Today we had a safety training and our instructor told us about a sad event that happens in British Colombia in 2006. The story was about a simple water sampling from a chamber at the rock waste storage of a mine in BC. There was a technician who took water from the chamber everyday without any problems. Everyday he simply climbed down a short ladder, get into the water stream, took a sample and that was it. But one day he went to the chamber and never came back. His wife reported him missing two days after and the company send another technician to check up on him. The second technician went into the chamber saw his co-worker's body floating in water. He thought he was drawn. Quickly he called 911 and then climbed down the ladder to pull out his body. He never came up again.
Two rescuers came to the site and saw two bodies; they called for help. Then a first rescuer rushed down the ladder and collapsed, his colleague saw her falling down the ladder and rushed to help her, he never came back either. Full investigation was conducted on what happened in that chamber of death.
The answer was, lack of oxygen. The combination of bad air flow, temperature and gas coming out of the rock waste made that chamber a death zone for that time that poor fellows visited the chamber. Measurement showed 2% Oxygen and 7% Carbon Dioxide :0.
For the same of comparison consider this, the air we are breathing contains 21% Oxygen and 0.04% Carbon Dioxide. Those poor fellows were suffocated in less than a minute. The sad part was that after the investigation the measurements showed normal level of O2 and CO2 at the top of the chamber. Which means there was no warning for them when they entered the chamber. They were suffocated the moment they reached at the middle of the ladder. Of course new safety measurements were established and enforced but it took 4 lives to realize simple task of water sampling from not even so deep chamber could be fatal.
