Coal mining accident question?

I'm writing a novel, and I want to be accurate, so before I go googling, I thought I'd ask here so I can compare information. If an underground coal mine were to cave in, could some of the miners get out, and how long would the remaining individuals have to be trapped inside before they were declared deceased? Thank you. (this is just a side piece in my story, but it is important to me that it sounds feasible)