How should shelter holes be maintained according to safety standards?

Shelter holes should be clear of refuse and other obstructions to ensure they are effective in an emergency situation. Maintaining clear access to these holes is crucial for safety, allowing miners to quickly reach shelter when necessary. Blockages could hinder movement and pose risks during emergencies, so adherence to safety standards emphasizes keeping these areas accessible at all times.

While other options may seem reasonable, they do not align as closely with the core safety requirement for shelter holes. For instance, filling shelter holes with gravel would obstruct emergency access instead of maintaining clear pathways. Marking with flags might help in identification, but it does not address the critical need for clear access. Checking once a month is insufficient; regular monitoring and maintenance are essential to ensure that these areas remain clear and safe for immediate use when needed.