MSHA - Code of Federal Regulations - 30 CFR 56.9310
30 CFR § 56.9310
(a) Prior to chute-pulling, persons who could be affected by the draw
or otherwise exposed to danger shall be warned and given time to clear the
(b) Persons attempting to free chute hangups shall be experienced and
familiar with the task, know the hazards involved, and use the proper tools
to free material.
(c) When broken rock or material is dumped into an empty chute, the
chute shall be equipped with a guard or all persons shall be isolated from
the hazard of flying rock or material.