History of Coal Use

The earliest recognized use of coal took place in the Shenyang area in China around 200 BC, when neolithic inhabitants were carving ornaments from black Lignite, a low grade coal. By the 12th century, China was using coal to produce more pig iron, an early crude form of iron, than Britain ever would annually in the 1700s.

In Europe, the earliest reference to coal is by greek scientist Theophrastus around 200 BC. The Romans in Britain were mining coal wherever they could find it, and using it for grain drying, and heating large public baths. The Romans also used coal to work iron in Somerset.

By the 13th century, coal at ground level in England was exhausted, so mining with the use of deep pits became common. By 1700, 5/6 of the worlds coal came from England. Thanks to the industrial revolution, the need for coal spiked, and there's still serious money in it.

Coal was discovered by the Hopi natives in the american southwest in the 13th century. They used it to cook, heat, make pottery, and carve ornaments from it. Over the next three centuries they extracted 100,000 tons of coal.

How coal is made

The process from which coal is made takes thousands of years. Dying plants in swamp lands deteriorate, and are covered by sediment. Over the years the sediment builds up, increasing pressure on the remains, compressing it, forcing the remaining carbon to accumulate into hard chunks, containing other elements, such as Hydrogen, Sulfur, Oxygen, and Nitrogen.

This process goes through a few stages, but the longer the process, and the more pressure, the better quality the coal. In the early stages, it's known as peat, which can be used as a building material, but other types can be used as fuel.

Then it forms into Lignite or brown coal, which burns longer and contains less moisture and carbon dioxide than peat, but still burns quickly and releases more impurities. The next stage after thousands more years is bituminous coal, containing even less moisture and carbon dioxide, and burns cleaner. This type is the most common, as its cheaper than anthracite, and cleaner than lignite.

Anthracite coal, or black coal, is the highest grade. It has the most carbon, the least impurities, and a higher energy density, which means it burns long and clean. When burned, anthracite produces little to no smoke, so it was used in the boilers of blockade running steamships during the civil war to avoid giving away their position while slipping through blockades.

A grade slightly lower than anthracite known as steam coal is commonly used for steam boilers, as it was well suited to its design. One interesting danger of mining coal is the possibility of a coal seam fire, when coal underground that is exposed due to the process of being mined catches fire due to carelessness, or accidentally while unattended. These fires can last for hundreds of years, for example, in Dudweiler, Germany, a fire that was ignited in 1668 still burns today.