Fossil fuel embedded energy is still photosynthetic in origin. Terrestrial plants, on the other hand, tended to form coal and methane. Many of the coal fields date to the Carboniferous period of Earth's history. Terrestrial plants also form type III kerogen, a source of natural gas. There is a wide range of organic, or hydrocarbon, compounds in any given fuel mixture. The specific mixture of hydrocarbons gives a fuel its characteristic properties, such as boiling point, melting point, density, viscosity, etc. Some fuels like natural gas, for instance, contain only very low boiling, gaseous components. Others such as gasoline or diesel contain
Colorado Fuel and Iron brand name until 2014 when it was closed. The mill is able to produce rail lengths of up to 480 feet (up from the current 80 feet), lengths currently possible only in a few European plants. Steelworks Museum Colorado Fuel and Iron The Colorado Fuel and Iron Company (CF&I) was a large steel concentration. By 1903, it was mainly owned and controlled by John D. Rockefeller and Jay Gould's financial heirs. While it came to control many plants throughout the country, its main plant was a steel mill on the south side of Pueblo, Colorado and was the city's main