It is important to keep up the appearance that this is a normal operation, and so he descends to the vault to perform his next scheduled duty: inspect what used to be the main drift. The vault is filled with a fog of rock dust around which his windpipe clenches like a fist grabbing a rope. His acetylene lamp only makes the dust glow, giving him a visibility of perhaps six inches. All he can see is the bullion right in front of his face, which still glimmers beneath a film of dust and smoke. The shock wave has deranged his formerly neat stacks of crates and bricks and turned the entire hoard into a rude mound that is still shedding avalanches, seeking its angle of repose. A 75-kilogram gold brick slides down the pile like a runaway boxcar, emerging suddenly from the cloud of dust, and he jumps out of its way. Bits of rock are still sifting down from the crazed ceiling and plinking against his helmet.