The resources of the subsoil are numerous and present in large quantities; their exploitation, particularly as regards energy minerals, was the basis of the spectacular industrial development of the United States. After having for a long time exploited their extraordinary mining heritage in an almost uncontrolled way, especially after the Second World War the United States, having become the superpower of the Western world, has transformed itself from an eminently producing country into one that is largely importer of countless raw materials, with oil in the first place. The oil “shocks” of the 1970s, at the root of a temporary and serious international energy crisis, led the country to accelerate the development of alternative sources of energy (for example nuclear power) and to encourage the exploitation of the enormous coal deposits, which they had been set aside at the time of the non-rationalized exploitation of oil reserves. The main carboniferous basin, of excellent litantrace, extends for a thousand kilometers on the western side of the Appalachians, from Pennsylvania to Alabama; it follows the central basin, between the middle Mississippi and the lower Ohio, which continues west of the Mississippi, from Texas to Iowa; also in the West, in the Rocky Mountains, various reserves have been ascertained, of which however only a few deposits are exploited. In 1997 the production of this mineral reached 900 million tons, approx. a quarter of the world total, exceeding one million tons in 2006. Lignite production, on the other hand, is more modest. Equally impressive are the national oil resources, whose fields are located in four main states: in Texas (which supplies about one third of total production), in Louisiana, Alaska and California. The United States is the third largest producer in the world, surpassed only by Saudi Arabia and Russia; a dense network of oil pipelines leads the crude oil to numerous refining plants (in 1977 the Alaska oil pipeline came into operation, connecting the fields of Prudhoe Bay, in the Arctic Ocean, to the port of Valdez, on the Pacific, after a path of 1270 km in the inaccessible arctic areas). The refineries operate not only in the coastal centers of the South, East and West but also in the inner cities (among the many oil complexes we should mention those of Carson in California, on the Pacific, after a journey of 1270 km in the inaccessible arctic areas). The refineries operate not only in the coastal centers of the South, East and West but also in the inner cities (among the many oil complexes we should mention those of Carson in California, on the Pacific, after a journey of 1270 km in the inaccessible arctic areas).
According to cheeroutdoor, the refineries operate not only in the coastal centers of the South, East and West but also in the inner cities (among the many oil complexes we should mention those of Carson in California, Baton Rouge in Louisiana, Toledo in Ohio, Philadelphia in Pennsylvania, Houston in Texas etc.). The oil areas are also very rich in natural gas (of which the United States is the second largest producer in the world, behind Russia), mainly in Texas, Louisiana, Oklahoma, New Mexico, Kansas, California, Wyoming, and at the service of which it was built. a very extensive network of gas pipelines. The United States is the world’s leading producer of electrical and thermoelectric energy (2004). Although most of this energy is of thermal origin, water resources are also conspicuous: they are exploited with impressive systems, built on the great rivers of the East and West (which offer greater flow), as well as in those of the central regions (Missouri basin). Often the large water works carried out have modified the natural landscape, giving rise to enormous artificial lakes; Furthermore, many of the basins serve to regulate the river regime and to feed irrigated agriculture. In the subsoil there are also uranium deposits, which feeds the nuclear energy sector. Despite strong opposition from a large part of American public opinion, worried about the dangerousness of the plants, the production of electricity of nuclear origin covers about one fifth of the national energy needs. The main nuclear plants (about a hundred) are located, among other sites, in Canyon, Baxley, Plymouth, Salem, Prescott, Middletown, Waterford etc. As for metal ores, with the only important exception of iron (whose reserves are located in the eastern states, Texas, Missouri, Colorado, Utah, New Mexico, Wyoming and Nevada) the main deposits are variously located in the Rocky Mountains and mainly concern copper (of which the country is among the largest producers, second in the world after Chile; main deposits in Arizona, Utah, New Mexico, Montana) lead (Missouri, Idaho, Utah, Colorado), molybdenum (New Mexico and Colorado, in particular in Climax, where the largest mine in the world is located) silver (Idaho, Montanta, Utah) etc., and of course that gold (South Dakota, Utah, Nevada, Arizona), the whose “fever”, in the nineteenth century, largely contributed to the progressive population of the West. Alaska supplies gold, copper, silver; the bauxite comes from a basin located behind the Gulf of Mexico. Although it is also a great power in the field of metal ores, the United States is implementing a more careful policy of using its resources, also making use of recycled materials, researching new methods of using low-content minerals and resorting on a large scale to ‘import. With regard to non-metallic minerals, natural phosphate deposits are abundant (mostly supplied by Florida), followed by those of potassium salts, sulfur and salt.