The 1509 discovery of alum in Rodalquilar

Rodalquilar is a small village located in the municipality of Níjar, in the province of Almería. The discovery of gold in Rodalquilar occurred by chance in 1864. The mining history of the area includes the extraction of alum, a dye fixative that was of great importance. Alum mines, known as "tollos," were open-air trenches, many of which are still identifiable today. The search for alum began around 1445, and the mineral was discovered in Rodalquilar in 1509. Production of alum stopped in 1520.

Pirate attacks were common, and in one instance, the entire old village of Los Alumbres was raptado. To protect the area, the castle of Torre de los Alumbres was built. The Torre de los Alumbres appears in the spaghetti-western La muerte tenía un precio by Sergio Leone. In Rodalquilar, a gold fever began in the 1880s, involving various companies and individuals from around the world. In 1933, Rodalquilar had about 1000 inhabitants, and by 1960, it had become the second most populous settlement in the municipality of Níjar with 1345 inhabitants. However, by 1986, the population had dropped to 79 inhabitants following the closure of the mines.

Two main mining phases can be distinguished. The first is associated with alum, while the second is associated with gold starting in 1931. In 1915, gold was discovered in the "María Josefa" mine. Two private companies owned by local miners first attempted gold beneficiation in 1925 and 1929-1930. A company called "Minas de Rodalquilar S.A." was created in Madrid in 1928, headed by Fernando María de Ybarra, the Marquis of Arriluce de Ybarra. In 1931, this company achieved outcropping extraction of gold through cyanuration, building the Planta Dorr complex. The operation continued successfully until 1936, when the mines were seized by syndicalists who attempted to operate them during the war.

The gold of Rodalquilar was a personal project of general Franco, but it resulted in a significant waste of public resources. The mines passed to the Instituto Nacional de Industria (INI), which created the company Adaro for their exploration and bought the Minas de Rodalquilar company. The mines were expanded in 1956, during which approximately 600 tons of mineral were processed daily from the Cerro del Cinto quarries. However, because costs were higher than the value of production, the mines closed in 1966.

Geologists maintain that, historically, alum mining was much more important in this location than gold mining. The gold found in Rodalquilar is of volcanic origin, and was formed around 11 million years ago. While some prospecting methods provided quantitative data, there were instances where miners took samples they estimated were the best for laboratory analysis, which could distort the results.

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons