National Geographic : 1940 Nov
Tin, the Cinderella Metal BY ALICIA O'REARDON OVERBECK LL THE gold and silver mines in the world could stop producing with less disturbance of our personal comfort than a cessation of tin mining would cause! Nevertheless, tin in the popular estimation is a synonym for something cheap and shoddy. Some of our earliest records make tin ap pear as the Cinderella, the Ugly Duckling, of the metal family. Both Isaiah (1: 25) and Ezekiel (22: 18, 20) list it along with dross; and the ancient metallurgists call it Diabolus metallorum, devil among metals. Tin looks somewhat like silver, but as it is far more abundant, and consequently cheaper, it receives a low rating in the popular mind. For example, a bell with a thin, jangling tone is described as "tinny" and one with a delicate, musical peal is described as "sil very." How unfair to tin! Bells, good and bad, are made of copper and tin, and nowa days, at least, contain no silver at all. The word "tin" in its true sense seldom ap pears alone, except in connection with cans and pans; and the metal tin seldom appears in nature except in the company of other metals. For this reason few laymen pause to think that bronze, bell metal, gun metal, Bab bitt metal, type metal, pewter, and a host of others have tin to thank for their existence. U. S. Dependence Upon Tin "The present intense interest in national defense," says the Minerals Yearbook, 1939, of the U. S. Bureau of Mines, "has focused attention on strategic materials in which the United States is deficient. Tin ranks high among such materials . .. "Under normal conditions the United States consumes more than 75,000 tons of tin an nually, or approximately 45 per cent of the total world output. Domestic production never has exceeded 170 tons per annum; thus re quirements have been met by imported metal. "During the last five years 81 per cent of the foreign purchases was obtained from Asia (69 per cent from British Malaya), 18 per cent from Europe, and 1 per cent elsewhere. In the event of war this dependence on for eign sources constitutes a serious threat to national security. . . . Deprived of tin, the industrial power and hence the military effec tiveness of the United States would be im paired seriously." Surprisingly, there are no large tin smelters in the Americas, and the only one of commer cial size in South America is in Argentina. We import refined metal mostly from smelters in the British Empire. Even now our Government officials are pro posing to purchase, under contract with the Bolivian Government, tin ore mined in Bolivia and to build smelters to refine it in this coun try. Such a contract would bring us only half the amount needed. The remainder must be imported as metal from the Far East. Mining High Up in Bolivia The romance of tin mining in Bolivia, part of the old Inca Empire, has touched my own life most closely. If some of the mines of Cornwall lie under the sea (pages 678-9), the mines of Bolivia lie along the roof of the world. They are, in fact, the highest mines in existence, many of them being at an elevation well above 15,000 feet, where only the barrel-chested Bolivian Indian can work with any degree of comfort (page 662). For generations the tin which was mined along with the silver in Bolivia was thrown aside as worthless; and it was not until the last century that its value was recognized. This is understandable when it is considered that the King of Spain was interested only in filling his coffers with precious metals. Soon after Peru was conquered by Pizarro, Potosi Hill, or the Cerro Rico de Potosi, be came the treasure chest of the world. In the early part of the 17th century Potosi was prob ably the largest city of either North or South America, with a population, including slaves, reputed to vary between a quarter and a half million, according to the fancy of the partic ular chronicler. The Spaniards usually mined by shafts, and every ounce of ore was packed to the surface on the backs of sweating Indian captives, who passed in endless procession up and down flimsy, insecure ladders made of notched logs. If a slave dropped dead from overexertion, or slipped from the wet notches of the ladder, another was pushed into his place. What mattered human lives when every day strings of llamas loaded down with bars of silver pushed off for the coast to feed the hun gry maws of the galleons that lay waiting in the roadway of Arica? What did it matter that pirates-although they called themselves privateers-were often lurking outside the harbor for a chance to pounce on the fat prize? Potosi Hill was making history those days.