A small deposit in Tasmania has produced a few thousand tons of rich ore. Diamond drilling has shown that little ore remains.
Nickel-copper sulphides have been found in connection with a large intrusive of basic igneous rock in the Insizwa Range, South Africa. No payable ore has been found.
Nickel sulphide deposits of unknown importance occur in India and in Southwestern China. Small deposits which were worked when nickel was scarce occur in Italy, Scotland, Germany and Austria.
Deposits of the Garnierite and Lateritic Types.
—About one-third of the surface of the island of New Caledonia is occupied by serpentine, this being the weathered product of basic igneous rock. “The ore, noumeaite or garnierite, occurs as a hydrated silicate of nickel and magnesia and may best be described as an alteration product of the serpentine in which the magnesia and iron have been replaced by nickel. * * * The workable deposits always occur on the saddle of spurs from the main mountain ridge, at elevations of 400 to 2,500 feet, the latter elevation being the more common. * * * The replacement of the serpentine by nickel follows the joints and fractures in the serpentine and the undecomposed blocks and boulders of serpentine are as a rule covered by a shell of ore which has to be picked off.” The ores are hand picked to bring them up to a grade profitable to treat. In the past it has not been considered economical to smelt ore of lower grade than 4.5 per cent. nickel nor to ship ore much below 6.5 per cent.
The ore bodies usually contain under 250,000 tons of ore. The largest mine yet worked produced less than 600,000 metric tons (2,204 lb.) of ore. Probably there still remains as much undeveloped ore as has been mined in the forty years of production,—equivalent to 160,000 tons of nickel. This would be equal to about four years’ output of the Sudbury district at the 1916 rate of production. “There are large bodies of lower-grade ores which it has not yet been found feasible to treat.”
Three large blanket deposits of nickeliferous iron ore occur on elevated plateaus in Cuba. These are typical lateritic (residual) deposits. The average depth of the ore is 15 feet and the combined tonnage of the three deposits is placed at one and one-half to three billion tons. The nickel content ranges from about 0.6 per cent. to 2.1 per cent. and shows progressive enrichment from the top downward. Chromium is also present and shows similar enrichment. The presence of nickel and chromium in the iron ores greatly enhances their value for making special steels.
Iron ore on the island of Seboekoe, lying off the southeast coast of Borneo, contains appreciable amounts of nickel and chromium. At least 300,000,000 tons of ore are contained in the deposit, which is a porous limonite, about 15 feet thick, overlying serpentine.
In the United States, nickel deposits of the garnierite type occur in North Carolina and Oregon. Attempts to mine these ores have never been successful.
Small nickel deposits of the garnierite type occur in Egypt, Germany (Prussian Silesia), Greece, Madagascar, Russia and Spain. Nickeliferous iron ores occur in Greece, and it is thought that chromiferous iron ores on Mindao Island, in the Philippines, may, on further exploration, prove to be nickeliferous.