Exploiting the lithosphere or earth’s crust

Stone age: 1.6 million to 2000 years ago people in SA made stone implements – choppers, hand axes & scrapers.

Iron Age: 2000 – 500 years ago people in SA were mainly farmers – cattle, sheep, goats & planting seeds.

Gold was originally found in riverbeds in Limpopo 1000 years ago & was traded with ivory to China, India & Egypt.

Discovery of gold in Limpopo

Early man

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Earth’s crust as source of materials

Elements are usually found in the form of gases in the atmoshpere and in the form of ores of the various substances, in the Earth’s crust.Ores are mined and then the various elements extracted.

Earth's crust

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Common elements in earth’s crust.

Seldom are these elements in pure state.

Most often they are in the forms of the various ores compounds & minerals i.e. metal oxides, nitrates, carbonates etc.These need to be extracted by chemical means.

Elements from the ground

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Mineral distribution in Southern Africa

Indication of mineral distribution in Southern Africa.Mining is a very important source of income in SA.However, people must not be exploited in this industry.

Gold fom our mine dumps

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Mineral distribution in SABesides these elements, diamonds, platinum & uranium are also mined in these areas.Note how most of the minerals are found in the North & North Eastern parts of SA.

SA gold production has decreased from 68% of world’s gold in 1970 to only 8% in 2009. 5

Mining

Mining iron-ore Mining gold-ore Coal mining

In general, rocks containing the minerals & ores must be extracted from the mines, crushed and then often chemically extracted from the crushed rocks.You can elect to study any one of the following major SA mining industries:Gold, iron, phosphate, coal, diamond, copper, platinum, zinc, chrome, asbestos & manganese.

Gold mining in SA

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Questions that need to be asked about mining in SA.

What is available? Where is it found? How is it found? How are the precious materials recovered & processed?

Platinum Diamonds Gold Coal7

Gold mining

The gold industry has been one of the most important industries in SA since alluvial gold was first found in riverbeds and streams at Langlaagte farm in 1886.

After that, deep, underground mines were started and developed in Gauteng & the Free State.

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Gold bars, nuggets & coins

Gold bars or bullion Gold nuggets

Gold coins – printed by the SA Mint – often to commemorate important occasions.

Quartz, granite & gold in rocks

Gold jewellery

Extracting and producing gold

Making a gold bar9

Processing gold ore.

A very important process in SA mining.10

Old method of gold recovery from ore.

Redox reaction:

4Au + 8Na(CN)2 + 2H2O + O2 → 4NaAu(CN)2 + 4NaOH

Recovery by precipitation method:

Zn + 2NaAu(CN)2 → 2Au + Zn (CN)2 + 2NaCN

These days, mines use activated carbon smelting.

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PGMs (Platinum group metals)

SA produces 94% of the world’s Pt – mainly in the Rustenburg area. Pt is used for jewellery, motor vehicle exhausts & for technology.

PGMs in SA

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Pollution

Dust from mine dumpsAir pollution - chemical processing

Open-pit mining Acid water pollution 13

Pollution

Air pollution from burning coal for the generation of electrical power in SA.

The burning of fossil fuels – coal, oil, petrol & gas, releases incredible amounts of greenhouse gases into the atmosphere & many scientists believe this will lead to global warming.

Pollution from mining14

Research pollution in SA

Pollution is already a problem in South Africa and it is set to become an even bigger problem – unless we seriously do something about it – NOW!

Research and write an essay on current pollution and possible future pollution and its effect in our country.

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