Abstract: During the process for production of a rubber mass the rubber mass is mixed in a mixing tank (12) by means of mechanical means (34); then, the movement of the mechanical means (34) for mixing of the rubber mass is interrupted; then, with the mechanical mixing means (34) stopped, the tank (12) is opened by displacing a door (18) for shutting of an opening (16) for discharge of the rubber mass from the tank (12), according to an opening trajectory between a position of shutting of the opening (16), towards a position of release of the opening (16); the positions of shutting and release corresponding to the ends of the opening trajectory; then, with the tank (12) open, the movement of the mechanical means (34) for mixing of the rubber mass is restarted when the door (18) is in a predetermined intermediate position of its trajectory between the positions of shutting and release.