Workers in this unit group perform tasks in operating material handling equipment not performed by workers classified in the preceding unit groups. Their functions include: operating lifting truck to move and stack goods in warehouse, storeroom or other place; operating dump-truck to transfer bulk materials on construction site, mining area or dumping site; operating self-propelled truck (shuttle-car) to transport minerals in a mine; driving a self-propelled vehicle which carries loads of timber beneath its elevated frame; operating other equipment for handling materials such as bucket and belt conveyors and aerial ropeways.