(under subclass 168) Subject matter comprising a barrier means for resisting flow of air from one part of the earth excavation to another part of the excavation.
(1) Note. This subclass includes brattice walls, mine safety doors, etc.
(2) Note. A mere wall of a duct which carries air to, from, or along an excavation or gallery is not included in this subclass.
(3) Note. The partition means often acts as a safety device for protection from fire or explosion or is erected to deflect air toward a particular location in the excavation.
SEE OR SEARCH CLASS
299, Mining or In Situ Disintegration of Hard Material,
12, for processes in which a step is included for preventing injury to a human working in a mine or mining operation.
