The Gold That Moved Mountains

By Awake! writer in Spain

“A cathedral of clay with multiple pinnacles has been sculptured out of the mountain. Gold and Rome were to blame. Time and beauty have forgiven them.”—Pedro García Trapiello.

IN THE northwest of Spain lies a strange rock formation gouged out of golden sandstone. A carpet of verdant chestnut trees creates the illusion that the rugged cliffs and soaring towers have been carved by the forces of nature. Only the occasional opening to a tunnel hints at an ancient secret. Here, in a place now called Las Médulas, once stood the greatest gold mine of the Roman Empire.

Gold has always had a fascination, which has compelled men to go to great lengths to get their hands on it. The Bible book of Job describes how millenniums ago ‘men dug the shafts of mines, dug mountains away at their base, and tunneled through the rocks’ in search of gold, silver, and precious stones.—Job 28:1-10, Today’s English Version.

Centuries later when Rome ruled the world, gold was still at a premium. Emperor Augustus wanted a stable economy, and the silver denarius and the gold aureus were the trustworthy coins that he needed to oil the wheels of Roman commerce. To mint sufficient coins, of course, he required gold and silver. Thus, hard on the heels of the conquering Roman legions came the gold prospectors.

When the legions finally subdued northwest Spain, not long before the start of the Common Era, they discovered new reserves of gold. Unfortunately, the precious metal lay buried in mountainous alluvial deposits that did not give up their gold easily. It would take two and a half centuries of toil and sweat to unearth the hidden treasure.

The Romans, however, were undaunted. Labor was cheap, and mining techniques of the time—though laborious—made the project feasible. Their plan was to extract the gold by gradually washing away the mountain. To achieve their aim, they constructed over 50 canals, built several large reservoirs high in the mountains, and dug hundreds of miles of tunnels.

Once a network of tunnels had been built inside a portion of the mountain, the engineers flooded them with water under pressure. The surging waters broke away tons of earth. The gold-bearing sand and rock was washed down the mountain, where the gold could be separated from the gravel by panning and sifting. Then the whole process would be repeated with the construction of another set of tunnels.

Was the effort worth it? The Romans patiently  extracted some 800 tons of gold from Las Médulas. To obtain all that gold, thousands of workers literally moved mountains—more than eight billion cubic feet [240,000,000 m3] of earth. And for every ten tons of earth that they excavated, they obtained one troy ounce [30 grams] of gold.

Nowadays, little remains but the tunnels and the jagged scars of the ruptured mountain, which have been polished by erosion and clothed by forests of chestnut trees. Ironically, these sweet chestnuts that the Romans introduced into Spain have proved much more durable than the gold.

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Gold coin (aureus) bearing the head of Emperor Augustus

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Las Médulas, the location of the greatest gold mine of the Roman Empire

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Part of the ancient tunnel system

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All coins: Musée de Normandie, Caen, France