Restored pine-timber mine headframe from the Mina Marquesita, displayed in the Plaza del Liceo in La Unión, Murcia, as a heritage monument to the region's lead and silver mining past.
The Castillete Minero de La Unión is a wooden mine headframe originally from the Mina Marquesita at El Beal, in the Sierra Minera of La Unión, Murcia. La Unión's Sierra Minera has been exploited for lead, silver, iron, zinc, and other metals since prehistoric times, with Phoenician, Carthaginian, and Roman activity documented in the area. Industrial mining resumed in the mid-nineteenth century, and between 1860 and 1900 the Sierra Minera produced around twenty-four percent of Spain's lead output, making La Unión one of the foremost lead-producing centres in Europe.
The headframe — a four-legged pine-timber structure with two bracing tornapuntas, supporting the extraction pulleys — was used at the Mina Marquesita at the finca El Beal. In 1986 it was relocated from the mine to the urban plaza Asensio Sáez in La Unión town as a public heritage monument. It subsequently suffered serious deterioration from timber-boring insects and metal oxidation.
The Comunidad Autónoma of Murcia funded a restoration programme costing 44,000 euros, and in February 2025 the castillete was reinaugurated in a new location, the Plaza del Liceo of La Unión, as a symbol of the municipality's mining identity.
The Sierra Minera of La Unión and Cartagena has been continuously exploited for its mineral wealth since at least the prehistoric period, with evidence of lead and silver working at the Cabezo Agudo site within the municipal boundary. Iberian, Phoenician, Carthaginian, and Roman civilisations are all recorded in the area as mining operators. During the Roman period, the silver mines near Cartagena were among the most productive in the Iberian Peninsula.
During the mediaeval period exploitation fell to very low levels. Systematic industrial mining resumed in the mid-nineteenth century, driven by new industrial technology and rising global demand for lead and zinc. By the 1850s there were thirty-eight lead-smelting factories in the Cartagena region.
Between 1860 and 1900 the mines of La Unión and surroundings produced approximately twenty-four percent of Spain's lead, positioning the municipality among the principal lead producers in the world during that period. The municipality of La Unión was formally created in 1868, separating from Cartagena. Extraction was accompanied by significant social dislocation and labour exploitation: miners worked without safety guarantees, in dangerous conditions, exposed to occupational diseases.
A Hospital de Caridad at Portmán was established to treat the injured. Much of the wealth generated left the municipality; the silver and lead revenues funded modernist palaces in Cartagena. After a period of decline at the end of the nineteenth century, a second period of activity followed in the early twentieth century.
A further crisis developed from the 1920s. After the Spanish Civil War, new flotation technologies made low-grade polymetallic ores economically viable again. The multinational Peñarroya company dominated extraction between 1957 and 1988, introducing mechanised methods and achieving at its peak around forty percent of Spain's lead output.
Peñarroya also undertook submarine dumping of processed residues into the bay of Portmán between 1957 and 1990, depositing an estimated sixty million tonnes of contaminated material — one of the most serious industrial pollution events of the twentieth century in Spain. The Sierra Minera has been declared a Bien de Interés Cultural (Sitio Histórico). The last mines closed definitively in 1991.
The Mina Marquesita was located at the finca El Beal in the Sierra Minera. Its headframe — a four-legged pine-timber extraction tower with poleas at its apex and two diagonal tornapuntas bracing the structure — was detached from the mine and relocated to the plaza Asensio Sáez in La Unión town in 1986 as a public monument. It is an example of the simple timber headframe widely used in the nineteenth-century Murcian lead mining industry.
By 2024 the castillete had deteriorated severely, with xilófago insect damage to its timbers and metal oxidation throughout. The Consejería de Turismo, Cultura, Juventud y Deportes of the Comunidad Autónoma of Murcia funded a restoration programme of 44,000 euros. The work involved cleaning and void-filling treatment of insect-damaged timber sections, crack sealing, and protective wood treatment, as well as treatment of oxidised metal components.
The restored castillete was reinaugurated on 3 February 2025 in a new urban location, the Plaza del Liceo in La Unión, adjacent to the Museo Minero.