Published in the May 2008 Coal USA Magazine

Once the unit has been worn, carried or stored on mobile equipment, it is no longer considered to be new and therefore is subject to a full daily inspection and an Acoustic

Solids Movement Detector (ASMD) test every 90 days. Once considered to be in use by a mine, it cannot be used as part of a SCSR cache.

However, the company added, cache units must also undergo inspections, the first being a visual when the pack is placed into its storage container. Daily inspections of these units are not required except by state or federal mandates. These SCSRs also do not need to be subjected to the 90-day ASMD evaluation so long as they have not been moved.

To ensure all cache units remain stationary, CSE recommends mine place an easily removable but tamper-proof seal on its storage containers throughout the mine. "Inspection windows for moisture indicators and external temperature indicators may be installed on stationary or mobile storage containers to aid in the inspection of stored units," it added.

It also instructs mines to select well-constructed and internally-padded mobile storage containers for units, as a stronger skeleton around the cache will protect the rescuers from impact and vibration.

These cached SCSRs do not need carry pouches like their regular-use counterparts, as in an emergency situation workers will need to transfer form one pack to another rapidly, the company said. Units on mobile equipment are subject to both daily and ASMD testing.

CSE introduced the first SCSR in 1981, and began marketing the SR-100 in 1989. Considered the first-ever belt wearable, one-hour rated SCSR, the unit remains in use throughout mining as well as other industries such as tunneling and water treatment plants.