Patent ID: 6264549
Filing Date: 2001-07-24
Classification: E21F

Abstract:
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, said structure comprising 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 comprising a plurality of elongate generally vertically extensible panels extending generally vertically in side-by-side relation, each panel comprising an upper member and a lower member, one of said members having a sliding fit in the other, the lower members being in a relatively non-extended position with respect to the upper members in the structure and being ultimately extensible for completing walling off at least portions of the upstream and downstream mouths of one of the airways.