Mineral deposits containing nickel in quantities that make its extraction economically feasible.Industrial nickel ores are divided into cupronickel sulfide and silicate ores.
The cupronickel sulfide ores contain the following principal minerals: pentlandite, millerite,chalcopyrite, cubanite, pyrrhotine, magnetite, and frequently sperrylite. Deposits of these oresbelong to magmatic formations, which are associated with crystalline shields and ancient platforms.They are located in the lower and outer portions of intrusions of norites, peridotites,gabbrodiabases, and other formations of basic magma. They form beds, lentils and veins of richores, as well as zones of less rich disseminated ores, which are characterized by varying ratios ofpentlandite to copper sulfides and pyrrhotine. Disseminated, brecciated, and massive ores arewidespread. The nickel content in sulfide ores ranges from 0.3 to 4.0 percent and more. The Cu:Niratio varies from 0.5 to 0.8 in low-copper ores and from 2 to 4 in high-copper ores. In addition tonickel and copper, considerable quantities of cobalt, as well as gold, platinum, palladium, rhodium,selenium, tellurium, and sulfur, are extracted from such ores. Deposits of cupronickel ores arefound in the USSR in the region of Noril’sk and in Murmansk Oblast (the Pechengi region), as wellas abroad (in Canada and South Africa).
Silicate nickel ores are friable and claylike formations of the crust of weathering of ultrabasites,containing nickel (usually not less than 1 percent). Ores associated with the crust of weathering ofserpentinites of the areal type contain the nickel minerals kerolite, serpentine, goethite, andasbolane. These nickel ores are usually characterized by a moderate nickel content, but theirreserves are significant. Crusts of weathering of the interstitial, contact-karst, and linear-arealtypes, which are formed under complex geological-tectonic and hydrogeological conditions, areassociated with richer ores. The principal minerals in these ores are garnierite, nepouite, nickelkerolite, and ferrihalloysite. The silicate ores include varieties containing iron, magnesia, silica, andalumina, which are usually blended in fixed proportions for purposes of metallurgical processing.
Nickel ores are not susceptible to mechanical enrichment. The silicate nickel ores contain cobaltwith the Co:Ni ratio of the order of 1:20–1:30. In some deposits, the silicate nickel ores areaccompanied by iron-nickel ores with high proportions of iron (50–60 percent) and Ni (1.0–1.5percent). Nickel deposits of the weathered type are known in the USSR in the middle and southernUrals and in the Ukraine.