Mining had begun in the 12th century, perhaps earlier. Gold, found in it's 'native' state, and silver are two metals that are usually regarded as 'precious'. However, I feel it is relevant to mention iron and lead. Iron was valuable in the context of manufacturing weapons, where as lead was often employed in the creation of church roofs.
Precious metals can be found in forests, on the slopes of high peaks when the snow has melted, when water overflows it's banks and strips the surface of the land (occasionally revealing the bare treasure beneath), where the wind has uprooted trees and finally when lightning cracks open rocks with precious metals inside.
In the 12th and 13th centuries there was a big drive of traders and colonisers seeking to make a fortune by discovering ores (especially silver nad gold). These aspirations are reflected by the Alpine occupation of the Harz, the Vosges, the Jura and particularly the Eastern Alps where the working of gold, silver and lead grew in importance between the 11th and 12th century. By the mid 12th century progress had intensified as the new interest in mining meant the subsequent spread to other regions.
Focus was switched mainly to central Europe, north of the Danube in places like Saxony, Bohemia, Silesia and Hungary. Together with greater Austria, the Harz and the Black Forest these regions were supplying the whole of Europe with silver, copper and small quantities of gold.
In the earlier Middle Ages it was apparent that Western Germany was the most important source of non-ferrous metals. The chief mines were to be found in the Harz Mountains. The Rammelsberg mine was opened in the 10th century and quickly became a major source of silver, being productive until the 14th century. The mine encountered problems of drainage but overcame them and was once again recognised as a major source of silver in the 15th century.
The Slovak silver mines were opened up by the Germans in the 13th century. They received their fullest expansion with the arrival of merchant capitalists (most notably the Fuggers, Thurzos and Welsers).
German miners continued to branch out in the 13th century and exploited Transylvania and the Balkan Peninsula, whilst opening up the varied resources of Bosnia and Serbia. Gold, silver and lead was mined in Bosnia and Serbia, especially near Novo Brdo (which became the most active centre of the Balkans.
England on the other hand, had a considerable output of lead during the 12th century. The 'mines of Carlisle' (i.e. of Alston Moor, the borders of Cumberland, Yorkshire and Northumberland) all occur on the Pipe Roll of 1130. The Pipe Roll was formed during the reign of Henry II.
Derbyshire was also an important mine as a result of lead. Lead was mined there and carried to Boston where it would be shipped to London and the Continent.
Silver-bearing ores discovered in Devon were exploited to the max alongside lead ore mines at Somerset, Durham, Cumberland, Shropshire, Flintshire and above all Derbyshire. These mines were increasingly fruitful during the 13th century and a healthy lead export trade developed as a consequence.
Evidence of the thriving mining business in Derbyshire can be found in the time of Edward the Confessor (1483-1546), where the mines of Bakewell, Ashford and Hope yielded £30 besides five wain loads of lead.
Although not as common, gold could be found in England. In 1325 John de Wylwringword was sent down the mines of Devon and Cornwall. His objective was to find gold. He managed to obtain 22dwt. from the Devon mines and then travelled to Exeter where 3dwt. of gold was refined and 2 and a half dwt. of pure gold was yielded. 
On the margin of western civilisation (away from the chief centres of cultural/ economic life), precious metals could still be discovered. Silver-bearing ores were found at Alsace and Paris and Ile-de-France produced riches, albeit from the soil.
A flow of gold from the Muslim countries into Europe enhanced the growth of wealth in addition to the supply of money and materials available for industrial use.
Bohemia, principally Krusny Hory (or Ore Mountains), possessed a mainstay of silver which made it one of the most productive mining areas in Europe towards the close of the Middle Ages.
1460 is a crucial date in the industry because it marks the beginning of The Boom in Mining and Metallurgy. Some leading mines reached their zenith of silver production before the 15th century finished. Schneeberg in Saxony was amongst this number.
It is apparent that from the 12th century right through to the 16th century, the Germans were leaders in mining and metallurgy due to incidents of nature. They capitalised on the misfortunes of other western peoples.
The Germans had a wealth of silver, copper and brass. Their most productive mines were the Erzegebirge (found at Schneeberg, Annaberg and Joachimstal, at Schwaz, at Neasohl in Hungary and at Mansfeld where Luther spent part of his childhood).
Salzmann acknowledges the Germans for their skill which enabled them to excel at mining and recognises their influence on the English.
 Exch. K.R. Accts., 262, no.2