Mining Sector

Significant Points

* Employment is projected to decline in all sectors except coal mining.
* While many mining jobs can be entered directly from high school, a considerable amount of job training and experience is needed before workers can perform most duties; some employers prefer graduates of high school or postsecondary programs in mining or mine technology.
* Earnings are higher than the average for all industries.

Nature of the Industry

South Africa has been endowed with a wealth of natural resources that have fostered its growth and development. In the past, the discovery of resources such as gold or diamonds has resulted in major population shifts and rapid growth for formerly remote regions of the country.Extraction of these resources and finding new deposits is the work of the mining industry. Mining continues to provide the foundation for local economies in some regions.

Goods and services.

Products of the mining industry generate the majority of energy used in this country, from electricity in homes to fuel in vehicles. Mined resources also serve as inputs for consumer goods and the processes and services provided by nearly all other industries, particularly in agriculture, manufacturing, transportation, utilities, communication, and construction. Uses of mined materials include coal, oil, and gas for energy, copper for wiring, gold for satellites and sophisticated electronic components, stone and gravel for construction of roads and buildings, and a variety of other minerals as ingredients in medicines and household products.

Industry organization.

The mining industry contains five main industry segments, which are defined by the resources they produce: oil and gas extraction, coal mining, metal ore mining, nonmetallic mineral mining and quarrying, and support activities for mining.

The oil and gas extraction segment produces the petroleum and natural gas that heat homes, fuel cars, and power factories. Petroleum products are also the raw materials for plastics, chemicals, medicines, fertilizers, and synthetic fibers. Petroleum, commonly called crude oil or just oil, is a liquid formed underground from the decay of plants and animals over millions of years under extreme heat and pressure. Occasionally, this decaying material becomes trapped under a layer of impermeable rock that prevents it from dispersing and creates a pocket of oil. Similar processes also produce natural gas, which can be found mixed with oil or in separate deposits. Finding and extracting the oil and gas in these pockets is the primary function of this industry segment.

Using a variety of methods, on land and at sea, small crews of specialized workers search for geologic formations that are likely to contain pockets of oil or gas. Sophisticated equipment and advanced computer technology have increased the productivity of exploration. Maps of potential deposits now are made using remote-sensing satellites. Seismic prospecting—a technique based on measuring the time it takes sound waves to travel through underground formations and return to the surface—has revolutionized oil and gas exploration. Computers and advanced software analyze seismic data to provide three-dimensional models of subsurface rock formations. Another method of searching for oil and gas is based on collecting and analyzing core samples of rock, clay, and sand in the earth’s layers.

After scientific exploration studies indicate the possible presence of oil, a well must be drilled to prove oil is there. An oil company selects a well site and installs a derrick—a tower-like steel structure—to support the drilling equipment. A hole is drilled deep into the earth until oil or gas is found, or the company abandons the effort. Similar techniques are employed in offshore drilling, except that the drilling equipment is part of a steel platform that either sits on the ocean floor, or floats on the surface and is anchored to the ocean floor. Advancements in directional or horizontal drilling techniques, which allow increased access to potential reserves, have had a significant impact on drilling capabilities. Drilling begins vertically, but the drill bit can be turned so that drilling can continue at an angle of up to 90 degrees. This technique extends the drill’s reach, enabling it to reach separate pockets of oil or gas. Because constructing new platforms is costly, this technique commonly is employed by offshore drilling operations.

Once the drilling reaches the oil or gas, extraction can begin as natural pressure forces the oil or gas up through the drill hole to the wellhead, where it enters separation and storage tanks. If natural pressure is not great enough to force the oil to the surface, pumps may be used. In some cases, water, steam, or gas may be injected into the oil deposit to improve recovery. The recovered oil is transported to refineries by pipeline, ship, barge, truck, or railroad. Natural gas usually is transported to processing plants by pipeline. While oil refineries may be many thousands of miles away from the producing fields, gas processing plants typically are near the fields, so that impurities—water, sulfur, and natural gas liquids—can be removed before the gas is piped to customers. The oil refining industry is considered a separate industry, and its activities are not covered here, even though many oil companies both extract and refine oil.

The coal mining industry segment produces coal, a fossil fuel that is used primarily for electric power generation and in the production of steel. Like oil, coal is formed over millions of years from plant and animal matter, but unlike oil, coal is a solid, and therefore miners must go into the earth to recover it. Many coal seams are located close to the surface, however, which makes the extraction of this resource easier.

Surface mining of coal typically uses the method known as strip mining, which is usually more cost-effective than underground mining and requires fewer workers to produce the same quantity of coal. In strip mining, workers use huge earthmoving equipment, such as power shovels or draglines, to scoop off the layers of soil and rock covering the coal seam. Once the coal is exposed, it is broken up by using explosives, and then smaller shovels lift it from the ground and load it into trucks. Mining companies are required by Federal, State, and local laws to restore the mined land after surface mining is completed; as a result, the overburden and topsoil are stored after removal so that they can be replaced and native vegetation replanted.

Underground mining is used when the coal deposit lies deep below the surface of the earth. When developing an underground mine, miners first must dig tunnels deep into the earth near the place where the coal is located. Depending on where the coal seam is in relation to the surface, tunnels may be vertical, horizontal, or sloping. Entries are constructed so that miners can get themselves and their equipment to the ore and carry it out, while allowing fresh air to enter the mine. Once dug to the proper depth, a mine’s tunnels interconnect with a network of passageways going in many directions. Using the room-and-pillar method, miners remove sections of the coal as they work the coal seam from the tunnel entrance to the edge of the mine property, leaving columns of coal in place to help support the ceiling together with long steel bolts. This process is then reversed, and the remainder of the ore is extracted, as the miners work their way back out. In the case of longwall mining of coal, self-advancing roof supports, made of hydraulic jacks and metal plates, cover the area being mined. As coal is removed, the entire apparatus advances, allowing the ceiling in the mined area to cave in as the miners work back towards the tunnel entrance. Underground mining does not require as extensive a reclamation process as surface mining; however, mine operators and environmental engineers still must ensure that ground water remains uncontaminated and that abandoned mines do not collapse.

The metal ore mining industry segment covers the extraction of metal ores, primarily gold, silver, iron, copper, lead, and zinc. These naturally occurring minerals have a variety of industrial purposes: gold and silver are primarily used in jewelry and high-end electronics, iron is used to produce steel, copper is the main component of electrical wiring, lead is used in batteries, and zinc is used to coat iron and steel to reduce corrosion and as an alloy in the making of bronze and brass.

Most metals do not exist in concentrated form but rather in small traces in rock called “ore”. Indistinguishable from regular rocks to the untrained eye, some ores that contain only a fraction of a percent of metal are mined. As a result, a massive amount of rock must be extracted from the ground in order to obtain a useable amount of metal. As a result of this, and because metal ores are less common than coal, metal mines can be much larger than coal mines and operate in more extreme environments—while coal mines are rarely more than a few hundred feet underground, gold mines, for example, can be over a mile below the surface.

Like coal mines, metal ore mines are found in both surface and underground varieties, depending on where the ore deposit is located. In addition to strip mining, surface ore mines also use the open-pit mining technique. These mines are huge holes in the ground that are mined by blasting rock from the sides and bottom with explosives, carrying out the broken up material in trucks, and then repeating the process. Open pit mines can grow to be hundreds of feet deep and several miles wide. Underground mining of ore is less common, typically only occurring when rich veins of ore are discovered or mineral prices are high enough to justify the added expense.

A significant amount of processing is needed to convert ore into usable metal. The mining industry includes initial mineral processing and preparation activities that are located together with mines as part of the extraction process. Further processing is classified under the primary metal manufacturing industry.

The nonmetallic mineral mining and quarrying industry segment covers a wide range of mineral extraction. The majority of the industry produces crushed stone, sand, and gravel for use in construction of roads and buildings. Other important minerals produced are clays, primarily for ceramics, water filtration, and cement making; gypsum, the primary material used in wallboard; salt, used in foodstuffs and as an ice remover; phosphate, for use in fertilizers; and sulfur, the main component of sulfuric acid, a major industrial input. Most of these minerals are found in abundance close to the surface, so underground mining is uncommon in this industry segment.

Surface mining for stone is also known as “quarrying”. In quarrying operations, workers use machines to extract the stone. Stone—primarily granite and limestone—is quarried by using explosives to break material off from a massive rock surface. The resulting rocks are crushed further and shipped off for the production of asphalt or concrete. Some high-quality stone, such as marble and certain types of granite, is quarried in large blocks, known as dimension stone, and used as a building material by itself.

The final industry segment is support activities for mining. The activities of this industry are often the same as those of the other industry segments, but the work is done by contract companies that specialize in one aspect of resource extraction. For example, the majority of drilling for new oil wells is done by specialty drilling companies; other support companies specialize in exploration for new resource deposits or operation of offshore oil rigs.

Source: bls.gov, mediaclubsouthafrica.com

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