Which of the following is not a measure to protect the safety of uranium miners?

The choice indicating "Provide special warning monitors for miners to wear" is not typically considered a direct measure to protect the safety of uranium miners in the same way as the other options. While warning monitors can contribute to a safer environment by alerting miners to hazardous conditions, they do not inherently reduce exposure to hazards such as radon gas or dust, which are significant concerns in uranium mining. Measures that are directly aimed at reducing exposure are typically prioritized over monitoring equipment.

In contrast, closing off unused sections of mines can prevent unauthorized access to potentially dangerous areas, thereby enhancing overall safety. Better ventilation systems are crucial in managing and dissipating harmful airborne contaminants, including radon, thus directly protecting miners' health. Encouraging miners to wear respirators directly mitigates inhalation exposure to toxic dust and gases, which is essential to safeguard their respiratory health.