Field Testing

RANA’s prototype Refuge One Air Centre (called RANA-AIR) was field tested in two underground mines with real miners.

The tests by two Canadian government agencies took place at Pinawa, Ontario in 1993 and the Kidd Creek Mine in Timmins, Ontario, 1994.

Volunteer miners and mine rescue team members were sealed into a prototype Tommyknocker mobile refuge chamber for 24 hours after a simulated mining accident. 

The tests monitored the ability of the unit to maintain a safe atmosphere, the simplicity of its operation under realistic conditions and sought any recommendations from the volunteers for improvements.

The outcomes of the tests are summarized here:

Carbon dioxide levels were maintained:

• Normal CO₂ levels are 350 ppm
• The safe allowable limit of CO₂ is 5,000 ppm
• Test 1 average CO₂ level was 2,300 ppm
• Test 2 CO₂ levels stabilized at 2,500 ppm from a baseline of 700 ppm
• Results of Test 2 also showed the safe allowable limit would have been reached after only 1.5 hrs without an independent supply of breathable air

Oxygen levels were maintained:

• Normal O₂ levels are 20.9%
• O₂ levels must be maintained above 18% to be safe
• Test 1 O₂ levels were between 19.5% and 20.9%
• Test 2 O₂ levels were between 20.2% and 20.6%

Volunteer miners reported high levels of acceptance:

• Controls were simple, easy to use and were called “intuitive”
• Instructions were clear
• Starting the unit, including filling 2 scrubbers with soda lime, took less than 10 minutes
• Unit met or exceeded participants' expectations
• Recommendations for further improvements were incorporated into the commercially available Refuge One Air Centre and Tommyknocker