First, I have a suggestion for anyone tempted to watch this tepid disaster film. Since every one of the numerous flashbacks is nothing more than a time filler, whenever the screen blurs for a flashback immediately hit the fast forward button. This is how bad it gets, the caverns look fake, the "disasters" are about as scary as a basket of bunnies, and the caverns are miraculously lighted by who knows what, even though they should be in total darkness. The only redeeming factor is a typical smarmy performance from Ray Milland, and Susan Sullivan is effective "eye candy" in tight slacks. One other thing, caves do not cave in, mines cave in. Perhaps this should be called "Mine Cave-In"? - MERK