Tours: The Laurion Silver Mines

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Opening RemarksLaurion Mines OverviewAn Antique MineExtracting the OreWasheriesSmelting and CupellationLaborClosing Remarks

• Aspasia: Welcome to the silver mines of Laurion.

("Who are you?")

("What do you think of this place?")

• Aspasia: The mines make me nervous. All those fumes can't be safe to inhale day in and day out.

("Let's begin the tour.")

• Aspasia: The Laurion silver mines were discovered between Thorikos and Cape Sounion near Athens. They were rich in mineral galena, and provided Athens with much of the silver necessary to mint its currency. Because of this, the mines were invaluable to the city, and the resources they provided helped turn Athens into one of the most powerful states in Greece. We will meet again after you've seen what the mines have to offer. Farewell for now, wandered.

Overvie of the Laurion site / 2010

Silver mines were extremely rare in Ancient Greece, which only increased their importance.

Athens started exploiting the Laurion silver mines at the end of the 6th century BCE, and used its metal to produce its currency.

Production at the mines exploded around 485 BCE, when an especially rich vein was discovered. The mines' abundant silver made Athens one of the weathliest cities in Greece.

They also provided the resources necessary to build a fleet large enough to defeat the Persians at the Battle of Salamis.

In short, the Laurion mines played an integral part in the emergence of Athens as a Greek superpower.

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Athens's coinage dates back to around 530 BCE. The abundant resources from the Laurion mines allowed the city to mint a prolific coinage renowned for the quality of its silver.

Like modern currency, Athens's coins had different values and weighs. The most-struck denomination was the tetradrachm, which weighed 17.20m grams. The coin, as its name implies, was worth four (tetras) drachmae.

The smallest coins - and the ones most commonly used in the agora - were the triobol (2.15g), the obol (0.72g), and hemiobol (0.369).

Silver galena from the Potosi mines / Contemporary

Exploiting the mines' resources required a lot of labor.

To meet this requirement and save on cost, Athens leased out mining concessions to its citizens, who had their slaves to do most of the work, alongside poor day-laborers.

In the 5th century BCE alone, there were anywhere from 10,000 to 30,000 people toiling in the mines of Laurion.

Together, the workers managed to produce an estimated twenty tons of silver per year.

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Ancient Greeks extracted a number of different metals like gold, silver, copper, tin, lead, iron, and mercury.

The most precious metals, silver and gold, were appreciated for their quality and rarity. They were used to produce coins, but also jewelry, other luxury objects, and even statues like the gold and ivory statue of Athena Parthenos.

Most metals were traded in the form of ingots.

Miners extracting clay, scene from a votive pinax / 570 BCE (Archaic Greece)

Mining in Laurion was a two-step process.

First, the ore was extracted, and then it was refined.

It took about sixteen kilograms of raw ore to produce a single pure silver drachma of about four grams.

Recovered artifacts from the mines provide some insight into the specifics of the mining process.

Galleries were dug to follow the veins of ore.

They were small, and did not offer much space for the workers.

They were also hand cut, it's believed that it ook whole days to dig only a few containers.

Once the galleries finally reached the veins, the ore was extracted and then crushed on mortar stone to prepare it for washing.

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During the Peloponnesian War, the Spartans occupied and fortified Dekelia, cutting Athens off from important roads. The slaves in Laurion took advantage of this opportunity, and 20,000 of them fled the mines. Because of this, silver extraction in Laurion ceased.

The closing of the Laurion mines had a significant impact on Athens's economy. Its treasury gradually emptied, and it was left with no funds to rebuild its fleet. Deprived of resources, Athens was forced to melt two gold statues of Athena Nike to strike gold coins. The city also produced bronze coins covered in a thin silver layer to imitate and replace its tetradrachms — a move that was criticized by the comic playwright Aristophanes.

In 404 BCE, when the Peloponnesian War was over, the mining of silver was virtually non-existent. it was only decades later, in 370 BCE, that entrepreneurs started leasing mines again. However, when Alexander the Great obtained a large amount of Persian silver in his conquests, the price of silver dropped so much that the yields from the mines were no longer enough to cover their running costs.

Washery of Thorikos / 2010

Mine workers used washeries to help clean rock from the ore.

The washing process required a large supply of warer, but Laurion was an infamously dry region.

To compensate, cisterns were built in the mining area to collect and conserve seasonal rainwater.

Once enough water had accumulated, workers poured it into wooden troughs containing rock and ore.

The water's flow separated the lighter grains of rock from the heavier ore, which was caught in depressions at the bottom of the trough.

The newly cleaned ore was collected for refinement, and the water was redirected back into a tank to be reused later.

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The concept of using water to separate ore from rock is still applied today by modern gold miners.

Pouring liquid silver into mold, from archaelogical experiment on Greek minting techniques / 2007

Once the ore was clean and dry, it was ready for smelting.

It's purpose was to isolate the silver in the ore.

To do this, the ore was placed in a conical furnance filled with combustible charcoal.

Bellows pumped air into the furnance to control the temperature.

Inside, the ore burned, emitting a toxic smoke that was evacuated through a chimney.

Eventually, the silver alloy was separated from the slag and collected for the last step in the refinement process: cupellation.

Cupellation removed any leftover lead from the silver.

The smelted alloy was placed in a cupel, an absorbent bowl made of bone ashes.

It was then put in a furnance, where it absorbed the lead and left only silver behind.

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The furnances used for smelting and cupellation required an enormous amount of fuel. Based on evidence from South American silver mines exploited under similar conditions, it's estimated that Ancient Greek mines required 10,000 tons of charcoal to produce one ton of silver.

Workers in a mine with inscription dedicated to Apollo / 3rd cent. BCE

While the mines of Laurion belonged to Athens, the city frequently leased them to private citizens who exploited the site from anywhere from three to ten years.

These citizens enlisted slaves and poor day-laborers to carry out most of the work.

The workers had a very low life expectancy — about three to five years — due to the hazardous working conditions.

The dangers they faced included toxic lead vapor in the air and lung-choking dust in the galleries.

However, they were fed well enough to keep up their work, and their combined labor managed to produce an estimated twenty tons of silver a year.

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The Athenian politician Nikias once bought a Thracian slave named Sosias for one talent — the equivalent of 6,000 drachmae, and 30-40 times more than the normal price of a slave.

The reason for Sosias' high price was that he was an expert in searching for and finding silver tunnels. Because of this, Nikias installed Sosias as the administrator of the 1,000 slaves he already had working at the Laurion silver mines.

Nikias' purchase paid off, and according to Lysias, the politician eventually accumulated a fortune of one hundred talents from his mining business.

• Aspasia: I hope you enjoy your trip through the mines. We talk so much of Athens' glory, but we often forget the city's power was due to tremendous amounts of work — work that often had a great human cost. What else would you like to do?

("I'm ready for the quiz.") ("Take on the next suggested tour.") ("Take me on a random tour.") ([LEAVE] "That's all for now.")

• Aspasia: Farewell, wanderer. Best of luck on your journeys.