Video narration
On your shift, you pass beneath one stretch of roof twenty times. Nothing happens. On the twenty-first pass, it comes down. Think of a wooden prop that creaks and shifts before it breaks. The roof can do something similar—but the change can be hidden above the surface you see. Cracks can spread through the rock, weakening it, while the roof still looks unchanged. Its appearance is not proof that it is safe. What makes the difference is support. Before anyone works under a new section, support must already be in place. It carries the load before you enter, instead of asking your eyes to judge strength. A sag or an unusual sound can warn that the roof is changing. Do not go underneath to investigate. Stay out and report loose roof. The rule is simple: never work under unsupported roof, no matter how solid it looks.