Long Way Education

By Eman Abdallah Kamel

Eman is a writer and engineer. She is interested in writing about nonrenewable energy and its dangers, among other topics.

Coal mining is the extraction of coal from the ground. Here, you will learn about coal mining methods and their risks to the environment and people.

Coal Mining

Coal mining is the process of extracting coal from the ground or from a mine. Coal has a variety of applications, including industry, electricity generation, and heating. On the other hand, coal is harmful to both humans and the environment.

Let’s explore more about coal mining and its risks.

A Brief History

In Wales, archaeological evidence suggests that coal was used in crematoriums as early as the Bronze Age, approximately 3,000 to 4,000 years ago.

Coal mining in colonial America began in the early 18th century, with commercial mining starting around 1730 in Midlothian, Virginia.

Coal-cutting machines were invented in the 1880s. Before their invention, coal was extracted from the ground using hand tools, such as picks and shovels.

In 1900, about 95% of the world’s commercial energy came from coal, 4% from oil and gas, and less than 1% from hydroelectric power.

With the advent of oil in the 21st century, industrialized nations have become increasingly reliant on it to meet their energy needs, and coal’s share of energy production has declined significantly.

Following the 1973 energy crisis, there was a significant increase in the price of oil, which in turn led to increased demand for coal.

Coal Exploration Procedures

1. Examining the overall topography of the area.
2. Look for coal outcrops on hillsides, roadsides, railroad tracks, or riverbeds. These features suggest the presence of coal-bearing layers.
3. Looking for fossils to determine the age of rocks and the presence of coal in the area.
4. Various coal purity and quality parameters are being examined. Examples include calorific value, moisture content, carbon content, hydrogen content, volatile matter content, and so on.

Coal Mining Methods

According to the U.S. Energy Information Administration, there are two main methods of coal mining.

1. Surface Mining
2. Underground Mining

1. Surface Mining

Surface mining is used when coal is located less than 200 feet below the Earth’s surface. Large machines remove the topsoil and overburden (the rock layer) to expose the coal seams. Mountaintop removal is a type of surface mining in which the tops of mountains are removed to access coal seams. After the coal is extracted, the cleared area is covered with topsoil, which is used to plant grass and trees. 

Did You Know?

Surface mining accounts for approximately 40% of the world’s coal production. Surface mining is also less expensive than underground mining.

Surface Mining Methods

1. Strip Mining: It is a highly mechanized surface mining method, where either a bulldozer or a combination of bulldozers is used to remove the topsoil. The topsoil-to-coal ratio can be as high as 1:12 up to a depth of 30 or 50 feet, or as high as 1:15 when the topsoil is about 90 feet thick.
2. Slice Mining: In this method, the coal seam is divided into strips of suitable thickness, and each strip is worked individually. Common types of strip mining include inclined mining, horizontal mining, and diagonal mining. The strips can be taken in ascending, descending, or mixed order.
3. Horizon Mining: This method is employed in areas where coal seams are folded and fractured. It is a multi-level mining system where the coal seam is accessed via level roads cut into the rock.

2. Underground Mining

Deep mining is used when coal is found more than 200 feet beneath the surface. Some underground mines reach depths of thousands of feet. Miners use elevators to descend the mine shafts and travel in small trains through long tunnels to get the coal. They then use large machines to extract the coal.

Underground Mining Methods

1. Bord and Pillar Method: This method involves excavating a series of narrow, parallel tunnels through the coal seams. Cross-sectional headings link these headings to form pillars that are then used to extract coal, either partially or entirely. The pillars may be square, rectangular, or sometimes rhomboidal in shape, and the galleries surrounding the pillars are always square in cross-section. This method is best suited for extracting coal from flat seams between 1.8 and 3 meters thick at shallow depths.
2. Longwall Method: Longwall mining methods are classified into two types: longwall advancing and longwall retreating. The first method involves extracting a sheet of charcoal to be worked on by pushing the face forward on a wide front, leaving the paths leading to it behind. In longwall mining, the mining front is advanced along the shafts excavated before they are opened. As the front retreats, the depleted mining zone (goaf) is allowed to collapse or fill in, and the shafts within are lost. This method can be used in all geological conditions, but it is particularly well-suited for working in thin coal seams.
3. Shortwall Method: The length of the mining front is much shorter than usual in longwall mining. The short wall was designed to utilize standard room and column equipment, but with simplified engineering and the benefits of a self-advancing hydraulic roof support.

Did You Know?

Natural gases found in coal seams are typically composed of methane (80% to 95%), with smaller amounts of heavier hydrocarbons, nitrogen, and carbon dioxide. Methane is formed as a result of chemical reactions when organic matter is buried at great depths and subjected to heat and pressure, eventually transforming into coal. During the transformation of organic matter into coal, methane and other gases are generated and stored in the coal matrix and in the cracks or pores within the coal seams.

Risks

Coal mining has detrimental effects on both the environment and human health.

1. Environment

• Water Pollution: Surface mining can damage underground aquifers that supply drinking water for domestic use and agricultural purposes. Both surface and underground mining can contaminate nearby water sources with sediment and chemicals. Acid wastewater discharge from mines can leach heavy metals and toxins into streams and groundwater, potentially rendering the water unsafe for drinking.

Did You Know?

Between 1992 and 2002, surface coal mining in the Appalachian Mountains destroyed more than 1,200 miles of streams and deforested approximately 380,000 acres, with valley filling covering more than 83,000 acres and affecting the drainage of nearly 438,000 acres of watershed.

• Air Pollution: There are two main sources of air pollution during the coal production process: methane emissions from mines, which contribute to greenhouse gas pollution, and fine particulate matter emissions, which can cause significant respiratory damage.
• Wildlife Habitats: Coal mining, particularly surface mining, poses a significant threat to wildlife habitats. Logging associated with surface mining can fragment habitats and destroy natural areas.

2. Human health

• Coal mining is one of the most dangerous professions. Coal miners suffer from numerous non-fatal injuries and are susceptible to serious illnesses, most notably black lung disease (pulmonary fibrosis) caused by inhaling coal dust.
• Trucks and trains powered by diesel that transport coal release hazardous chemicals into the Earth’s atmosphere. Serious health risks from these toxic emissions include chronic bronchitis, heart attacks, and reduced lung function.

Sources

• Coal mining methods and their advantages and disadvantages
• There Is No Such Thing as “Clean Coal”
• Basics of Coal Mine Methane

©Eman Abdallah Kamel, 2026

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