From Ecopedia

About

Coal is an easily combustible sedimentary rock occurring in layered coral beds. Coal is primarily made up of carbon apart from other elements such as hydrocarbons, oxygen, nitrogen, sulphur and hydrogen, which are present in variable proportions.

Appearing in either black or brownish-black, coal is the most abundantly found fossil fuel on earth. Coal is a nonrenewable source of energy taking millions of years to form. Coal is the richest and largest source of electricity generation around the world. Coal accounts for about 40% of the total electricity generated globally. At present in the US, around 49% of the electricity is generated from coal.

Four main types of coal occurring in nature include:

• Anthracite coal, a harder form of coal containing 86-97% of carbon
• Bituminous coal, containing 45-86% carbon.
• Subbituminous coal, containing 35-45% carbon
• Lignite coal, containing 25%-35% carbon

Among the four, anthracite and bituminous types of coal contain most-heat producing energy.

Coal Mining

Extraction of coal from the ground involves coal mining, which is done using two methods:

-Surface mining, used in extracting coal from 200 feet beneath the surface of the earth. Top soil and layers of “overburden” rock are removed to open up the coal seam.

-Underground mining or deep mining involving extracting coal from several hundred feet beneath the earth’s surface. Some underground coal mines are as deep as 1,000 feet.

Environmental Perspective

Coal is the largest anthropogenic source of worldwide carbon dioxide (Co2) emissions. Carbon dioxide emissions from coal usage far exceed the levels of other fossil fuel sources such as petroleum and natural gas.

Effects on the environment

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Combustion

Coal mining and combustion show adverse effects on the global environment. Also, coal mining precipitates hundreds of millions of tons of chemical waste such as fly ash, bottom ash as well as flue gas desulfurization slugde, containing uranium, arsenic, mercury and other heavy metals, which when released contaminate the environment.

Coal combustion produces several harmful emissions:

-Sulfur dioxide (SO2), nitrogen oxides (NOx) and particulates that precipitate environmentally-harmful acid rains

-carbon dioxide (CO2) contributing to greenhouse effect and global warming mercury harming the biological system

The Intergovernmental Panel on Climate Change (IPCC), recognized coal as the largest contributor to anthropogenic increase of carbon dioxide emissions in the atmosphere.

Due to surface coal mining, ground water supplies might be adversely affected. Apart from lowering of water levels and water contamination, mining activities might also lead to significant alteration in water flow directions.

Among various other impacts of coal mining, top soil erosion is a matter of great concern to the environmentalists. Loss of top soil exposes vast areas of infertile wastelands, which are most unsuitable for proper vegetation and wildlife sustenance.

Deadly Explosions

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On April 5th, 2010, a coal mine explosion occurred at the Upper Big Branch mine which is located in West Virginia. This blast killed 26 coal miners, and an additional 3 miners who went in for rescue attempts. It has been said that this blast was the worst in over 40 years of operation.

The Upper Big Branch blast was caused by poor ventilation, which caused a pressure system to build up within the mine.

International Regulations

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Two major UN (United Nations) treaties, UN Framework Convention on Climate Change (UNFCCC) signed in 1992 and Kyoto Protocol accord agreed in 1997 set forth measures to regulate coal mining practices for achieving reduced carbon dioxide emissions from mining activities.

The Kyoto Protocol, in particular, committed the member countries to set binding targets for minimizing carbon dioxide gas emissions by about 5% against the levels recorded in 1990. The protocol set a time period of five years, from 2008 to 2012, to achieve the target level. The rules set for the implementation of the protocol, known as “Marrakesh Accords”, were finalized and adopted at COP7 in the year 2001, in Marrakesh.

Several organizations such as the US Environmental Protection Agency (USEPA) addressed the measurement of coal’s carbon footprint in order to demonstrate the impact of anthropogenic coal combustion on the earth’s environment.

References

http://en.wikipedia.org/wiki/Environmental_effects_of_coal http://tonto.eia.doe.gov/kids/energy.cfm?page=coal_home-basics http://www.carbonfootprint.com/minimisecfp.html http://unfccc.int/kyoto_protocol/items/2830.php