What is the limit on the storage of explosives if a job will be delayed for more than 48 hours?

The correct choice regarding the limit on the storage of explosives when a job is delayed for more than 48 hours is to store unused explosives in surface magazines. This approach ensures that explosives are kept in a controlled environment that adheres to safety regulations and minimizes the risk involved in their storage. Surface magazines are specifically designed for the safe storage of explosives, providing a secure containment that is far less hazardous than other methods of storage.

Excessive delays in the use of explosives require adherence to strict regulatory guidelines to prevent accidents or unauthorized access. Therefore, relocating unused explosives to a surface magazine is a precaution that complies with mining safety laws in Queensland. This ensures that explosives remain secure and safely handled until they can be utilized for their intended purpose.

The alternatives suggest methods that do not align with safety practices or are impractical for long-term storage. For instance, storing explosives underground under supervision could pose additional risks due to potential access by unauthorized personnel and the risks associated with underground conditions. Retaining explosives in a designated locker on-site may not provide adequate safety or security compared to proper magazines. The disposal of explosives, while sometimes necessary, is not required simply due to a delay and would not be appropriate unless the explosives are deemed unsafe or unusable.