Iberia (modern Spain and Portugal) was possibly the Roman province richest in mineral ore, containing deposits of gold, silver, copper, tin, lead, iron, and mercury). From its acquisition after the Second Punic War to the Fall of Rome, Iberia continued to produce a significant amount of Roman metals. 
Britannia was also very rich in metals. Gold was mined at Dolaucothi in Wales, copper and tin in Cornwall, and lead in the Pennines, Mendip Hills and Wales. Significant studies have been made on the iron production of Roman Britain; iron use in Europe was intensified by the Romans, and was part of the exchange of ideas between the cultures through Roman occupation. It was the importance placed on iron by the Romans throughout the Empire which completed the shift from the few cultures still using primarily bronze into the Iron Age.
Noricum (modern Austria) was exceedingly rich in gold and iron, Pliny, Strabo, and Ovid all lauded its bountiful deposits. Iron was its main commodity, but alluvial gold was also prospected. By 15 BC, Noricum was officially made a province of the Empire, and the metal trade saw prosperity well into the fifth century AD. Some scholars believe that the art of iron forging was not necessarily created, but well developed in this area and it was the population of Noricum which reminded Romans of the usefulness of iron. For example, of the three forms of iron (wrought iron, steel, and soft), the forms which were exported were of the wrought iron (containing a small percentage of uniformly distributed slag material) and steel (carbonised iron) categories, as pure iron is too soft to function like wrought or steel iron.
Dacia, located in the area of Transylvania, was conquered in 107 AD in order to capture the resources of the region for Rome. The amount of gold that came into Roman possession actually brought down the value of gold. Iron was also of importance to the region. The difference between the mines of Noricum and Dacia was the presence of a slave population as a workforce.