Coal Mining: Companies, Methods and Impacts

How coal is extracted

There are two basic coal mining methods, and depth decides between them. According to the U.S. Energy Information Administration, surface mining is used when coal lies less than about 200 feet down, and about two-thirds of US coal comes from surface mines because they cost less to run.

Surface mining

In a surface mine, the soil and rock above the seam (the overburden) are stripped off with draglines, shovels, trucks and dozers, the coal is dug out, and the overburden is put back behind the advancing cut. Area and strip mining work across flat ground, contour mining follows seams around hillsides, and mountaintop removal takes off the top of a ridge to reach several seams at once.

Underground mining

Deeper seams are reached by shafts or sloping tunnels. In room-and-pillar mining, continuous miners cut a grid of rooms and leave pillars of coal standing to hold up the roof. In longwall mining, a shearer moves back and forth along a coal face that can be hundreds of meters wide, under a row of hydraulic roof supports, and the roof behind the supports is allowed to collapse. Longwalls recover more of the seam, while room-and-pillar suits smaller or irregular seams. Most mined coal then goes through a preparation plant that washes out rock and sorts it by size. Our guide to the coal mining process goes through each step.

Thermal coal and coking coal

Coal is classed by rank, which reflects how much heat and pressure it went through as it formed. The EIA lists four ranks: lignite, the softest, at 25 to 35 percent carbon; subbituminous; bituminous; and anthracite, the hardest, at 86 to 97 percent carbon. Most coal is thermal (or steam) coal, burned to make electricity and industrial heat.

Coking coal, also called metallurgical or met coal, is a bituminous coal that softens and fuses when heated without air, turning into coke for blast furnaces that make iron and steel. It sells for more than thermal coal and is mined in a handful of basins, including Queensland’s Bowen Basin, the Elk Valley in British Columbia, the Alberta foothills and central Appalachia. Metallurgical coal was added to the U.S. list of critical minerals in November 2025. Our piece on coal mining in Queensland looks at the largest of those regions, and the hub also profiles CST Coal’s Grande Cache mine in Alberta.

Where US coal is mined

The EIA’s state breakdown, last updated for 2022, shows about 594 million short tons of coal mined in 21 states. Five states produced 73 percent of it:

Source: EIA, Where our coal comes from. Production shares are EIA’s; the mining-method column is a general description.

By region, the West produces the most tonnage, mainly low-sulfur subbituminous coal from Wyoming and Montana, followed by Appalachia and the Interior basin. US output has been falling for years as power plants switch to natural gas and renewables. For the biggest coal companies in the US, the EIA publishes a list of major producers in its Annual Coal Report, and our article on EIA’s top US coal producers sets out that ranking with tonnage and market share.

Coal mining equipment and where it’s used

Underground coal mining relies on a fairly standard set of machines: continuous miners, roof bolters and shuttle cars for room-and-pillar work, and longwall shearers, powered roof supports and armored face conveyors on a longwall. Surface mines use draglines, rope and hydraulic shovels, haul trucks and dozers. Methane monitors, ventilation fans and rock dust are as important as the cutting machines, because coal dust and methane are what cause underground explosions.

Demand for underground coal machinery follows where deep coal is mined. China is the largest market by a wide margin: the International Energy Agency’s Coal 2025 report says China uses about 30 percent more coal than the rest of the world combined, and much of its output comes from underground mines. Australia, the United States, Russia and Poland also run large underground operations. See our roundup of coal mining machines, which covers both the cutting machines and the safety systems around them.

Effects of coal mining

The environmental effects of coal mining start with the land. Surface mines remove whole hillsides, and longwall mining can make the ground above it subside. Exposed rock containing pyrite can produce acid mine drainage, which carries metals into streams for decades if it isn’t treated. Coal seams also release methane, a strong greenhouse gas, both during mining and from abandoned mines. In the US, the Surface Mining Control and Reclamation Act of 1977 requires operators to post bonds and restore mined land.

For miners, the long-standing health risk is coal and silica dust, which causes black lung disease. When a mine closes, the effects shift to the town around it: lost jobs and tax revenue, and land and water that still need cleanup. Our articles on how coal mining affects the environment and what happens when coal mines close cover both.