If blasting is necessary for rock excavation, what should be done?

The correct course of action in the scenario of blasting for rock excavation is to ensure the safety of all personnel. The option that emphasizes blasting while the crew is at a safe distance is aligned with safety protocols that dictate that explosive work should occur only when the area is clear of personnel. This helps to prevent accidents and ensure that everyone remains safe during potentially hazardous operations.

Blasting at a safe distance allows for the necessary precautions to be taken and ensures that the crew is not exposed to the immediate dangers associated with explosions, such as flying debris and shockwaves. Rocky terrain often requires careful planning and execution of blasting, and taking the time to ensure safety is crucial to mitigate risks associated with this type of work.

The alternative choices involve unsafe practices, such as blasting while crew members are nearby, which significantly raises the risk of injury, or waiting until after hours without appropriate measures, which can still pose safety risks. Notifying the crew only after the blast might also leave them unprepared for the aftermath of an explosion. Therefore, ensuring a safe distance before detonation is the priority to protect everyone involved in the excavation project.