CHANGES IN PRACTICE
From the nature of mica deposits there has been little encouragement for the application of any but rather crude and simple methods of mining. These methods proved sufficient as long as there remained new and easily accessible deposits. There is at present a tendency in India, Canada, and the United States to apply more scientific methods to exploration and extraction, where the exhaustion of the easily worked deposits is threatened.
Sorting, cleaning, grading, trimming and cutting of mica for the market are all essentially hand processes, and from the nature of the product will continue to be. For this reason producing localities possessing abundant cheap labor have a distinct advantage over those where labor is high and scarce. In one important direction attempts have been made to apply a mechanical device to a process which has always required hand labor. This is in the manufacture of mica splittings, widely used in the manufacture of built-up mica. These inventions have not yet been demonstrated as commercially successful on a broad scale.
Mica is being used to an increasing extent for electrical purposes. The war created a large demand, particularly for the better grades of material for the manufacture of magnetos and radio condensers and spark plugs, and many of these uses will continue to require much mica. The use of mica for glazing purposes, however, particularly in the fronts of stoves, is diminishing. This is due to the decreasing manufacture of the type of stove in which mica is used.