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Tres Minas Gold Mines
About
The largest open pit at this Portuguese gold complex runs 500 meters long and drops 100 meters deep, cut entirely by Roman hand tools and hydraulic sluicing. A full settlement grew up around the workings, complete with baths and an amphitheater for the miners. Gold, silver, and other ores came out of the Tres Minas, Gralheira, and Jales deposits together through the 1st and 2nd centuries CE, squarely spanning the year 117.
What happened here
Work goes on underground by lamplight in shifts, and the lamp is also the clock. Galleries follow the ore, propped with timber, drained by wooden screws and bucket wheels worked by hand in stages up the shaft. Ventilation is a second shaft and a fire to draw the air. The labour is convicts, slaves and paid men working side by side on different terms, and the paid men do the skilled cutting. Above ground the ore is crushed, washed in long channels, and smelted, and the smoke kills the vegetation for miles. Mines of any size are imperial property, leased to contractors under written regulations covering shifts, drainage, bath-house charges and who may open a new gallery. Settlements grow around them fast and empty just as fast.
In ancient writing
- Pliny the Elder, Natural History 33.70-72
Describes the hydraulic gold-mining galleries dug into mountains in Asturia and Gallaecia, the region where this mine operated.
Sources
Nearby
Roman Maps shows the empire frozen at 11 August 117 CE, the day Trajan died — its moment of greatest territorial extent. Explore the full map →