Over Dartmoor and the Bodmin moors "the old
men's workings " may be seen; hardly a gully has
not been streamed, every river-bed has been turned
over. The face of the moor is in places welted to
such an extent that it alters the character of the
scene. These workings are now grass-grown; they are
very ancient, and clearly were conducted open to the
sky. As the miners worked up a river-bed they built
a colander behind them of rude blocks of granite,
through which the stream might flow away, and
many a rivulet now runs underground through these
artificial passages.
In dressing the ore the miners broke it with hammers, and then " vanned " it on their broad oak shovels. The wind bore away the valueless dust, leaving the metal behind. By the side of the "goyles," or deep workings, may be found "vanning-steads " where this process was conducted. But with the introduction of machinery the crazing-mill was employed, worked by a waterwheel, in which the ore was passed between two grinding-stones. The washing of the dust which took the place of the dry process was this:—
"The streame, after it hath forsaken the mill, is made to fall by certayne degrees" (steps) "one somewhat distant from another, upon each of which at every descent lyeth a green turfe, three or four foote square and one foote thick. On this the tinner layeth a certayne portion of the sandie tinne, and with his shovell softly tosseth the same to and fro, that through this stirring the water, which runneth over it, may wash away the light earth from the tinne, which, of a heavier substance, lyeth fast to the turfe."
