exposed grain surface should look shiny. if it does not, a bridge may have formed.
use a pole or other object to free the bridge from the grain bin roof hatch or from the inside ladder while tied to the ladder securely. do not stand on the grain surface.
carry a long pole when entering grain bins to probe grain for cavities and stabilize the worker in case of sudden grain flow.
use a body harness and safety rope that is securely tied off.
work top to bottom of a vertical grain wall; always staying above the highest point of the wall.
be prepared for the entire grain wall to break free and fall at 