Bronze age mining
Copper has been used by human beings for at least 7000 years. The island of Cyprus was a major source of copper for the ancient world. Our word copper came from cuprum the Roman's name for Cyprian Metal.
Other areas of the Mediterranean also had important prehistoric copper deposits. In many areas it was found as nuggets and masses or raw or native copper on the surface of the earth , adjacent to streams and in the walls of canyons.
These initial sources were copper metal which was a distinctive reddish brown colour. The ancients soon found that the malleable metal could be beaten into the shape of crude weapons, ornaments and domestic utensils. This was the first transition from the stone age. Beaten copper objects from 4500 BC have been found in the middle east. There is also evidence of it's use by Native Americans from the same period.
It is possible that people making pots on open fires first found that if the copper metal ore is first heated it became less brittle and easier to work. This process is known as tempering. The edge on a tool or weapon made after tempering was harder and more durable. It is thought that abrasive stones were also used to cut and grind copper.
Most copper is found combined with other elements to make minerals. The copper in these minerals had to be removed by smelting processes before the copper metal could be worked into tools.
The minerals of the ancient world included purple cuprite which was a combination of copper and oxygen , the green malachite which is a copper carbonate and another copper carbonate blue azurite. These are all fairly low melting ores. However they all required the use of a fire which was considerably hotter than that used for normal cooking. Copper metal melts at 1084 degrees C.
Some of these ores were found in association with another copper minerals the blue green turquoise which was recovered for it's decorative effect.
In the Middle East the remains of open hearths have been found. These were holes in the ground about two feet in diameter. They were lined with fire resistant clay bricks .Charcoal was placed in a layer on top of the clay bricks. The charcoal was then covered by the copper ore. Charcoal burns with a very hot temperature which was sufficient to melt the copper ores. It also releases gasses which reduce the copper in the ore back to the metallic state. A heavy molten mass of copper formed and the charcoal reacted with the gangue in the ore to form lighter molten slag. The hearth was allowed to cool and the metal and slag separated.
From modern experiments it has been shown that 300 kg of charcoal in required to smelt 1 kg of copper metal from cupriferous sulphide ore. Approximately 5 cubic meters of wood would be needed to produce the charcoal.
A later , more complex method was developed which used the crucible. This was a ceramic pot into which charcoal and the copper ore were placed. The crucible was placed in a furnace , bellows made from skins directed air to raise the temperature in the furnace. The charcoal and copper ore in the furnace reacted in much the same way as in the open hearth to produce copper metal and slag.
It is likely that smelting to recover the copper also lead to the discover of casting when liquid metal was poured into moulds. Copper ingots were cast into shape of bars and rings for transport to the centre of commercial activity. It also allowed the mixing of metal to form alloys. It was discovered that mixing copper with tin made a harder material called bronze.
It was to be another 4000 years in around 600 BC before it was discovered that mixing copper and zinc in an alloy gave brass.
The discover of bronze and it's usefulness in making tools and weapons, increased the demand for copper. It was no longer possible to supply the demand from just surface won copper metal and ore. Other methods of finding copper were required. This lead to the development of primitive mining techniques.
It is likely that the first mines were simply people digging down into surface deposits of known copper yielding ores. At Parys mountain and other sites the remains of evidence of "Bell pits" have been found. These are shallow surface pits that were dug using stone , copper or later bronze implements. Crude picks, hammers, chisels and shovels would have been used.
During later centuries when under ground mining commenced some of these " ancient Druidical workings" collapsed. A number of these have been found under ground at Parys mine. The collapses contain of a mixture of hammer stones and oak charcoal. Three samples of charcoal have been radio carbon dated by the British Museum and have returned dates of 3500 to 3600 BC.
Some of the bases of the bell pits found at Parys mine are up to 20 meters under ground.
There are two other sites in Wales at the Great Orme in Llandudno and Cwmystwyth which have had radio carbon evidence of copper winning of a similar age. This shows that copper was being recovered in Wales at around the same time as in the Middle East. It is likely that similar methods were being used.
Article on Bronze age tools from British Archaeology.
It is thought that many of the techniques from the middle east were brought to the British isles by the wandering Bell Beaker Folk. They also introduced bronze to Britain and Ireland. There distinctive bronze knives and axes have been found in County Wicklow in Ireland.
The charcoal in the collapsed bell-pits is accompanied by hammer stones. These are quartzite pebble stone which are foreign to Parys mountain but can be found on the local sea shore. Some of them have evidence of being used to chip away the surrounding rock and some have flat ground surfaces where then were used to beat or grind the ore.
In 1936 a Mr Davies from Queens university in Belfast reported on a dig he supervised on an ancient dump found near to the surface windmill on Parys mountain. The dump yielded 24 hammer stones and large quantities of oak charcoal. The charcoal was not associated with slag and had been used for fire setting rather than smelting.
Fire setting was a method developed by the ancients to recover copper ore from rock which was too hard for the primitive tools of the day. Logs were piled against the rock face and a fire set. The rock face was heated to high temperatures and then water was poured onto it. The sudden change in temperature caused the rock to shatter making recovery easier. In the Great Orme mine at Llandudno the remains of under ground fire setting can still be seen.
These underground fire setting sites in Wales are in small seams close to the surface. There is no evidence for extensive under ground galleries or stoops.
However in Egypt at around the same time the excavation of large under ground galleries by slaves was common. Pillars of un-mined rock were left to support the roof. The large quantities of copper bearing ore mined in these area lead to the development of a wide spread commercial trade in the region. Guilds of metal smiths were formed and there knowledge closely guarded.
The primitive Stone Age had given way to the developing Bronze Age which lasted from around 2500 to 1000 BC
In around the 5th century BC the state of Lydia in Western Turkey invented the idea of coins as a medium of exchange. Coins were small and portable, had a set value and were more convenient for trade than the bulky system of barter which had been used before. gold ,silver copper and bronze were used for coins. Greek coins with the head of an owl on the back " Owl coins" were the most important medium of exchange and the idea of money had been born.