Coal in 15 pictures

1. A very long history

Starting at the end of the 17^th century in Europe, mining provided the basis for the 19th-century Industrial Revolution. It deeply marked countries' social history and its attendant firedamp explosions were tragic, recurring features in the lives of miners and their families. The Jabin mine (shown here) in France's Loire basin was the site of two successive disasters: in 1871 (70 fatalities) and in 1876 (186 fatalities).

2. Leading fuel for power generation

Coal is the second greatest source of in the world (30%), behind oil, and the leading for generation (40%). While some countries like France and the United Kingdom have closed their last mines, others continue to produce and use coal, including China, the United States, India, Australia, Poland and Germany. The photo shows a power plant in Carling, in the Lorraine region of France.

3. Open-pit mining

Open-pit mines are organized in terraces, rather like a sports stadium. Once the earth above the first has been removed, coal extraction can begin. After the seam has been depleted, miners dig down to the next layer. The photo shows the Morwell mine in Victoria State, Australia, where the fourth layer is being mined.

4. Impressive machinery

Huge excavators extract the coal. Some of them are over 200 meters long and higher than a thirty-story building. The buckets on the excavators can hold up to 300 metric tons of rock.

5. The room-and-pillar method

Coal is very often mined underground. Vertical shafts are dug to reach the deposits. In each coal seam a series of large pillars are placed at regular intervals to support the mine roof. The shafts connect to a grid of huge galleries (10- to 20-square-meter sections) that can extend over dozens of kilometers.

6. The longwall method

Another technique involves using a machine called a that looks like a huge plow. The shearer slowly pushes and cuts through the coalface. It recovers the loosened ore as it advances and lets the roof collapse behind it. This is called caving. However the technique can weaken the subsurface and produce surface disruptions.

7. China, the world's leading producer and consumer

China consumes as much coal as all other countries combined. To meet its development needs, its consumption has grown from 600 million metric tons (Mt) in 1980 to nearly 4 billion Mt in 2014. China has nearly 200 billion Mt of proven reserves but the country's authorities are looking for ways to reduce consumption. Pictured in the photo, the vast mining site of Pingshuo, in Shanxi Province.

8. Decline in American coal production

The United States is the world's second largest coal producer, ahead of India and Australia. But while American coal represented nearly 50% of the energy consumed to produce in 2007, its share had fallen to 37% by 2012. This is attributable to the emergence of production, which boosted the share of gas in American electricity generation from 20% to 30%. In the photo, a mine in Wyoming.

9. German lignite (brown coal)

Although its production has fallen by more than half since 1970, Germany remains the world's largest producer of , ahead of China. This material, which is halfway between peat and coal, produces one fourth of German electricity. In the photo, the Tagebau Garzweiler open-pit lignite mine in North Rhine-Westphalia has become the symbolic target of German environmentalists.

10. Intense global trade

By rail or boat, the largest export flows are from Australia and Russia to China. South Africa is the largest supplier for Europe, which has also imported more American coal since the United States reduced its domestic consumption. Indonesia and Columbia are also major exporters.

11. An issue of potential strategic importance

In Europe, entire regions remain largely dependent on coal mining and the industries that rely on it. The Donbass basin, in Eastern Ukraine, is a critical factor in the conflict between the pro-Russian rebels and the central government in Kiev. The photo shows the Kalinia wells in the Donetsk region. The coal deposits lying just at the surface have given rise to small-scale mines that operate amid uncertain safety conditions.

12. Major environmental impacts

Open-pit mining costs less than underground mining and is therefore more profitable in terms of productivity. Working conditions in these mines are also much safer. However, open-pit mining is less acceptable from an environmental standpoint because it disfigures the landscape and often causes dust pollution. The photo shows the Hunter Valley mine, in New South Wales, Australia

13. Coal, source of pollution

The use of coal in industry causes air pollution, particularly where plants are obsolete. In Beijing (see photo), city residents must sometimes wear masks. The need to improve air quality, more than concern for , is pushing the Chinese authorities to find alternative energy sources.

14. Coal mining still causes fatalities

In China more than a thousand miners died in 2013, according to official statistics. In Turkey, on May 13, 2014, an explosion followed by fire, killed 301 workers in the Soma mine (shown here). The accident provoked outrage among the population and demonstrations calling for improved safety measures.

15. On the way to clean coal?

Reducing emissions and capturing carbon dioxide at the source are the two lines of actions for obtaining cleaner coal. In 2014, Canada launched the first major industrial facility for capturing and storing carbon dioxide in Estevan, Saskatchewan. The SaskPower plant (shown here) recovers carbon dioxide and carries it 200 km away to inject it in oil wells.