A slide gate comprising: a frame assembly which defines an opening through which fluid flows; a slide plate movably mounted to the frame assembly for vertical movement relative thereto so as to selectively open and close the opening in the frame assembly; an operating mechanism for vertically moving the slide plate between its open and closed positions so as to regulate fluid flow through the opening in the frame assembly, wherein the operating mechanism comprises a threaded operating stem which is secured to the top of the slide plate and which extends through a threaded operating nut which is rotatably mounted to the frame assembly, and means for rotating the threaded operating nut so as to cause longitudinal movement of the threaded operating stem relative to the threaded operating nut, so as to raise or lower the slide plate, whereby to open or close the opening in the slide gate; and a threaded fall-protection nut disposed on the threaded operating stem in spaced relation to the threaded operating nut and configured to rotate in unison with the threaded operating nut, the threaded operating nut being spaced from a fall-protection stop plate which is connected to the frame assembly.