Which of the following should be included in a pre-operational check?

Including warning devices in a pre-operational check is crucial for ensuring the safety and operational readiness of mining equipment or vehicles. Warning devices such as lights, alarms, and signals are essential for alerting operators and surrounding personnel to potential hazards. They play a vital role in enhancing visibility and communication on the job site, thereby reducing the risk of accidents. Proper functioning of these devices helps maintain compliance with safety regulations and reinforces the commitment to a safe working environment.

On the other hand, while checks on license plate, oil changes, and interior cleanliness may be important for overall vehicle maintenance or compliance, they do not directly impact the immediate operational safety of the equipment in the context of mining operations. Therefore, focusing on warning devices is essential in a pre-operational check to ensure all safety measures are in place before work begins.