MINE VENTILATION

摘要

A tunnel-forming overcast structure for incorporation in the installation of an overcast construction at the intersection of two intersecting passages in a mine, each passage constituting an airway for flow of air for mine ventilation having an upstream and a downstream mouth at the intersection. The structure includes a pair of generally parallel side walls each having a top and a deck extending from the top of one of the side walls to the top of the other side wall and connected to the side walls. Each side wall comprises a plurality of elongate generally vertically extensible panels extending generally vertically in side-by- side relation. Each panel includes an upper member and a lower member, one of the members having a sliding fit in the other. The lower members are in a relatively non-extensible position with respect to the upper members in the structure and are ultimately extensible for completing walling off of the upstream and downstream mouths of one of the airways. A method of installing the structure is also disclosed.