Discharge funnel

THE DISCHARGE FUNNELDISCHARGE FUNNEL (EN: discharge cone, emptying funnel; DE: Auslaßtrichter; FR: cone de decharge; ES: cono de descarge; RU: воронка выпуска) is the sequential position of the contact surface between the useful mineral and waste rock during the release of the useful minerals from the certain container under the action of the force of the gravity. They distinguish the three stages of the discharge funnel, namely, the funnels of the downfold, of the introduction, and of the collapse. The loose free-flowing materials flow down from the volumes, which are considered with the non-significant tolerance as the rotational ellipsoids, which are called the release ellipsoids (see the Figure). The particles, which are situated on the surface of these ellipsoids, move along the parabolic trajectories, and arrive to the release hole simultaneously. During the release of the useful mineral, there moves only the determined portion of its mass within the zone, which is called the ellipsoid of the loosening. This zone gradually reaches the region of the influence of the release hole, beyond the boundary of which the particles remain stationary. When the apex of the ellipsoid of the loosening will move beyond the contact plane between the useful minerals and overlying rocks, then the latter rocks start to be displaced. The contact surface acquires the shape of the funnel (the funnel of the downfold), and when this funnel reaches the release hole, then there is started the release of the useful minerals together with the waste rock. In this situation, the discharge funnel is manifested in the form of the funnel of the introduction. When the ellipsoid of the loosening arrives onto the surface of the destructed material, then there is formed on this surface the third stage of the discharge funnel, namely, the funnel of the collapse.