The mining industry requires many kinds of workers. In 2002, 7 out of 10 workers were in construction and extraction, production, or transportation and material-moving occupations.
Mining occupations. The majority of jobs in the mining industry are in construction and extraction occupations. Though most of these jobs can be entered into directly from high school, or after acquiring some experience and on-the-job training in an entry-level position, the increasing sophistication of equipment and machinery used in mining means a higher level of technical skill is now required for many positions.
Underground mining primarily includes three methods-conventional, continuous, and longwall mining. Conventional mining, which is being phased out, is the oldest method, requiring the most workers and procedures. In this method, a strip or “kerf” is cut underneath the ore seam to control the direction in which the ore falls after it has been blasted. Cutting-machine operators use a huge electric chain saw with a cutter from 6 to 15 feet long to cut the kerf. Next, drilling-machine operators drill holes in the ore where the shot firers place explosives. This potentially dangerous work requires workers to follow safety procedures, such as making sure everyone is clear of the area before the explosives are detonated. After the blast, loading-machine operators scoop up the material and dump it into small rubber-tired cars run by shuttle-car operators, who bring the coal or ore to a central location for transportation to the surface.
The continuous mining method eliminates the drilling and blasting operations of conventional mining through the use of a machine called a continuous miner. Traditionally, a continuous-mining machine operator sits or lies in a machine’s cab and operates levers that cut or rip out ore and load it directly onto a conveyor or shuttle car. However, the use of remote-controlled continuous mining machines-which have increased safety considerably-now allows an operator to control the machine from a distance.
In longwall mining, which is similar to continuous mining, longwall-machine operators run large machines with rotating drums that automatically shear ore and load it on a conveyor. At the same time, hydraulic jacks reinforce the roof of the tunnel. As ore is cut, the jacks are hydraulically winched forward, supporting the roof as they move along.
Many other workers are needed to operate safe and efficient underground mines. Before miners are allowed underground, a mine safety inspector checks the work area for such hazards as loose roofs, dangerous gases, and inadequate ventilation. If safety standards are not met, the inspector prohibits the mine from producing until conditions are made safe. Rock-dust machine operators spray the mine walls and floor to hold down dust, which can interfere with breathing.
Roof bolters operate the machines that automatically install roof support bolts to prevent roof cave-ins, the biggest cause of mining injuries. Brattice builders construct doors, walls, and partitions in tunnel passageways to force air into the work areas. Shift bosses, or blue-collar worker supervisors, oversee all operations at the worksite.
In surface mining, most miners operate huge machines that either remove the earth above the ore deposit, or dig and load the ore onto trucks. The number of workers required to operate a surface mine depends on the amount of overburden, or earth, above the ore seam. In many surface mines, the overburden is first drilled and blasted. Overburden stripping operators or dragline operators then scoop the earth away to expose the coal or metal ore. Some draglines are among the largest land machines on earth.
Next, loading-machine operators rip the exposed ore from the seam and dump it into trucks to be driven to the preparation plant. Tractor operators use bulldozers to move earth and ore and to remove boulders or other obstructions. Truckdrivers haul ore to railroad sidings or to preparation plants and transport supplies to mines.
Construction, maintenance, and repair occupations. Other workers, who are not directly involved in the extraction process, work in and around mines and quarries. For example, skilled mechanics are needed to repair and maintain the wide variety of mining machinery, and skilled electricians are needed to check and install electrical wiring. Mechanical and electrical repair work has become increasingly complex, as machinery and other equipment have become computerized. Carpenters construct and maintain benches, bins, and stoppings (barricades to prevent airflow through a tunnel). These workers generally need specialized training to work under the unusual conditions found in mines. Mechanics, for example, may have to repair machines while on their knees, with only their headlamps to illuminate the working area.
Quarrying occupations. Workers at quarries have duties similar to those of miners. Using jackhammers and wedges, rock splitters remove pieces of stone from a rock mass. Dredge operators and dipper tenders operate power-driven dredges, or dipper sticks of dredges, to mine sand, gravel, and other materials from beneath the surfaces of lakes, rivers, and streams. Using power-driven cranes with dragline buckets, dragline operators excavate or move sand, gravel, and other materials.
Processing-plant occupations. Processing plants often are located next to mines or quarries. In these plants, rocks and other impurities are removed from the ore, which is then washed, crushed, sized, or blended to meet buyer specifications. Methods for physically separating the ore from surrounding material also include more complex processes, such as leaching-mixing the ore with chemical solutions or other liquids in order to separate materials. Most processing plants are highly mechanized and require only a few workers for the washing, separating, and crushing operations. Processing-plant supervisors oversee all operations. In plants that are not heavily mechanized, washbox attendants operate equipment that sizes and separates impurities from ore, and shake tenders monitor machinery that further cleans and sizes ore with a vibrating screen. Most jobs in the processing plant are repetitive and, as a result of highly computerized mechanization, are becoming more automated.
Management, business, and financial and professional and related occupations also are important to the mining industry. Administrative workers include top executives, who are responsible for making policy decisions. Staff specialists (such as accountants, attorneys, and market researchers) provide information and advice for policymakers.
Professional and related workers in mining include engineering, scientific, and technical personnel. Environmental scientists and geoscientists search for locations likely to yield coal or mineral ores in sufficient quantity to justify extraction costs. Using sophisticated technologies and equipment, such as the Global Positioning System (GPS)-a satellite system that locates points on the earth using radio signals transmitted by satellites-surveyors help to map areas for mining. Mining and geological engineers examine seams for depth and purity, determine the type of mine to build, and supervise the construction, maintenance, and operation of mines. Mechanical engineers oversee the installation of equipment, such as heat and water systems; electrical engineers oversee the installation and maintenance of electrical equipment; civil engineers oversee the building and construction of minesites, plants, roads, and other infrastructure; safety engineers direct health and safety programs; chemical engineers develop the chemical processes for transforming mined products into consumer goods, such as medications and fertilizers; and materials engineers determine the usefulness of mined ore and also develop processes for transforming the minerals into products.
Environmental engineers play an increasingly important role in mining, given environmental concerns and stringent Federal, State, and local regulations imposed on all operations. Restrictions imposed by environmental regulations make obtaining permits for new mine development projects increasingly difficult. Mine owners and operators face substantial penalties should they fail to abide by current regulations. In addition, both Federal regulations, such as the Surface Mining Control and Reclamation Act (SMCRA), and State laws require that land reclamation be part of the mining process. Reclamation plans usually must be approved by both government officials and local interest groups. When a mining operation is closed, the land must be restored to its premine condition, which can include anything from leveling soil and removing waste to replanting vegetation.
Exploration, mine design, impact assessment, and restoration efforts can depend on computer analysis. In addition, rapid technological advancements, particularly in processing-plant operations, are the result of increased computerization. This has led to a growing reliance on computer professionals, such as systems analysts, computer software engineers, and computer scientists.