In a portable unit having a generally horizontal frame, a container normally resting on the frame and pivotally connected at its rear of the frame for tilting upwardly and rearwardly toward a dumped position, the container having a door at its rear for loading and unloading material for opening when the container is in a dumped position, the improvement being a lift-and-tilt mechanism including a linkage pivotally connected at one end to the frame, and with a subframe unit interposed between the container and unit frame to support the container, with an inner end of the subframe unit pivotally connected to the linkage unit at an opposite end, whereby the linkage and subframe units are movable from a nested position substantially flat with the unit frame to a raised position with the linkage unit disposed substantially vertical, and with the subframe unit holding the container in a normally horizontal position, and with the container tiltable to its dumped position; a power-operated unit for moving the linkage