MANGANESE World resources of manganese may be divided into two classes: manganese ore containing more than 3 5 % manganese ; and man ganiferous ores containing less than 35% manganese. In coun tries where manganese ore production is large and consumption small the second class is of small interest, whereas if the opposite conditions prevail manganiferous ores may be of considerable importance. In modem steel-making practice the trend is toward a greater use of high manganese pig iron (see MANGANESE STEEL) and manganiferous ores are extensively used in blast furnaces. This practice is particularly useful where the production of ferro manganese grade ores is small, as the high manganese in the pig iron results in a higher manganese content of the steel during refining and thus in a saving of expensive ferromanganese. The use of high-manganese iron is common in Germany and Russia, and to a lesser extent in the United States.
The largest resources of manganese ore are in Russia, India, Brazil, Gold Coast, and South Africa. The largest developed de posits are in Russia; the Chiaturi deposit in Georgia (Caucasus) has been estimated to contain 163,000,000 tons of ore, the Niko pol deposit in the Ukraine 90,000,000 tons, and numerous smaller ones 78,000,00o tons, a total of 330,000,00o tons. The deposits
of India are numerous, but no recent estimates on reserves are available. The reserves of each of the other leading sources be sides Russia are probably of the order of io,000,000 to 20,000,000 tons. High grade ores are also known to exist, and are mined to some extent, in several other countries, especially Cuba, the Dutch East Indies, China, Chile, Egypt, the former 'Czechoslovakia, Hun gary, Japan, Malaya, Morocco, and Rumania. The reserves of high grade ore in the U.S. are limited to i,000,000 to 1,5oo,000 tons, but Spiegel grade ores approach 20,000,000 tons, and low grade ores total about 45,000,000 tons, averaging 7% Mn. World production in 1937 was in excess of 6,000,000 tons, but a material proportion of this has gone into stocks. (G. A. Ro.)