Cycle “Dialogues with the classical world”, September 6 to December 20, 2017.

The Tresminas mining area is one of the most spectacular cultural landscapes in northwest Hispania. About 2000 years ago, a detachment of one of the powerful Roman legions settled in the Serra da Pradela to organise and control the large-scale gold mining of Tresminas and Jales (Vila Pouca de Aguiar, Vila Real, Portugal).
The spectacular traces of this exploitation can still be seen at Tresminas: two large mining cuttings (Covas and Ribeirinha) and a smaller one (Lagoinhos), as well as deep galleries dug mainly to allow the treatment and evacuation of all the extracted rock and an extensive network of water supply channels for the mines, which start in dams and end in storage reservoirs.

Galeria dos Alargamentos
There are also enormous dumps that fill the valleys and one of the most characteristic elements of this mining area: a large number of granite pestle and mortar mills used in the final grinding of the ore.
But there also remain important testimonies of the men and women who lived and worked in Tresminas, and who died there in the first two centuries of our Era. As a result of the activity carried out there for more than 200 years, these gold mines have become one of the most important in the entire Roman Empire. Today, the gold mining territory of Tresminas, being the most complex and best preserved and extending over several kilometres, is the most important in Roman Portugal.

The Roman mining of lapis specularis played an important role in the early Empire, during the 1st and early 2nd centuries AD, among the lapidary materials demanded and incorporated into the architectural programmes implemented, especially in the cities, due to the need for large windows that would allow light and sunlight to pass through, also allowing the exterior to be seen and ensuring climatic comfort. It was at this juncture that specular gypsum made its place as one of the best materials that met the required characteristics, and where the glass mines of Hispania, with greater production, and with a mineral of higher quality and transparency than those of other areas, would impose themselves on the markets, making this resource a versatile and essential product in many of its applications.

Francisco Javier Sánchez-Palencia (Institute of History, CCHS of the CSIC).

IX Lusitania International Round Table. Roman Lusitania: from past to present research.

The mining-metallurgical centre of Cerro de los Almadenes is located southwest of the village of Otero de Herreros and since 2009 several members of the Spanish Society for the History of Archaeology (SEHA) have been excavating at this site.
The archaeological work has located copper mines and a battery of ore reduction furnaces of a type hitherto unknown on the peninsula. The excavations have documented structures and materials dating mainly from the Late Republican, High-Imperial and Late Antique periods, although there are also remains from the 6th century BC. Monetary finds and the sculpture of a seated lady with her head removed also stand out.