Mina de São Domingos — Corte do Pinto shaft site Mértola · Beja · Portugal

The Mina de São Domingos has one of the longest-documented histories of any mine in Portugal. Traces of Bronze Age activity have been found at Gaimanitos to the east of the mine, and Phoenician and Carthaginian exploitation of the copper and silver deposits is considered probable. Roman workings between approximately the 1st and 4th centuries AD were extensive, with shaft and gallery systems penetrating to around 20 metres below the Roman drainage level and leaving slag deposits estimated at 650,000 tonnes. The mine fell into disuse after the end of Roman occupation and was not systematically worked again until the 19th century.

The modern period began in June 1854 when Nicolau Biava, an Italian mining engineer, registered a claim at the Câmara Municipal de Mértola. The initial working company, La Sabina, was followed by the transfer of the concession to the English firm Mason and Barry in 1859, under Sir Francis Barry and James Mason. In the years 1859 to 1862, the company constructed 17 kilometres of railway track and four tunnels between the mine and the river port at Pomarão on the Guadiana, initially mule-drawn and steam-locomotive-operated from 1864 onward; thirty-seven locomotives served the line over its life, two of which were built at São Domingos.

During the early years of exploitation Mason and Barry focused on underground workings, but around 1866 falling copper prices forced a change of strategy. From 1867 a large open-cast pit — the corta — was excavated, eventually reaching 120 levels of depth. When open-cast working could go no deeper, underground extraction by the stoping and filling method was resumed, with a vertical shaft sunk to level 150 to serve as the winding access. At its deepest, the combined open-cast and underground workings reached approximately 420 metres. The mine communicated with the surface through three tunnels, with two ending in the valley where machinery and workshops were located and one at the base of the corta. Two principal underground levels existed, with the second reached via perpendicular shafts equipped with ore hoists and worker staircases.

The complex at São Domingos at its height employed around a thousand workers and included housing, a hospital, a theatre, a school, a church, a Protestant cemetery, a cooperative, a central electrical station, and the first private railway in Portugal. The village was among the first in the country to have electric lighting. Around 25 million tonnes of ore were extracted over the life of the mine, with copper as the primary product until the end of the First World War, after which sulphur for the European chemical industry became increasingly important.

The mine was definitively closed in 1966, reportedly in anticipation of legislation that would have made companies financially responsible for environmental remediation. Mason and Barry declared insolvency in 1968. The closure caused significant economic disruption to Corte do Pinto and the surrounding region.

From the early 2000s the site entered a phase of heritage conservation and environmental rehabilitation. In 2004 the Câmara Municipal de Mértola and the Spanish company La Sabina established the Fundação Serrão Martins to conserve and promote the heritage of the mine. The former mining headquarters was converted into a hotel, a small museum and archive was established in a former miner's cottage, and the flooded open-cast corta became an environmental attraction. Santa Bárbara, as patron saint of miners, was and remains the most important festival figure of the community at Corte do Pinto, with her feast day on 4 December celebrated with a procession.

The specific shaft designated Poço Santa Bárbara within the São Domingos complex could not be substantiated in detail from the sources consulted. Its naming likely reflects the veneration of Santa Bárbara by the mining community. The site coordinates place it within the Corte do Pinto area associated with the mine complex.