Equipment must not be operated underground if the external temperature exceeds what degree?

The correct choice indicates that equipment must not be operated underground if the external temperature exceeds 150°C. This regulation is grounded in safety protocols that are designed to protect workers and equipment in mining operations, especially in underground environments where the potential for hazardous conditions can be elevated.

Operating equipment at such high temperatures poses significant risks, including equipment malfunction, increased wear and tear, and the potential for accidents or fires. Exceeding a temperature threshold like 150°C is particularly concerning because it may lead to a breakdown of machinery components, which can pose serious risks to operator safety and overall mining operations.

Understanding these temperature limits is crucial for compliance with Queensland mining laws, which emphasize the protection of workers and the importance of maintaining a safe working environment. This safety measure is a part of the broader regulatory framework that seeks to minimize hazards associated with the mining industry.