Education: mining
This industry is one of South Africa’s most important and many people depend on it for employment
FOR thousands of years people have been using Earth’s rocks and minerals to make weapons, tools and ornaments. These natural resources are found in the planet’s crust so they’re mostly obtained through mining.
Tin, copper and iron ore extracted from the ground are used to make metals such as bronze, iron and steel. Gold and silver have always been valued for their durability and beauty. Mining also extracts the coal, oil and gas we use to heat our homes and run our cars’ engines.
FORMS OF MINING
One of the most basic forms of mining activities is panning. In certain places precious metals such as gold are found on the surface, washed up near rivers or in stream beds. By rinsing the sand with water in a bucket or using a sifting device you can check whether the sand contains gold or any other metals. Gold is heavier than sand so will sink to the bottom when carefully rinsed with water.
In areas where mineral deposits are deeply embedded in the ground, deep-level or underground mining is used. A mine shaft is sunk vertically into the ground at a seam or vein – a place rich in mineral deposits. Mineworkers are transported down the vertical shaft by a lift deep underground. From the vertical shaft they then dig horizontal shafts to extract the minerals from the seam. Deep-level mining is dangerous. It becomes hot in these shafts and breathing is difficult. Sometimes there are rockfalls or gas explosions.
Open-cast mining is basically large open pits with terraced sides. The top layers of soil are removed and explosives are used to break up the rocks. The ore is then transported by large trucks to plants for processing. Coal and copper are mined this way. Deep pits sometimes contain uranium. Once all the minerals have been extracted the pit is usually filled in with rubble and soil.
Quarrying involves extracting stone, typically from a mountain side. In the past, quarry workers used dynamite, hammers
and wedges to prise rocks from a mountain. Today it’s done with mechanised saws.
Oil platforms extract oil and gas which are found in the seabed deep beneath the ocean. Sometimes oil spills occur during exploration, polluting the seawater and destroying marine life in the process. South Africa’s national oil company, PetroSA, extracts gas near Mossel Bay and processes it into liquid fuel.
Another mining technique used to extract gas or oil from the earth is fracking. This technique involves injecting liquid under high pressure into underground rock formations to create cracks through which gas or crude oil can be directed via a pipeline to wells on the surface.
Most forms of mining alter the surface of our planet in one way or another but certain forms of mining do more damage than others.
LARGEST MINES IN SA
South Africa’s mines produce many of the world’s commodities and have several of the largest reserves of precious minerals. The country has rich deposits of gold, diamonds, platinum, uranium, chrome, vanadium, palladium, coal, ilmenite, iron ore, manganese, nickel, silica, tin, zinc and zirconium.
At 4km deep, AngloGold Ashanti’s gold mine near Mponeng, southwest of Johannesburg, is the deepest mine in the world.
The Big Hole, or Kimberley Mine, is the largest open-cast mine ever dug by hand. The mine is 1,6km in circumference and 214m deep. Although it closed down in 1914 and no longer produces diamonds, the site remains a popular tourist attraction.
The Palabora mine near Phalaborwa, Limpopo, is 800m deep. The mine has been in operation since 1956 and today it’s the only mine in South Africa to produce refined copper. Its annual output is about 60 000 tons of refined copper – enough to provide for most of South Africa’s needs.
Mogalakwena is the largest platinum mine in South Africa. It was established in 1993 near Mokopane in Limpopo and consists of five open pits, Sandsloot, Zwartfontein, Mogalakwena South, Mogalakwena Central and Mogalakwena North, which range in depth from 45-245m.
Venetia Diamond Mine opened in 1992 in the Venetia Limpopo Nature Reserve. This open-cast mine is the largest diamond producer in South Africa and is already 450m deep.
The Sishen mine near Kathu in the Northern Cape is a 400m deep iron ore mine. This open-cast mine has been in operation since 1953. Sishen has among the biggest iron ore reserves in the world. Since it started operations, more than 900 million tons of iron ore have been produced.
Grootegeluk Coal Mine in Limpopo has one of the world’s largest coal beneficiation plants and can process about 8 000 tons of coal an hour. Using conventional trucks and digging methods the mine produces about 18,8 million tons of coal a year.
The Cullinan diamond mine in Gauteng started operations in 1902 and is famous for producing several of the world’s biggest diamonds. Cullinan has delivered more than 750 diamonds of more than 100 carats each. The mine is also the world’s only significant source of blue diamonds. It occupies 39 hectares and is 190m deep.