The documentary opens with a view of the valley. Its peaks, covered with snow, are seen from the entrance of the mine. The image fades into the next frame: the interior of the mine, located at high altitude. The camera follows the miners getting ready for work, putting on their lamps and going into the tunnel. We see them extracting and transporting the material outside, going down to the lowest posts and setting fire to the explosive charges. The camera often closes up on the miners' faces, the true protagonists of the film. In the final scene they go back to daylight, clear the dust off their faces, look at the sun setting over the mountain peaks.