an emergency.

While the initial testing day occurred without incident, a fire developed on the second day about five feet from the right rib of the belt entry at the mine floor of the foam application.

“The fire propagated over 200 feet burning conveyor belting, timber supports, coal and the foam,” MSHA said.

“The fire took over 90 minutes to extinguish [and] there were no injuries.”

Federal officials have not yet determined the cause of the fire, and MSHA is working with both BASF and the mine operator to investigate the incident and determine cause.

“At this time, there is no assurance that Meyco MP 367 foam does not pose a fire hazard in coal mines for use in remote sealing applications, including roof-rib injection and consolidation,” MSHA added.

“Until the investigation of the incident is completed and the cause of the fire determined, MSHA is issuing [an] alert to make mine operators aware of potential fire hazards associated with the use of the … foam.”

BASF’s Meyco MP 367 foam was designed for injection application to fill cavities rapidly and also for coal and rock consolidation in mines and tunnels.

Once the product is applied, it immediately expands to up to 30 times its original volume and sets in minutes.