SUMMARY
Sheet mica is essential to the manufacture of a vast variety of electrical equipment, and must, therefore, be classed as one of the important raw materials of the world. The magneto, such a vital factor in modern transport on land, air and sea, depends upon mica for its construction, and mica condensers are indispensable in modern radio equipment.
India, Canada, and the United States are at present the most important mica-producing countries. Deposits of future importance from which production has thus far not been great are known in German East Africa, Brazil, Argentina and the Transvaal; from several other parts of the world more sporadic production is reported.
Unlike the development of many other raw materials the production of mica has not been universally undertaken on a large scale, nor have scientific methods been applied to its extraction. This has been largely due to the irregular nature of the deposits and their scattered position within a district, making considerable investment of capital in mining a particularly hazardous venture. Trading interests have, therefore, played an important part in controlling production and markets.
The British Empire, having within its boundaries a large proportion of the important mica-producing districts, at present dominates the situation politically. British commercial control, threatened by Germany’s leading position in the electrical industry and wide interests in Indian mines at the outbreak of war, is now firmly re-established, and Great Britain has taken the place in the electrical industry formerly held by Germany and Austria.
The United States, the largest consumer of mica among the nations of the world, has relied upon imports to supply a considerable part of the consumption and will probably continue to do so in the future, although steady development of domestic sources of supply may be expected. Brazil offers the most promising foreign field for the development of an independent source of supply for American markets.