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heated coal may be mixed with the pitch in a liquid condition; or the coal only may be heated and then mixed with the powdered pitch in a suitable apparatus, and the whole brought to a plastic state, preferably by means of superheated steam.

These methods with their various modifications are in use at different localities, and the one best adapted for any given coal is determined by its character, the machinery to be used and the fuel to be produced.

Preissig gives in the following table the different varieties of presses used in briquetting fine coal with bond: