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.
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.
Approximately 40% of our coal is derived from opencast operations. Several of these opencast operations have recovery rates of nearly 90%. Coal lying less than 70 metres below the surface is extracted from a progressive series of parallel, long, narrow trenches. Overburden rock and soil lying above the coal seam is scraped and blasted out of the currently mined trench. It is then tipped into the mined void of the previous trench.
The stripping operation is carried out by having the draglines walked with large scraper buckets slung beneath long, crane-type boom arms. The exposed underlying coal seams are drilled and blasted loose and hauled out of the pit by heavy duty trucks. When the coal from all viable seams has been extracted and the spoil of the next parallel trench has been deposited in the void, the rehabilitation process begins. The overburden is flattened, the previously stored top soil is spread over it and the area is seeded with a mixture of grasses to return the landscape to its ecological balance.