The mine, located in the Hunter Valley of New South Wales, recently conducted walk-out trials with three CABA models. Enex entered into a forward purchase agreement with Quell supplier, Chubb Fire Equipment, to set a group price arrangement for Enex’s underground mines, with the final decision left to individual sites.

South Bulga safety manager Gary Randle said the Quell gear had offered good visibility, allowed people to communicate, and at 18kg was lightweight. CABA offered approximately 60-90 minutes of compressed air.

Randle said the mine had moved to CABA gear because of limitations with the W65 filter self rescuers and their replacement oxygen rescuers, which would not work under certain level of oxygen. These units protect against up to 1.5% carbon monoxide and some low levels of other toxic gases. They do not, however, protect against irrespirable atmospheres and need oxygen to function. In addition, legislative changes that resulted from the 1994 Moura tragedy require equipment that allows escape through reduced visibility and any irrespirable or irritant atmospheres.

“We wanted compressed air breathing apparatus rather than relying on conditions in the atmosphere,” Randle said.

In a recent paper presented at the NSW health and safety conference in Terrigal, Murray Bird, of the NSW mines rescue service, reviewed the three technologies available to mines for self rescue. These included the filtered self rescuers (FRS), self contained self rescuers (SCSRs), and the CABA gear.

“FRS and SCSR units allow for self-escape only and are just one element of a total escape and emergency system,” Bird said. “CABA is the only unit (of the three discussed) that can provide coverage for all aspects of escape, in-seam intervention and rescue.”

Bird said some advantages of CABA were using the actual unit to test travelling distance throughout a mine; no risk of people taking extra units; eye protection from smoke; and less cost over the 10-year life of the equipment.

Randle said one of the attractions of CABA was the ability to refill the units in-seam, and they are reuseable. If someone was injured they could remain close to a refill station and compressed air supply. Refilling the unit can be achieved without removing the mask, which also reduces possible exposure to gases. South Bulga plans to fit quickfill units at the beginning of the separate air splits, capable of filling 20 twin set units to 300 bar.

The mine has ordered 74 twin set units that will be located underground in working areas. CABA units will be located within approximately 100m of longwall production areas and in development sections just off the main headings. Four CABA cylinders would be located in the tailgate and people working outbye would be serviced by a mobile container with CABA gear.

CABA will not replace filter self rescuers which workers would still fit in the initial event of an emergency. They would then go to the CABA storage units and replace the filter self rescuers with the CABA gear.