Teacher Background Information: Coal

Teacher Background Information: Coal 6

Teacher Background Information: Coal

Adapted from:

Karla Alejandra Martinez Franco

Introduction

Coal mining has been the greatest source for electric power since the industrial revolution, primarily because of its cheap price and ease of accessibility. Coal has a variety of uses, including electricity generation, steel production and cement manufacturing as a liquid fuel. Currently China is the largest producer and consumer of coal with the United States as a close second. Nevertheless, the future of coal mining is shifting. As new technology, cleaner and cheaper energy options emerge, and new regulations due to concerns over environmental impact are activated, the coal mining industry is in a slow decline.

How is coal formed?

Coal is a fossil fuel, meaning that the production of coal, called coalification, comes from millions of years of decomposition from plants and organic material. Coalification is a multistep process that produces rock (coal) from organic sediment:

1. Organic matter (primarily vegetation) is decomposed and compressed into water-soaked masses called peat.

2. The peat is buried by one of several natural factors such as sea level rise or tectonic movement. Due to the pressure exerted on the peat, water and other impurities are squeezed out of the material transforming the peat into lignite. Lignite, or brown coal, is classified as a low rank coal because it has less carbon content and a lower caloric value than others. Lignite is found close to the surface and is easily mined.

3. As lignite is further compressed by the weight of new overlying rocks it become denser and more compact. The coal goes through a process called maturation. During maturation, as the burial continues, the temperature surrounding the material rises. This change in temperature cooks the coal and burns off chemical constituents like sulfur and converts the coal into the next higher rank: sub-bituminous. As the process continues, the coal is transformed into bituminous coal. Bituminous coal is denser, darker (black), and of higher caloric value than Lignite.

4. As the burial process continues, the coal compacts even more and its density increases. The rise in temperature burns off more impurities and results in coal characterized by high concentrations of free carbon. This is the highest rank of coal called anthracite. Anthracite is highly priced because it burns cleaner and gives off higher ranges of energy than lower ranks (ie. Anthracite has twice the calorie content of lignite). Anthracite is black in color, dense and shiny.

The process in which plants become coal also produces hydrocarbons, specifically methane (CH4) gas.

Different types of coal tend to be mined in different parts of the United States and used for different purposes: lignite, sub-bituminous and bituminous coals are used for electricity generation. Lignite is easily broken up and is mined in the areas of Texas, North Dakota, Montana and the Gulf States; sub-bituminous coal is also a soft coal that is mined in areas of Wyoming and Montana’s Powder River Basin; bituminous is used for steel making processes and also in industrial or municipal steam applications, it is mined in the areas of the Appalachia, the Midwest and West. Anthracite is used in residential, commercial and industrial applications - while its waste products are used for electricity generation. Anthracite is primarily mined in Pennsylvania.

How is coal mined?

Early mining techniques extracted coal where it was most available - near the ground’s surface. With technological advances additional mining methods were developed. Like any industry, how the coal is mined is dependent on factors such as its thickness of the coal seam, rank, potential net recovery, environmental impact, and overall cost of extraction. Currently there are two main mining techniques: underground and surface mining.

Underground Coal Mining.

In underground coal mining there are two main methods: continuous and long-wall. In continuous mining, rooms are cut into the coal seams. These rooms are supported by pillars of coal from the same seam. Machines with large rotating drums and spikes or teeth are used to tear the coal from the seam wall. Afterwards retreat mining is used to go back and collect the pillars for their left over coal. Retreat mining takes place as the miners and machinery move away from a specific area. In long-wall mining, a panel of seam is selected. A rotating mechanical shear moves along the coal seam, in its entirety, in a continuous back and forward motion until all the coal is extracted.

Surface Coal Mining.

Surface mining takes place where the coal is typically found less than 200 feet below ground level. In strip mining the process entails removing chunks of soil and overlying rock located above the coal. This soil and rock is called overburden. The overburden is removed by draglines and shovels. Once the coal is exposed it is drilled or blasted; the coal is removed by shovels or bulldozers. Another type of surface mining is mountain top mining in which the landscape of the mountains is dramatically changed by blasting sides of the mountain to exploit the coal reserves. This type of mining is closely associated with the Appalachian Mountains.

How is electricity produced from coal?

In order for the coal to burn quickly, the material is pulverized into a fine powder, this fine powder in then blown into a combustion chamber where it is burned at high temperatures. Lining the boiler are tubes of water. In the chamber, heat and gas covert the water into steam. This highly pressurized steam is passed through a turbine containing thousands of blades that act like propellers. The steam pushes the blades causing the turbines to rotate at high speeds. After the steam passes the turbines, it is condensed and returned to the boiler. The turbines are connected to generators that consist of carefully wound wire coils. These wire coils are rapidly rotating in a strong magnetic field to create electricity. The high voltage electricity generated (up to 400,000volts) is then transmitted through power grids. When the electricity reaches the consumer it is transformed into safer and manageable voltage of 100-250 volts.

What are the impacts of coal mining in the U.S.?

Economic Impact.

Coal is the largest source of fossil fuel energy in the U.S. and the U.S. holds the largest recoverable reserves of coal in the world. Produced in 25 states (with the majority of coming from Wyoming, West Virginia, Kentucky, Pennsylvania and Texas), over 40% of the electricity generated in the U.S. is from coal. Until recent years, coal was the cheapest energy source. This is changing. Natural gas prices have been reduced because of technological advancements that allow its extraction from domestic shale deposits.

The National Mining Association argues that coal production has tangible benefits in the economy. In 2010, 135,533 were employed in the coal industry. NMA estimates that the average yearly wage for coal miners is approximately $73,000 a year. For each coal industry employee, another 3.5 jobs are created. The U.S. has also benefited from a recent 10% rise in coal exports to Europe and Asia. At the same time, the Energy Information Administration (EIA) reports that some U.S. states prefer to import coal from South America because they find it cheaper than to pay for domestic transportation.

Regulations and Laws

Coal mining is a high stakes industry in respect to the safety of its workers, the economic standpoint, and the environmental impact it produces. Over the last several decades, government involvement has stepped in to provide safer standards for the industry. The most notable include the Clean Air Act and its amendments which provide the National Ambient Air Quality Standards (NAAQS), as well as the regulation of National Emission Standards for Hazardous Air Pollutants (NESHAPs). Throughout the years there have been several attempts to enforce more strict regulations on the pollution caused by the coal industry. For example, the “Cap and Trade” program has been attempted in which companies could have to buy credits for emissions, and caps on pollutants would be issued. The most recent attempt was the Waxman-Markey bill, which was approved by the House in 2009 but then denied by the Senate.

In regards to safety laws, there is the Federal Mine and Safety Act, as well as the Occupational Safety and Health Act, both of which require the U.S. Department of Labor and the Mine Safety and Health Administration (MSHA) to improve and regulate working conditions for miners.

Environmental Impact of Coal Mining

As often as it is the case with nonrenewable energy sources, coal mining has been found to have an adverse impact on the environment. The visible component comes from surface mining and the destruction of the natural landscape. Chemical compounds released in the mining process can contaminate groundwater, rivers and streams. Deforestation is another impact. Although attempts to re-forest areas have been attempted, the soil is often damaged so severely that these attempts fail. Underground mines can collapse, exposing toxic substances that then contaminate water and air. Furthermore, mining coal causes the release of methane gasses which are hazardous not only to the quality of air, but also to the health of miners.

Perhaps one of the biggest consequences of coal mining comes in the form of air pollution. Sulfur can be imbedded into the chemical structure of coal. When the coal is burned, the sulfur is converted into noxious sulfur gasses, causing acid precipitation. The burning of coal also produces carbon dioxide, thus releasing these gasses that contribute to Global Warming. In fact, according to the EIA, coal accounted for 34% of the carbon dioxide emissions by major fuels recorded in 2011. Likewise, nitrogen oxides are also released during the combustion of coal; besides contributing to the Greenhouse effect nitrogen oxide reactions in the ozone layer produce oxidizing agents that directly affect human lungs.

Air pollution also comes in the form of the fly ash that is release from coal driven energy plants. These ashes contain harmful chemicals like silicon, calcium oxides, mercury and arsenic. Thermal pollution can be created when heated water used in coal power plants is released into natural water bodies, affecting the balance of that ecosystem.

Health Impacts of Coal Mining.

It is not hard to imagine the physical threats that miners face on a day-to-day basis. Historically, U.S. coal mining was notorious for causing the most deaths due to the cave-ins, fires, and explosions. While safety laws have been instituted aimed at creating a safer work environment, there are still dangers. According to the Miner Safety and Health Administration (MSHA), there were sixteen coal mining related deaths in the first nine months of 2012.

Pneumoconiosis, also known as “black lung”, is a common ailment of coal miners. One of every ten miners will suffer from various degrees of lung/respiratory related deceases. In addition, some researchers suggest a correlation between the proximity of a community to coal production with health diseases. A 2001 survey in West Virginia found residents who resided in close proximity to the coal production cite suffered greater incidence of cardiovascular, pulmonary, hypertension and diabetes and kidney disease.

Useful Websites:

U.S. Energy Information Administration:

Coal Explained

http://www.eia.gov/energyexplained/index.cfm?page=coal_home

Coal Mining and Transportation

http://www.eia.gov/energyexplained/index.cfm?page=coal_mining

Where Our Coal Comes From

http://www.eia.gov/energyexplained/index.cfm?page=coal_where

Coal Imports and Exports

http://www.eia.gov/energyexplained/index.cfm?page=coal_imports

How Much Coal Is Left

http://www.eia.gov/energyexplained/index.cfm?page=coal_reserves

Use of Coal

http://www.eia.gov/energyexplained/index.cfm?page=coal_use

Prices and Outlook

http://www.eia.gov/energyexplained/index.cfm?page=coal_prices

Coal and the Environment

http://www.eia.gov/energyexplained/index.cfm?page=coal_environment

Teachers’ Domain

http://www.teachersdomain.org/resource/ayv09.sci.life.eco.cleancoal/

U.S. Department of Energy

http://www.fossil.energy.gov/education/energylessons/coal/index.html

World Coal Association (Coal and Electricity)

http://www.worldcoal.org/coal/uses-of-coal/coal-electricity/

Useful Reference

American Coal Council, Fact Sheets. (2009). Coal basics . Retrieved from American Coal Council website: http://www.acci.affiniscape.com/associations/10586/files/coal_basics_8-12-09.pdf

Green Peace International. (2010). Mining impacts. Retrieved from Green Peace International website: http://www.greenpeace.org/international/en/campaigns/climate-change/coal/Mining-impacts/

Hafemeister, D. (2011). Energy and environment chronology. AIP Conference Proceedings, 1401(1), 447-454. doi:10.1063/1.3653869

Hendryx, M., & Ahern, M. M. (2008). Relations Between Health Indicators and Residential Proximity to Coal Mining in West Virginia. Academic Journal of Public Health, 98(4), 669-671. Doi:10.2105/AJPH.2007.113472

Howard, J. (2012, July 09). Appalachia terns on itself. The New York Times . Retrieved from http://www.nytimes.com/2012/07/09/opinion/appalachia-turns-on-itself.html

Laskowski, K. (2010, October 13). [Web log message]. Retrieved from http://www.visionofearth.org/featured-articles/coal-power-pollution-politics-and-profits/

Lofaso, A. (2011). What we owe our coal miners. Harvard Law & Policy Review, 5(1), 87-113.

National Mining Association. (2011). Economic statistics. Retrieved from http://www.nma.org/index/economic-statistics

Office of Indian Energy and Economic Development, Environmental resources for tribal energy development. (n.d.). Coal mining technologies. Retrieved from Tribal Energy and Environmental Information: Clearinghouse website: http://twwic.anl.gov/er/coal/restech/tech/index.cfm

Reynolds, S. J., Johnson, J. K., Kelly, M. M., Morin, P. J., & Carter, C. M. (2007).Exploring geology. (1st ed., pp. 530-531). Boston: McGraw-Hill College.

Stacher, G. B., PStatcher, G. B., Prakash , A., & Sokol, E. (2011). Coal and peat fires: A global perspective . (1st ed., Vol. 1). Boston: Elsevier.

Tarbuck, E. J., & Lutgens, F. K. (2011). Earth: An introduction to physical geology. (10th ed.). Upper Saddle River, NJ: Prentice Hall.

U.S. Department of Energy, Fossil Energy Office of Communications. (2012). A brief history of coal use. Retrieved from website: http://www.fossil.energy.gov/education/energylessons/coal/coal_history.html

U.S. Energy Information Administration , (2012). What is the role of coal in the united states?. Retrieved from Energy in Brief website: http://www.eia.gov/energy_in_brief/role_coal_us.cfm

World Coal Association , Uses of coal (n.d.). Coal and electricity. Retrieved from World Coal Association website: http://www.worldcoal.org/coal/uses-of-coal/coal-electricity/