Mineral Potential of Portugal (1998)

3. Historical Overview of Mining in Portugal

The mining of mineral resources in Portugal was initially carried out by the Phoenicians, but was intensely and mainly developed by the Romans.

The first mining operations would have taken place in "gossan" type oxidation zones (for copper, zinc, lead, gold and silver) and gold-bearing placers (Carvalho, 1994). The Romans would later intensely exploit gold and polymetallic sulphide vein deposits. To better comprehend the size of the work involved, one need look no further than Três Minas, to the north of Vila Real, from which approximately 10 million tons of material was extracted; and in Aljustrel (southwest of Beja), mine shafts reached a depth of 120 metres.

Then followed a lengthy break in the mining of mineral resources in Portugal which was only occasionally interrupted, the exploitation of alluvial gold in Adiça near Lisbon during the XII century is one example of this.

From the middle of the last century, coinciding with the start of the industrial revolution, mining once more became an important industry in Portugal, with the first mining concessions being granted in 1836.

By the end of the X1X century, approximately 300 concessions had been awarded, the main substances exploited being polymetallic sulphides (Aljustrel, S. Domingos), tungsten and tin (Panasqueira), and antimony and gold (Valongo/Gondomar).

Exploration Permits for Metallic Substances (1980 to 1997)

At the start of the XX century, there was a marked increase in coal annual production.

The two world wars, particularly the Second World War, led to a great demand for tungsten, which in turn led to increased exploration and exploitation of not only this element but tin as well, as these two elements are generally related spatially and/or structurally. Production of the concentrates of these substances peaked during 1942 at 5700 tons for tungsten, the main producing mines being Panasqueira, Borralha, Argozelo, Montesinho, Vale das Gatas and Ribeira.

The country also possesses important uranium deposits, with approximately 4200 tons of U3O8 produced between 1950 and 1990.

From the start of the fifties but mainly in the eighties, exploration underwent somewhat of a boom in Portugal (Fig. 2 and 3), at first including tungsten and tin in the centre and north of the country and later concentrating to precious metals and base metals, the latter sought principally in the Pyrite Belt in the south, where a remarkable number of mineral masses have been discovered: Moinho (1955), Feitais (1963), Estação (1968), Gavião (1970), Salgadinho (1974), Neves Corvo (1977) and Lagoa Salgada (1992).

The most important of these discoveries, in which the IGM (Geological and Mining Institute) has always played an important role, was the Neves Corvo deposit: since the mine came into operation, Portugal has become the largest producer of copper (1988) and tin (1990) in Europe as well as tungsten from the last operational mine (Panasqueira).

Portugal is also an important producer of ornamental rocks, particularly marble, even at the international level.

Exploration of Mineral Deposits (Situation as of 1/98)

Main Gold Occurrences and Deposits

COMO CITAR ESTA PUBLICAÇÃO (HOW TO CITE THIS PUBLICATION):
Instituto Geológico e Mineiro (1998). Mineral Potential of Portugal.
Versão Online no site do INETI: http://e-Geo.ineti.pt/geociencias/edicoes_online/diversos/potential/indice.htm