The potash mines are among the most highly mechanized of the mineral industry. Access to the buried deposits is gained by vertical shafts. Actual mining is now done to a large extent by continuous miners, machines which bore or rip the potash ore from the face and load it into shuttle cars in one continuous operation. The shuttle cars then transport the ore to conveyor belts which move it to the shafts for hoisting. Working conditions and safety are excellent and have led to high productivity from these mines. The potash ore is refined or processed by fractional crystallation or flotation. These plants remove most of the unwanted sodium chloride and other gangue minerals to produce high-quality potassium chloride or sulfate. After processing, the potash salts are stored in giant bins to await shipment by rail to the major agriculture areas of the United States. The Carlsbad mines produce some 15 million tons of ore a year which, when refined, produces 4 million tons of marketable potassium salts having a K₂O equivalent of 2.5 million tons. [Illustration: (_Courtesy International Minerals & Chemical Corp._) Crunch!... continuous mining machine at work] Uranium mining is the newest major industry in New Mexico. The boom started in 1950 with the discovery of uranium ore west of Grants by a Navajo sheep rancher named Paddy Martinez. This discovery started one of the most extensive exploration and development campaigns in all mining history. By 1957, the area had proved uranium reserves accounting for more than half of the entire reserve of the nation. These discoveries will make this country self-sufficient in this vital atomic energy metal for years to come. Five mills were built that are capable of producing “yellow cake” (almost pure uranium oxide) from uranium ores containing as little as 0.20 per cent U₃O₈. Four mills are located in the Grants area, ranging in capacity from 1500 to 4000 tons a day. The fifth mill, rated at 500 tons a day, is at Shiprock. There are numerous mines, ranging from tiny two-man operations up to great mines producing more than 1000 tons a day. The most prolific producing area is the Ambrosia Lake District north of Grants; most of these mines are underground. Probably the largest single uranium mine, however, is the open-pit Jackpile-Paguate mine of the Anaconda Company on the Laguna Indian Reservation some thirty miles east of Grants. The mine uses electric shovels capable of loading eight cubic yards of ore at a time into large diesel trucks.