Abstract: A highly accurate weighing, feeding and conditioning apparatus for powders and other fine particulate materials is provided. The material is conditioned in a hopper by pulsating inflatable pads within the hopper, or by ultrasonic transmitters mounted on the hopper walls, in apertures in the hopper walls, or on a body at least partially submerged in the fine particulate material. The material is fed by a double auger, one inside the other. In bulk feed mode, both augers rotate at a first, higher speed. In dribble feed mode, only the inner, smaller auger is rotated, at a second, lower speed. This arrangement provides a turn-down ratio of about 500:1. The entire assembly is coupled to a high resolution balance, such as a magnetic force restoration balance, for accurate control of the weight of material fed.