Everything on Earth revolves around energy. Be it plants, animals or humans. The activities we carry out every day in our families and the tasks we carry out around the world consume energy, which will sooner or later run out. This is why we must conserve the energy resources we have and try to find an alternative resource. Coal is one of the three main fossil fuels. It is made up of living materials, which classifies it as a fossil fuel. It is also classified based on hardness, moisture and heat content. There are several types of coal, but three main types of coal make up the majority of the world's supply. Anthracite is the hardest coal and contains the highest BTU content. Bituminous coal has medium hardness. Lignite is the softest coal. The chemical composition of coal is a mixture of many elements including carbon, hydrogen, oxygen, sulfur and nitrogen. (Illinois Coal Association, 2013) Coal forms on oceans and sea floors. When plants die, they fall to the ocean floor and are pressurized into peat. More and more layers of dead plants cover the peat and dry out, turning into coal. (Illinois Coal Association, 2013) This process is called carbonification, which is when peat is physically and chemically altered. Peat deposits generally form in waterlogged environments. (University of Kentucky, 2012) Coal can be mined in many different ways, but there are two main types that produce the highest percentage of coal; surface and underground mining activities. Nearly 60% of coal is mined from surface mines. Most underground mines are located east of the Mississippi River. About 20% of the coal mined in the United States comes from longwall mines. Longwall mining is underground mining that slices a wall's coal. (National Energy Foundation, ...... middle of document ......//www.nnr.co.za/what-is-nuclear-energy/9. Nuclear Energy Institute. (2013, October 24) Nuclear Energy Costs. Retrieved from http://www.nei.org/Knowledge-Center/Nuclear-Statistics/Costs-Fuel,-Operation,-Waste-Disposal-Life-Cycle10 , October 24). Retrieved from http://www.conserve-energy-future.com/Disadvantages_NuclearEnergy.php11 NC State University (2013, October 25). /a/ncsu.edu/nuclear-energy/politics/foreign12. Business Insider (2013) Retrieved from http://www.businessinsider.com/. 13 reasons to bike to work 2012-1013 Kentucky Coal Association (2007) Retrieved from http://www.coaleducation.org/q&a/10_reasons_why_coal.htm