How often must the operation of each airlock installed for an entrance at the mine be tested, other than pressure tested?

• A. Every two years
• B. Monthly
• C. At least once per year
• D. Weekly

Answer: (C)

The main concept here is how often the operation of an airlock used at a mine entrance must be tested, aside from pressure testing. Airlocks are critical safety barriers that control ventilation and provide a safe means of entry and exit without compromising the seal of the ventilation system. Regular functional testing confirms that interlocks, door timing, alarms, and emergency release features work correctly and reliably, reducing the risk of doors failing to operate in an emergency or during routine entry.

Annual testing is the appropriate minimum frequency. It ensures that wear, faults, or misalignments are caught and corrected without imposing excessive maintenance on routine operations. Testing every week or month would be unnecessarily frequent for normal operation, and testing only every two years could miss developing faults. Separate pressure testing remains a different requirement, focusing on the airlock’s ability to withstand pressure differences, not its mechanical operation.

So, the required frequency is at least once per year.