The Material Master bulk bag discharging system provides sealed discharge of fine, dusty powders. A Sure-Seal actuated spout clamping system seals the bag discharge spout for dust-tight operation, while a Flo-Master bag massaging system and rotary valve provide reliable metering of materials during drum filling. A powered Flo-Lock discharge spout closure system quickly halts material flow for partial bag discharging. The drum filling system features a dust-tight actuated filling head, densification system, gain-in-weight scale system, and gravity roller conveyor. The system is designed for Class II, Division II, Group G service.