housing to flow into the body of lssl under the influence of earth 39 s gravity when this method of discharging is used a mixing device according to the invention preferably additionally includes means for mechanically accomplishing such withdrawal of the mixing device and for moving it to a location within the open top of the container for the lssl that is different from the location from which the mixing device was removed an earth moving machine such as a hydraulic excavator is normally preferred as the means for this purpose again primarily for economy because other means of accomplishing such motion would normally require additional capital investment many different variations of the means for causing the mixed finely divided solids and lssl contained within the housing to be discharged into said body of lssl within said container are within the scope of the invention for example an inlet for compressed air or other compressed gas may be provided on the unimmersed part of the housing of the mixing device so that the mixed finely divided solids and lssl contained within the housing can be discharged into said body of lssl within said container without withdrawing the housing from at least partial immersion this could be done quite simply for example by providing a t joint to the inlet for finely divided solids and using the other.