During the time of Richard, Earl of Cornwall and King of the Romans, the produce of the tin mines was considerable, and it was in fact largely due to his reputed wealth from this source that he was elected (1257).
The tin workings went on with varying prosperity till the reign of Elizabeth, when she introduced German engineers and workmen, with improved appliances. In her time the tinners of Cornwall were divided into four portions, named from the principal works of that period. Each of these divisions had its steward under the Lord Warden, who kept his court once in every three weeks. The four stannary towns of Cornwall were Helston, Truro, Lostwithiel, and Liskeard; and at Lostwithiel may be seen the remains of the ducal palace; and at Luxulyan the church, in the tower of which the stannary records and charters were formerly preserved.
In Devon the stannary towns were Tavistock, Ashburton, and Chagford, to which Plympton was added in the reign of Edward III., and Lydford was appointed as the stannary prison.
Ordinary justices of the peace had no jurisdiction over the miners in their disputes.
Carew, who was about the court of Queen Elizabeth, has furnished us with a valuable record of the state of the mines before the introduction of new German machinery and methods.
He notices both the stream-works and the lodes, and his opinion was that the deposits in the former were the result of the Deluge.
He then describes the process of shoding, that is of tracing the direction of a vein by fragments found near the surface. The shode pits, which are also called costeening pits, were holes sunk into the ground to no great depth till indications of the lode were reached. The miners next sank pits seven or eight feet deep till they reached the lode itself.
“If they misse the load in one place, they sincke a like shaft” (pit) “in another beyond that, commonly further up the hill, and so a third and a fourth, until they light at last upon it.”
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:—