Mine roof supports

摘要

A roof support unit for a walking frame roof support assembly is provided with a two part goaf shield. One the goaf shield parts is connected, by means of a link, to the roof cap of the unit; the other goaf shield part being connected, by means of a link, to the floor sill of the unit; and the two parts being hinged to one another. At least one of the links is such as to permit the roof cap to be retracted by an amount sufficient to permit the advance of the unit while preventing the hinged connection between the two goaf shield parts moving towards the goaf side of the mine working.