Coal combustion products (CCPs) can play an important role in concrete production.  CCPs are the by-products generated from burning coal in coal-fired power plants. These by-products include:

– fly ash
– bottom ash
– boiler slag
– flue gas de-sulphurisation gypsum
– others types of material such as fluidised bed combustion ash, cenospheres, and scrubber residues

Fly ash can be used to replace or supplement cement in concrete. In the USA, for example, more than half of the concrete produced is blended with fly ash.

Among the most significant environmental benefits of using fly ash over conventional cement is that greenhouse gas (GHG) emissions can be significantly reduced. For every tonne of fly ash used for a tonne of portland cement (the most common type of cement in general use around the world) approximately one tonne of carbon dioxide is prevented from entering the earth’s atmosphere. Fly ash does not require the energy-intensive kilning process required by portland cement.

Using CCPs reduces GHG emissions, reduces the need for landfill space, and eliminates the need to use primary raw materials. Fly ash produces a concrete that is strong and durable, with resistance to corrosion, alkali-aggregate expansion, sulphate and other forms of chemical attack.

Coal combustion products are expected to continue to play a major role in the concrete market. Their use in other building products is also expected to grow as sustainable construction becomes more prominent, and more architects and building owners understand the benefits of using CCPs.

[source:  http://www.worldcoal.org]

Coal reserves are available in almost every country worldwide, with recoverable reserves in around 70.  At current production levels, proven coal reserves are estimated to last 164 years.  In contrast, proven oil and gas reserves are equivalent to around 41 and 67 years respectively.  Over 68% of oil and 67% of gas reserves are concentrated in the Middle East and Russia.  Coal provides over 24% of global primary energy needs and generates 40% of the world’s electricity.

[source:  www.worldcoal.org]

South Africa is one of the seven largest coal-producing and one of the top five coal-exporting countries in the world.

More than a quarter of coal mined in South Africa is exported, most of which leaves the country via Richards Bay.  Coal is South Africa’s third largest source of foreign exchange; platinum being the largest and gold second.  Around 15% of the country’s GDP (2000 estimate) is spent on energy and 77% of that is derived from coal.

In 2004, the coal and lignite mining industry generated a gross income of R39 billion and directly employed 50,000 people.  The Witbank Coalfield accounts for 40% of South Africa’s coal production.

[source:  http://en.wikipedia.org/wiki/Coal_mining]

South Africa produces in excess of 255 million tonnes of coal (2011 estimate) and consumes almost three quarters of that domestically.  Around 77% of South Africa’s energy needs are directly derived from coal and 92% of coal consumed on the African continent is produced in South Africa.

The use of coal in South Africa dates back to the iron-age (300-1880 AD), when charcoal was used to melt iron and copper, but large-scale exploitation of coal did not occur until the mid-19th century.

The largest coal deposits in South Africa are to be found in the Ecca Group, a stratum of the Karoo Supergroup, dating from between 280 and 250 Ma. The Ecca Group is extensive, covering around two thirds of South Africa and contains more than a third of all coal reserves in the Southern Hemisphere.

[source:  http://en.wikipedia.org/wiki/Coal_mining]