Miniera di Abbadia San Salvatore — Pozzo Garibaldi Abbadia San Salvatore · Toscana · Italy

The Abbadia San Salvatore mercury mine occupied an area on the western flank of the Monte Amiata, a spent volcanic massif in the province of Siena. The presence of cinnabar — the red mercury sulphide from which metallic mercury is obtained by roasting — had been known in the Amiata area since antiquity, but systematic industrial exploitation was a product of the late nineteenth century.

The decisive step towards large-scale mining at Abbadia came in 1897, when the Società Anonima delle Miniere di Mercurio del Monte Amiata was founded at Livorno with a capital of five million lire, predominantly of German origin, under the technical direction of the engineer Friedrich Ammann. The company, known subsequently as Monte Amiata S.p.A., inaugurated industrial production on 31 January 1899 with the lighting of the first smelting furnace. Ammann had been preceded and aided in the identification of the deposit by Enrico Serdini, a local prospector who located a cinnabar outcrop at the Piano del Saragio from which open-cast extraction began. The metallurgical plant was designed around the Cermak-Spirek furnaces, introduced under the direction of the engineer Vincenzo Spirek, who served as director from 1897 until his death in 1907. These furnaces, capable of treating ten to twelve tonnes of ore per day, became the dominant smelting technology in the Amiatine field until 1956.

Between 1900 and 1920, the Monte Amiata mines contributed around 25 per cent of world mercury production, placing the Abbadia operation among the most significant mercury producers globally alongside the mines at Almadén in Spain and Idrija in Slovenia. In 1909, the company built the hospital at Abbadia San Salvatore in response to the high frequency of injuries among its workforce. In 1915, the German shareholders transferred their participation to a Swiss banking consortium, and during the First World War, production was placed under Italian military authority with financial management passing to the Banca Commerciale Italiana. In 1932, the effects of the global economic crisis of 1929–30 caused a first major contraction of the sector, with prices falling and employment reduced.

As a consequence of the 1930s crisis, the company was acquired by IRI and reconstituted as Monte Amiata S.p.A., remaining under that identity through the Second World War and into the postwar period.

The mine's surface layout underwent its principal expansion from 1938, when Pozzo Garibaldi — at the time called Pozzo Impero — was begun. This was the last of the external shafts to be constructed at the site, complementing the existing external shafts Pozzo Italia and Pozzo Mafalda, and the internal shafts Mili, San Callisto, Pozzo Nuovo, and Pozzo Ausiliario. The underground workings were organised on gallery levels at 25-metre vertical intervals, with cages descending from the shaft to circulate mineral wagons and personnel. Around Pozzo Garibaldi a cluster of surface buildings was progressively assembled: a carpentry workshop; a mechanical repair shop for underground machinery; a compressor room supplying compressed air through metal pipes to underground equipment; the technical and planning offices; and in 1949, the miners' bathhouse and changing rooms, designed by the architect Eugenio Montuori and engineer Leo Carlini. The complex also included electrical substations, an explosives store, storehouses, material silos, a gatehouse, and a small infirmary. The mine at this stage was extracting cinnabar which was conveyed from underground via rotating screens (vagli rotanti) to essiccatoi where moisture was removed before the ore reached the roasting furnaces. In the furnaces, mercury vapour was driven off from the cinnabar by heating and subsequently condensed and collected as liquid metal. The work was divided across three shifts daily, with a siren indicating the start of each shift at 06:00, 14:00, and 22:00.

By around 1969–70, a worldwide crisis in mercury demand developed, driven largely by environmental concerns and by competition from low-cost producers in developing countries. In 1972, the entire Amiata mercury basin, including the Abbadia San Salvatore mine, ceased production definitively. The mine by this point had 35 kilometres of galleries extending to depths of up to 400 metres. In 1974, the concession passed first to Solmine of the EGAM group by ministerial decree of 14 January, and subsequently on 21 November to the Società Mercurifera Monte Amiata (SMMA). The concession subsequently passed through SAMIM S.p.A. of the ENI group following the dissolution of EGAM in 1980, and eventually to ENI directly, before the current concession was passed to the Comune di Abbadia San Salvatore by Regione Toscana decree in 2008.

With the dissolution of the industrial operation, the mine buildings deteriorated. The transition to heritage and museum use was formalised by Law 388 of 23 December 2000, which established the Parco Museo delle Miniere del Monte Amiata. The museum at Abbadia, known as the Parco Museo Minerario di Abbadia San Salvatore, opened and expanded progressively. It is structured around three main visitor circuits: the Torre dell'Orologio documentary museum (occupying the former factory entrance building that originally housed the Cermak-Spirek furnaces of 1898); the multimedia installation in the former Officina Meccanica, opened in 2016 and created by Studio Azzurro; and the didactic gallery on Level VII, where visitors travel by original miners' locomotive through 250 metres of restored underground workings. The exterior of Pozzo Garibaldi with its associated surface buildings became accessible to visitors in the summer season as part of the expanded park circuit.