Elite South African mine rescue squad risks all to save lives

South Africa's elite Mines Rescue Services are dedicated to saving lives in a country with the deepest mines in the world

Carletonville (South Africa)- In a dark, smoke-filled mine shaft, a group of South African rescue trainees heave and gasp after crawling through a narrow steel pipe -- but commands shouted by an instructor urge them onwards.

"Number four, what is your oxygen reading?" he yells.