Geologic Features
The principal cobalt minerals are smaltite (cobalt arsenide), cobaltite (cobalt-arsenic sulphide), and linnæite (cobalt-nickel sulphide). Under weathering conditions these minerals oxidize readily to form asbolite, a mixture of cobalt and manganese oxides, and the pink arsenate, erythrite or "cobalt bloom."
Cobalt minerals are found principally in small quantities disseminated through ores of silver, nickel, and copper. The production of Canada is obtained mainly as a by-product of the silver ores of the Cobalt district (described on pp. 234-235), and smaller amounts are recovered from the Sudbury nickel ores (pp. 180-182). The cobalt of Belgian Congo is obtained from rich oxidized copper ores which impregnate folded sediments (p. 205).
MERCURY (QUICKSILVER) ORES
Economic Features
Uses of mercury are characterized by their wide variety and their application to very many different phases of modern industry; they will be named here in general order of decreasing importance. About one-third of the mercury consumed in this country goes into the manufacture of drugs and chemicals, such as corrosive sublimate, calomel, and glacial acetic acid. Mercury fulminate is used as a detonator for high explosives and to some extent for small-arms ammunition—a use which was exceedingly important during the war, but is probably of minor consequence in normal times. Mercuric sulphide forms the brilliant red pigment, vermilion, and mercuric oxide is becoming increasingly important in anti-fouling marine paint for ship-bottoms. Either as the metal or the oxide, mercury is employed in the manufacture of electrical apparatus (batteries, electrolyzers, rectifiers, etc.), and in the making of thermostats, gas governors, automatic sprinklers, and other mechanical appliances. Mercuric nitrate is used in the fabrication of felt hats from rabbits' fur. In the extraction of gold and silver from their ores by amalgamation, large amounts of metallic mercury have been utilized, but of late years the wide application of the cyanide process has decreased this use. Minor uses include the making of certain compounds for preventing boiler-scale, of cosmetics, and of dental amalgam.
The ores of mercury vary greatly in grade. Spanish ores yield an average in the neighborhood of 7 per cent, Italian ores 0.9 per cent, and Austrian ores 0.65 per cent of metallic mercury. In the United States the ores of California yield about 0.4 per cent and those of Texas range from about 0.5 to 4 per cent. In almost all cases the ores are treated in the immediate vicinity of the mines, and fairly pure metal is obtained by a process of sublimation and condensation. This is usually marketed in iron bottles or flasks containing 75 pounds each.
The large producers of mercury are, in order of normal importance, Spain, Italy, Austria, and United States. Mexico, Russia, and all other countries produce somewhat less than 5 per cent of the world's total.
The largest quicksilver mines of the world are those of Almaden in central Spain, which are owned and operated by the Spanish government. This government, after reserving a small amount for domestic use, sells all the balance of the production through the Rothschilds of London. In addition British capital controls some smaller mines in northern Spain. England thus largely controls the European commercial situation in this commodity, and London is the world's great quicksilver market, where prices are fixed and whence supplies go to all corners of the globe. Reserves of the Almaden ore bodies are very large. Sufficient ore is reported to have been developed to insure a future production of at least 40,000 metric tons—an amount equivalent to the entire world requirements at pre-war rates of consumption for 100 years.
The mercury deposits of the Monte Amiata district of central Italy were in large part dominated by German capital, but during the war were seized by the Italian government. The mines of Idria, Austria-Hungary, were owned by the Austrian government and their ultimate control is at present uncertain. Reserves are very large, being estimated at about one-half those of Almaden. Although England has had a considerable control over the prices and the market for mercury, the Italian and Austrian deposits have provided a sufficient amount to prevent any absolute monopoly. English interests have now secured control of the Italian production, and it is expected that they will also control the Austrian production—thus giving England control of something over three-fourths of the world's mercury.
In the United States about two-thirds of the mercury is produced in the Coast Range district of California, and most of the remainder in the Terlingua district of Texas. Smaller quantities come from Nevada, Oregon, and a few other states. The output before the war was normally slightly in excess of domestic demand and some mercury was exported to various countries. Due to the exhaustion of the richer and more easily worked deposits, however, production was declining. During the war, with increased demands and higher prices, production was stimulated, the United States became the largest mercury-producing country in the world, and large quantities were exported to help meet the military needs of England and France.
With the end of war prices and with high costs of labor and supplies, production in the United States has again declined. Many of the mines have passed their greatest yield, and though discovery of new ore bodies might revive the industry, production is probably on the down grade. Future needs of this country will probably in some part be met by imports from Spain, Italy, and Austria, where the deposits are richer and labor is cheaper. This situation has caused much agitation for a tariff on imports. The present tariff of 10 per cent is not sufficient to keep out foreign mercury.
Outside of the United States large changes in distribution of production of quicksilver are not expected for some time. The reserves of the European producers are all large and are ample to sustain present output for a considerable number of years. It is reported that there will be a resumption of mining in the once very productive Huancavelica District of Peru and in Asia Minor, and with restoration of political order there may be an increase in output from Mexico and Russia,—but these districts will be subordinate factors in the world situation. On geologic grounds, new areas of mercury ores may be looked for in regions of recent volcanic activity, such as the east coast of Asia, some islands of Oceania, the shores of the Mediterranean, and the Cordilleras of North and South America,—but no such areas which are likely to be producers on a large scale are now known.