Moving mountains may sound impossible, but material moving machine operators do it all the time, one load of earth at a time. They use machinery to move heavy materials around building sites, warehouses, ships and mines. Material moving machine operators use a variety of equipment in different settings. Most of these operators drive forklifts moving materials around warehouses, storage yards, or worksites. They may operate conveyor belts to pick up merchandise, and move it to and from large warehouses, building sites and vehicles. Many operators work for underground and surface mining companies digging mines to extract coal, ore and other materials. They load material onto shuttles or conveyors running from a mine to the surface. Some operate platforms and cages that raise workers and materials up to elevated construction sites or lower them down into mines and quarries. In construction, these machine operators clear space for buildings with excavators, and operate cranes to load and unload building materials. Cranes are also used at ports to move cargo, and at iron and steel mills. Dredge operators shift large quantities of sand and gravel from the bottom of rivers, lakes and other waterways so that ships and boats can move freely. Safe equipment operation is a top priority in this field; injury and illness rates are higher than most occupations. Workers wear gloves, hardhats, or respirators as needed. Most material moving machine operators work full time sometimes with overnight shifts and overtime is common. Although there are typically no formal education requirements, a high school education may be preferred for some positions, and is often required for crane operators, excavating machine operators, and dredge operators. Some states and cities require licensure for crane operators.