Mining provides the mineral and energy resources for society, including coal, metallic ores, bauxite, phosphates, and salt, as well as the basic building products such as gravel, limestone, and stone that are essential to the nation’s highways, power plants, bridges, and building foundations. Mining engineers are seeking ways to extract essential raw materials without causing undue disturbance to the environment, as well as to prevent pollution and reclaim land mined in the past.