Abstract: A measuring flask 10 is described for use in a mine shaft assembly. The measuring flask 10 includes a body 12, a discharge opening 25, a door 24, and a pressurised fluid actuated door locking mechanism 40. The body 12 defines a storage chamber having a sloping bottom 22 and the discharge opening 25 is defined in the body 12 adjacent to the sloping bottom 22. The door 24 is displaceable between a closed position in which it closes the discharge opening 25 and an open position in which is permits material to be discharged from the measuring flask 10 through the opening 25. The door locking mechanism 40 is operable to lock the door 24 releasably in its closed position. Instead or in addition to the door locking mechanism 40, the measuring flask 10 has a resilient door retaining arrangement 50 configured to retain the door 24 releasably in its closed position.