What I can see

In Souriza is the archaeological site of the Lavrio Mines, where most of the workshops are concentrated. It is a “museum” of ancient mining and metallurgical technology. It is noteworthy how the miners managed to extract silver in very low content without using modern technology. There were three stages of work: enrichment, melting and cupping. In the enrichment stage, the pieces of stone came to the surface and if they had silver below 30%, they had to be enriched (cleaning, crushing and grinding), otherwise they went straight to the furnace for melting. Then, the material was washed in rainwater tanks (built on the rocks) and through the precipitation of silvery lead, the junk material was dumped (a more economical way than the use of charcoal). In the melting stage, the silvery lead flowed from the furnaces to a hole and at the same time was separated from junk materials. The furnaces required large quantities of wood, and gradually the forest was deforested, resulting in furnaces’ coastal transfer in the coming years. Finally, in the cupping stage, silver was separated from lead. The silvery lead was poured into cups, baked at 950 C, the lead was oxidized and flowed out of the furnace. This method of separation had been maintained till recent years.

What I can't see

The Lavrion Mines belonged to Athens and were crucial to its economy from the 6th to the 4th century BC. The monetary system was born here and the first coins, the “glafkes” (= owls- the athenian four drachmas), were the dominant currency in the Mediterranean until the Roman years. By the pre-Christian years, it is estimated that 3,500 tons of silver and 1,400,000 tons of lead were mined, 70% of which were mined in the years of Athenian democracy (5th-4th century BC). One ton of metal produced 40 grams of silver and 20 kg of lead. The water was scarce, so the laboratories envisioned a better economy and utilization. The wells for the deposit were vertical and reached up to 110m. The horizontal tunnels were up to 4km. (excavated 10m per month) and were 0.70-0.90m high, forcing slaves to bend or kneel, with little oxygen and bulbs for lighting. Athens leased the mines to businessmen every 3 or 10 years, on the condition that they pay a lump sum to the public treasury. They created huge fortunes and gained political power. Despite the miserable conditions (15,000-20,000 slaves), the businessman took care of the slaves’ longevity, because they were expensive and provided them with a healthy workforce, unlike in Egypt, where slaves were completely disposable. Conditions, however, were very bad and uprisings were often, as at the end of the Peloponnesian War, when slaves joined the Spartans’ side, mining works stopped and Athens’ economy collapsed. The latest information we have on silver mining is for the decoration of the Church of Hagia Sophia in Istanbul.

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