S’Argentera constituted one of the principal mining exploitations of the Balearic Islands and the most important one of Eivissa, designed to extract lead and silver. Mining in the area probably commenced in prehistoric times, although the first traces date from the Punic and Roman period. But it is not until the Middle Ages (14th C, specifically) when we have the first documentary sources of the exploitations, with a number of later testimonies.
Part of the ruins of the mine buildings.
The late 18th and the 19th centuries were the final stage in the development of the mines. During the last years of the 19th century and the start of the 20th, S’Argentera suffered a serious crisis caused by the flooding of its galleries. Following a few brief attempts to reactivate the exploitations, the mines were definitively abandoned in the 1950s.
Geologically speaking, the deposit of the S’Argentera mines corresponds to a Pb-Zn mineralisation which was originated by processes of surface alteration of the Lower Jurassic dolomites and marls during a period of intense volcanism undergone by the zone. This process began at the Upper Triassic and continued during Lower Jurassic (210-190 Ma, approximately). This volcanism was due to the separation of the ancient supercontinent of Pangaea into the present-day continents.
The material exploited in the mine was galena, an ore of lead. This mineral tends to contain a certain percentage of silver, and in these cases it is called argentiferous (silver-bearing) galena, which is precisely the type of galena present in S’Argentera, disseminated among the layers of dolomites and marls in the form of veins. Throughout the active life of the mine, over 150,000 tonnes of ore were extracted, with a very variable quality of lead.
Along with the galena there are pyrite, limonite, goethite, barite, quartz and especially calcite, which is mostly present in the numerous karstic cavities in the mother rock, the dolomite. There are also residual amounts of cinnabar, an ore of mercury.
