For at least two thousand years the metallic mineral wealth of Britain—its tin, copper, lead, iron, silver and gold—has been diligently, if intermittently, sought by merchant and manufacturer, by statesman and speculator, yet only in the last two centuries have soundly-based conceptions of the origin of metalliferous deposits been clearly postulated and widely accepted. Systematic prospecting, surveying and exploitation of the major deposits has been the work of an even shorter period of time. In the immediately preceding centuries practice and theory alike were curious concoctions of practical commonsense, specious medieval theory and spurious alchemical notions—in the words of an eminent modern authority:
A spreading structure supported by fables, a structure top heavy with philosophical reasoning directed towards supporting prior authorities and contemporary religious dogma.
During the sixteenth and seventeenth centuries important and wide-reaching changes took place in the geographical distribution and the intensity of metalliferous mining in the British Isles. From a predominantly surface operation at the beginning of the Tudor Age, metalliferous mining had become a largely subterranean activity by the end of the Stuart era. This led, in virtually all parts of the two islands, to a modified, if not completely transformed, mining technology. During a century of transition, between approximately 1540 and 1640, much of the art of underground mining was learned by the miners of Cornwall and Devon, the High Peak, Alston Moor and other mining districts, an art which was to come to full flower in the nineteenth century and lead to the exodus of the “Cousin Jacks” to Michigan and Nevada, Broken Hill, Iron Knob and a hundred other mining districts in the Americas, Africa and Australasia, where experienced hard rock miners were in high demand.