December 1, 2011
Inflatable Refuge Chambers Versus Steel Chambers

Strata Worldwide’s Chamber Product Manager, Ryan Fielden, discusses steel versus inflatable refuge chambers, and how new regulation enforcements will affect upcoming purchasing of chambers

It wasn’t long ago that mine safety chambers were a novelty found mostly in international hard-rock mines. They had never seriously been considered in coal mining due to the inherently confined and highly mobile nature of the environment. A few years ago however, as the apparent need to provide emergency supplies of breathable air to miners trapped underground came to light, Legislature made it a requirement of all coal mines to have chambers underground. Solutions to overcome the limitations had to be found.

Strata Worldwide’s answer to this was developed in 2006 and 2007 with the introduction of the Portable Fresh Air Bay (FAB). The FAB is an inflatable refuge chamber housed in an explosion resistant steel skid along with compressed air and oxygen cylinders and a carbon dioxide scrubber. The compressed air rapidly inflates the chamber in emergencies and the oxygen cylinders and scrubber maintain breathable air for the duration of 96 hours.

The steel skid is compact and rugged and optional wheels and tow hitch packages further increase its portability. The units are easily moved along as production progresses. Due to the compactness of the structure and the flexible sizing options, this design is the best option for mines with low seam heights and narrow entries.

The fabric of the inflatable chamber is very effective in heat dissipation, making the FAB ideal for use in mines with higher ambient temperatures.

Traditionally, mine refuge chambers are steel, walk-in units which remain readily available for fast access and an immediate source of breathable air. Strata adapted this design to be used in coal mining by replacing all electrically powered systems with air-powered or battery powered alternatives.  The structure of the chambers was altered by reducing the height and increasing the thickness of the steel to create a chamber to withstand overpressure up to 15psi. The Strata steel chambers can also be mounted on wheels and fitted with towing facilities to improve maneuverability. For coal mines with fewer height, width and temperature restrictions, the Strata steel chamber is a perfect option.

To date, all Strata chambers are West Virginia approved, meeting all requirements outlined in the regulations. Moving forward however, MSHA will enforce a list of revised regulations that will be required on all underground chambers. Modifications will be made to the Strata chambers.

 “With over sixty-five percent of the total market-share, Strata has 800 plus chambers currently underground. Each one of these chambers will have to come to the surface to be modified,” president and chief executive officer Rory Paton-Ash said.

“In order to enable our customers to remain in operation and compliant, we are offering a new chamber lease program in which they can lease a chamber from us for the time their chambers are removed for modifications.”

This option eliminates the need for mining companies to invest significant capital for the purchase of additional units. Once the customers’ chamber components have been modified and tested and are MSHA compliant, their units will be returned and then rental units removed.

In addition, the Strata leasing program extends to mines that need to purchase a chamber prior to MSHA approved units becoming available. Once MSHA units are available, customers can either return the rental units and purchase MSHA approved chambers, or continue a rental program with Strata on new, MSHA approved chambers.

For more information please contact Ryan Fielden at 1-800-691-6601 or