Coal is a combustible black or brownish-black sedimentary rock composed mostly of carbon and hydrocarbons. Coal is composed primarily of carbon along with variable quantities of other elements, chiefly sulfur, hydrogen, oxygen and nitrogen. It is the most abundant fossil fuel produced in the world. ZENITH is a professional coal crusher and coal mill design and manufacturer in the world. We can supply and design kinds of coal crushers and mills.

Types of Coal
Coal is classified into four main types, or ranks (anthracite, bituminous, subbituminous, and lignite), depending on the amounts and types of carbon it contains and on the amount of heat energy it can produce. The rank of a deposit of coal depends on the pressure and heat acting on the plant debris as it sank deeper and deeper over millions of years. For the most part, the higher ranks of coal contain more heat-producing energy.

Anthracite contains 86-97% carbon, and generally has a heating value slightly higher than bituminous coal.  It accounts for less than 0.5% of the coal mined in the United States. 
Bituminous coal contains 45-86% carbon. Bituminous coal was formed under high heat and pressure. Bituminous coal in the United States is between 100 to 300 million years old. It is the most abundant rank of coal found in the United States, accounting for about half of U.S. coal production. Bituminous coal is used to generate electricity and is an important fuel and raw material for the steel and iron industries. 
Subbituminous coal has a lower heating value than bituminous coal. Subbituminous coal typically contains 35-45% carbon. Most subbituminous coal in the United States is at least 100 million years old. About 46% of the coal produced in the United States is subbituminous.
Lignite is the lowest rank of coal with the lowest energy content.  Lignite coal deposits tend to be relatively young coal deposits that were not subjected to extreme heat or pressure, containing 25%-35% carbon. Lignite is crumbly and has high moisture content. There are 19 lignite mines in the United States, producing about 7% of U.S. coal.
Mining of Coal
Coal miners use giant machines to remove coal from the ground. They use two methods: surface or underground mining. Modern mining methods allow us to easily reach most of our coal reserves. Due to growth in surface mining and improved mining technology, the amount of coal produced by one miner in one hour has more than tripled since 1978.

Surface mining is used to produce most of the coal in the United States because it is less expensive than underground mining. Surface mining can be used when the coal is buried less than 200 feet underground.

In surface mining, giant machines remove the top soil and layers of rock known as "overburden" to expose the coal seam. Once the mining is finished, the dirt and rock are returned to the pit, the topsoil is replaced, and the area is replanted.

Underground mining, sometimes called deep mining, is used when the coal is buried several hundred feet below the surface. Some underground mines are 1,000 feet deep. To remove coal in these underground mines, miners ride elevators down deep mine shafts where they run machines that dig out the coal.

Processing of Coal
After coal comes out of the ground, it typically goes on a conveyor belt to a preparation plant that is located at the mining site. The plant cleans and processes coal to remove other rocks and dirt, ash, sulfur, and unwanted materials, increasing the heating value of the coal.

Coal Crusher, Coal Mill and Coal Pulverizer
Coal powder can improve coal burning efficiency, increase power output and reduce harmful gas emission, etc. As a result, coal mills and coal powder processing technologies are increasingly important in electric power plants, steel plants, cement plants and any other industry using injection type coal furnaces.

There are risks of explosion during coal powder processing, store and transportation. ZENITH, as a professional coal mill and coal crusher manufacturer in China, is committed to provide totally safe coal mills and coal pulverization technologies to global customers.

To this end, we adopt international-leading production technologies to design and manufacture our coal mills and coal crushers. Our years' manufacturing experience further guarantees our coal mill quality. Due to this, our coal mill provides decreased danger, and produced coal powder featuring increased burning efficiency.

ZENITH Machinery
ZENITH is a primary coal mill manufacturer and supplier located in China. In addition to coal mills, we can also provide many other machines, such as Ball mill, Raymond mill, Jaw crusher, Cone crusher, Impact crusher and so on. Highly effective impact fine crushers, concentrators, and steel rolling mills are also available here. These products are welcomed by customers due to their good quality and competitive prices. If you need more information of our crushing machine, mineral processing equipment and rolling mill equipment, please refer to products page, or contact us. We are ready to serve you!