A knife gate or other valve is fitted to the ash silo bottom to permit discharge of ash. Ash flows downward through telescoping interlocking cones which are encapsulated by a fabric/elastomeric dust annulus. The length of the telescoping chute assembly can be controlled to suit the unloading/loading conditions. Dust created in the unloading process is drawn upward between the outside of the telescoping cones and the dust containment annulus by an induced air flow generated by a suction fan located at the top of the dry unloader assembly. Dust laden air is drawn through a bag type pulse jet dust collector. Its bags are periodically blown down using compressed air. The accumulated dust cake falls for collection with the principal ash flow discharging from the telescoping unloading chute.