Closed shaft site within the Minas de Aljustrel polymetallic sulphide complex, part of a mine first designated a monument in 1982 and now encompassed by the Parque Mineiro de Aljustrel.
The Minas de Aljustrel form one of the most significant polymetallic sulphide mining complexes in the Iberian Pyrite Belt, located in the municipality of Aljustrel in the Alentejo district of Beja, Portugal. The site, which includes Poço Nº 2 and other shafts across the Algares, São João, Moinho, and Feitais deposits, has a documented history of metal extraction spanning more than five thousand years from the Chalcolithic period through Roman occupation and into the modern era. Modern systematic mining began in the mid-nineteenth century.
The concession was held from 1898 by the Société Anonyme Belge des Mines d'Aljustrel and its successors until nationalisation in 1975, when the operator became Pirites Alentejanas. The mine was classified as a monument in 1982. Large-scale extraction ceased in 1993 and resumed in 2008 under Almina – Minas do Alentejo, S.A., initially for copper then shifting to zinc-lead production.
The Parque Mineiro de Aljustrel now encompasses the abandoned portions of the complex, including surviving malacate headframe structures and the Central de Compressores de Algares, opened as a museum nucleus.
Metal exploitation at Aljustrel began at the end of the third millennium BC, during the Chalcolithic period, with evidence collected on the hill of Nossa Senhora do Castelo. This place is equidistant from the gossans at Algares and São João do Deserto, the two earliest exploited deposits. Bronze Age occupation was centred on the Cerro da Mangancha hill, closer to the São João veins. At the end of the first century BC Roman occupation commenced at Mangancha, with the establishment of a garrison and the foundation of the settlement of Vipasca, located near the Algares workings at the place now known as Valdoca or Vale da Oca. Roman mining extended into the fourth century, with production oscillating with the crises of the Empire, and slag deposits from the Roman period have been estimated at approximately 450,000 tonnes. After the Roman withdrawal, the deposits were largely abandoned, and near-surface outcrops were progressively exhausted in subsequent centuries.
The mine reappears in documentary record in the foral (charter) of 1252, where the Order of Santiago da Espada reserved rights to its profits. A sixteenth-century mining regulation, the Regulamento Mineiro de Ayres do Quintal, mentioned the mine at Aljustrel, and a document from King Dom João III referred to the existence of a pigment known as Azul de Aljustrel that was refined and sold by a royal functionary.
Modern systematic extraction began in 1845 when the first mining concession was attributed to the Spaniard Sebastião Gargamala, who opened the first extraction shaft and established the first mining settlement. The concession passed briefly to the Lusitanian Mining Company, and then to the Companhia de Mineração Transtagana, formed in 1867, which began large-scale extraction from the São João do Deserto deposit by opencast methods and from Algares underground, introducing rail transport and building the Pedras Brancas industrial complex. The first malacates (shaft headframe structures) at Aljustrel, initially of timber and driven by draught animals, were built in the mid-nineteenth century. Following the bankruptcy of the Transtagana company, the concession passed to the bank Fonseca, Santos e Viana, which became affiliated with Belgian interests to form the Société Anonyme Belge des Mines d'Aljustrel in 1898. This Belgian company held the concession until 1973, during which time the São João and Algares deposits were intensively worked and new veins — Moinho, Feitais, and Gavião — were discovered and developed. The complex reached depths of 425 metres by shaft and gallery methods. Compressed air tools were introduced in 1924, with the first compressor plant constructed at that time; the Central de Compressores de Algares, a larger facility, was constructed in 1952 with three compressor units, which remained in service until the early 1990s.
In June 1973 the concession transferred to Pirites Alentejanas, SARL, with the Portuguese state holding 50 percent, the conglomerate CUF holding 40 percent, and Mines d'Aljustrel retaining a fixed 10 percent. Following the nationalisation programme of 1975, the state took 90 percent of the capital, with the remaining 10 percent retained by Belgian interests. The mine was classified as a monument in 1982. In 1977 the discovery of the Neves-Corvo deposit prompted renewed exploration at Aljustrel for its economic potential. The deposit was extensively exploited from 1850 to 1993, when large-scale extraction ceased. In June 1973 the Poço Eyben at Algares had already been renamed Poço Vipasca as part of a remodelling of the Algares mine and its connection to the Moinho deposit; the iron malacate headframe of Poço Vipasca survives as a prominent landscape feature.
In 2001 the Aljustrel mining complex was acquired by the Canadian company EuroZinc Mining Corporation. In 2008 mining recommenced after a suspension caused by the fall in zinc and lead prices from October 2008. In 2009 Almina – Minas do Alentejo, S.A., a Portuguese group, purchased the mine from Lundin Mining Corporation (which had absorbed EuroZinc). Almina operated the mine for copper until April 2018, then converted the processing plant to zinc-lead-silver ore in March 2018. The Parque Mineiro de Aljustrel, an open-air heritage site managed by the Câmara Municipal de Aljustrel, encompasses the abandoned sections of the complex, with walking trails, the Chapéu de Ferro geological feature, the Galeria dos Algares accessible at 30 metres depth via the Poço Vipasca, and the Central de Compressores de Algares as a museum nucleus. The Museu Municipal de Arqueologia de Aljustrel holds collections covering five thousand years of mining history. Environmental remediation of the abandoned mining areas, including the Algares, São João, and Pedras Brancas areas, was carried out in four phases between approximately 2005 and 2015 by the Empresa de Desenvolvimento Mineiro, with a total investment of approximately 15 million euros from EU structural funds.