Coal has been a valuable natural resource in the United States throughout the country’s history. European settlers began to use coal for heating in the late 1740s and, as energy demands increased, coal production climbed from 9.3 million tons in 1850 to 750 million in 1918. Eventually coal replaced wood as the primary energy source, and by the 1940s, coal was providing up to 75 percent of U.S. energy needs. In the United States, bituminous coal was the first target of the coal mining industry. This changed between 1843 and 1868 when more anthracite began to be mined. Used in iron smelting, this cleaner and smokeless alternative became the preferred fuel in cities. However, limited anthracite resources could not fulfill increasing demand. The production of sub-bi - tuminous coal began to slowly rise, and in 2010 it was greater than bituminous coal produc - tion. Until the 1950s, coal was mined primarily using underground methods. By the 1970s, however, the development of cheaper surface mining proved a viable alternative for the U.S. coal industry. Over the last 10 years, coal production in the United States dropped 37 percent, from about 1.1 billion to about 702 million tons in 2017, and the number of active coal mines also declined. Coal consumption declined as a result of an increased supply of cheaper and cleaner natural gas, the growth of renewable energy sources, and enforced environmental regulations. Coal provided close to 60 percent of U.S. electricity in the mid-1980s, but only about 30 percent in 2017. While there were 606 coal-burning power plants in 2007, only 359 were operating in 2017, with the remainder closed because of aging infrastructure and stiffer environmental guidelines. Coal mining is an industry in transition—new technologies and policies continually to reshape the energy landscape. With increased competition from other sources of energy, a steady decline in the number of coal-fired power plants, and increasing public perception of coal as a dirty fuel, the coal industry faces even more changes.