Bronze age mining
Bronze aged workings at Mynydd parys
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.