The tour that I went on spent 3 hours in the mine. Most of the time we were crouched over in the tunnels and at other times we had to crawl on hands and knees and down rickety old ladders. The mine is at 14,500 feet which, combined with the dust and dank air, made it very physically demanding. Eventhough it was freezing outside, the inside of the mine was very hot, making all of us sweat. The advice that the guide gave us was to chew cocoa leaves and take a few drinks of this 192 proof spirit that the miners drink. I tried both and tried to forget that it was only 9 in the morning.