dispersion tank 24 drops below a designated point dispersed fiber from the dispersion tank 24 is allowed to cascade via valve 31 to use tank 26 and thereafter from tank 26 via fiber control valve 44 to the suction side of the fan pump 48 the level of tank 26 is maintained by probe 41 within a narrow range such that the flow through control valve 44 is held substantially constant thus the need for fiber feed pumps is eliminated operational sequencing throughout the process and within the various sections and stages is accomplished by known techniques through a conventional system of timers and weight and level detectors which is only partially shown simultaneously with the pre processing of the fiberglass fraction as just described the mineral wool fraction is also pre processed by dispersing cleaning and slurrying in section 12 process water is supplied to the mineral wool cleaning system from the machine water tank 16 via mineral fiber pump 50 the pump 50 is a standard centrifugal pump which delivers or moves water from one tank to another via valve 51 mineral wool is introduced into the pre processing section 12 by placing a bale of mineral wool in the bale opener 52 where it is opened and broken up the partially shredded mineral wool fiber is then fed via a conveyor system 54 to the dispersion tank 56 as seen in fig2 and 2a in.