Coal mining

It became important in the Industrial Revolution of the 19th and 20th centuries, when it was primarily used to power steam engines, heat buildings and generate electricity.

The most economical form of underground mining is the long wall, which involves using two spinning drums with carbide bits that runs along sections of the coal seam.

Technical and economic feasibility are evaluated based on the following: regional geological conditions; overburden characteristics; coal seam continuity, thickness, structure, quality, and depth; strength of materials above and below the seam for roof and floor conditions; topography, especially altitude and slope; climate; land ownership as it affects the availability of land for mining and access; surface drainage patterns; groundwater conditions; availability of labor and materials; coal purchaser requirements in terms of tonnage, quality, and destination; and capital investment requirements.

For example, some western U.S. coal that occur at depths in excess of 60 m (200 ft) are mined by the open pit methods, due to thickness of the seam 20–25 metres (60–90 feet).

[9] However, there are open pit mining operations working on coal seams up to 300–460 metres (1,000–1,500 feet) below ground level, for instance Tagebau Hambach in Germany.

A ridge of undisturbed natural material 15 to 20 ft (5 to 6 m) wide is often intentionally left at the outer edge of the mined area.

[9] The process is highly controversial for the drastic changes in topography, the practice of creating head-of-hollow-fills, or filling in valleys with mining debris, and for covering streams and disrupting ecosystems.

After the large pillars of coal have been mined away, the mobile roof support's legs shorten and it is withdrawn to a safe area.

[21] In several parts of the world, producers have reached peak coal as some economies shift away from fossil fuels to address climate change.

Piles of coal refuse can have significant negative environmental consequences, including the leaching of iron, manganese, and aluminum residues into waterways and acid mine drainage.

[40] The most fatalities during the 2005–2014 decade were 48 in 2010, the year of the Upper Big Branch Mine disaster in West Virginia, which killed 29 miners.

[43] Build-ups of a hazardous gas are known as damps, possibly from the German word Dampf which means steam or vapor: Noise is also a contributing factor to potential adverse effects on coal miners' health.

For example, a study has found that among surface coal mine operations, dragline equipment produced the loudest sound at a range of 88–112 dBA.

[45] Within longwall sections, stageloaders used to transport coal from the mining face and shearers used for extraction represent some of the highest noise exposures.

[48] Statistical analyses performed by the US Department of Labor's Mine Safety and Health Administration (MSHA) show that between 1990 and 2004, the industry cut the rate of injuries by more than half and fatalities by two-thirds.

[49] One study, though, has suggested that hazards of modern mining are now more accretive with workers facing long-term health impacts, such as sleep deprivation, that build up over time.

Paleontological, cultural, and other historic values may be endangered due to the disruptive activities of blasting, ripping, and excavating coal.

Dust degrades air quality in the immediate area, has an adverse impact on vegetative life, and constitutes health and safety hazards for mine workers and nearby residents.

The soil and rock removed is deposited in nearby valleys, hollows and depressions, resulting in blocked (and contaminated) waterways.

[53][54] Removal of soil and rock overburden covering the coal resource may cause burial and loss of topsoil, exposes parent material, and creates large infertile wastelands.

[53] Top 10 hard and brown coal producers in 2012 were (in million metric tons): China 3,621, United States 922, India 629, Australia 432, Indonesia 410, Russia 351, South Africa 261, Germany 196, Poland 144, and Kazakhstan 122.

Chinese underground mines often experience severe surface subsidence (6–12 meters), negatively impacting farmland because it no longer drains well.

The company has its own 150 km standard-gauge railroad, connecting the mine to its coal-loading terminal at Puerto Bolívar on the Caribbean coast.

In September 2020, the government and mining union agreed a plan to phase out coal by 2049,[86] but this has been criticised by environmentalists as too late to be compatible with the Paris Agreement to limit climate change.

The government pre-engaged to spend 250 million Euro to pay for early retirements, occupational retraining and structural change.

Britain's coalfields are associated with Northumberland and Durham, North and South Wales, Yorkshire, the Scottish Central Belt, Lancashire, Cumbria, the East and West Midlands and Kent.

[120] Almost all onshore coal resources in the UK occur in rocks of the Carboniferous period, some of which extend under the North Sea.

[125] In 2011, former U.S. president Barack Obama said that the U.S. should rely more on cleaner sources of energy that emit lower or no carbon dioxide pollution.

US coal production increasingly comes from strip mines in the western United States, such as from the Powder River Basin in Wyoming and Montana.

On 13 April 2016 the company reported that its revenue had reduced by 17 percent as coal prices fell and that it had lost two billion dollars the previous year.