An apparatus (100) for post-grouting a rock bolt (1) has an elongate sleeve (101) adapted to receive a rock bolt (1) with a first end (1a) thereof extending beyond the sleeve first end (101a) and a second end (1b) thereof extending beyond the sleeve second end (101b). An end fitting (102) is attached to the sleeve second end (101b) and has a central aperture (106, 107) for receiving the rock bolt (1). Grout passages (112) communicate the exterior of the end fitting (102) with the interior of the sleeve (101). A seal means (117) is displaceable between open and closed positions so as to seal the grout passages (112). The seal means (117) is biased towards the closed position at which the grout passages (112) are substantially sealed. Injection of grout into the end fitting (102) via the passages (112) deflects the seal means (117) to the open position enabling flow of grout through the passages (112) and into the sleeve (101).