Here we find an ancient scree-filled opencast working some 50 m long and of unknown
depth (but >15m deep) excavated at the top of the Comet Lode, on Copa Hill. The mineral
veins at this point carry galena (lead sulphide) and chalcopyrite (copper iron sulphide)
within an iron carbonate and quartz gangue.
The presence of “ancient workings” and stone mining hammers at this location was
first recorded in 1813, and in 1937 Oliver Davies re-examined this old site for the
evidence of early mining on behalf of the British Association for the Advancement
of Science. He concluded that the mine was Roman or “old Celtic” in origin.
Mining on Copa Hill circa. 2000 BC (Brenda Craddock)
The first modern excavation at this site were undertaken by Simon Timberlake in 1986.
A 12 m section was cut through the Central Tip exposing stone tools and buried charcoal
layers from which three Bronze Age radiocarbon dates were obtained (Timberlake &
The Early Mines Research Group carried out excavations within the opencast between
1989 and 1999, uncovering a landscape of rock-cut benches and pillars, a mine gallery
with the marks of stone tool use in its roof, emptied vein fissures as well as an
entrance or drainage cutting to the workings which lay buried beneath many metres
of weathered scree, peat and silt, plus slumped-in and backfilled mine waste.
The mine seems to have been suffering severe problems of flooding from at least 1850
BC, some 200 years after its discovery at the beginning of the Early Bronze Age
Excavations have uncovered a unique series of hollowed-out wooden logs of alder and
oak which were used as drainage launders (gutters) to tap the water issuing from
springs within the rock walls of the working, and then to guide this out of the mine.
One 5 metre section of 4000 year-old launder was found still in situ. within the
entrance cutting, here due to the waterlogged preserved conditions and the high level
of metal it contained.
Other organic artefacts such as red deer antler picks and hammers, fire-sticks, hazel
withy handles for the hammer stones, rope, basketry fragments etc. were also preserved.
Red deer antler pick/hammer
Hazel withy handles for the hammer stones
The miners had used simple stone cobble tools which they had brought with them from
the coast together with cut oak stemples for climbing down into the veins and oak
brushwood for fire-setting, a technique to soften and break-up the hard quartz-rich
In some places the lead ore had also been removed, but most of this was discarded
alongside the veins or in the waste heaps, either as lumps or else as crushed-up
Some of the galena may have been intentionally extracted as lead ore is easy to smelt
and work, even though there seems to have been little use made of it during the Early
Bronze Age in Britain.
This together with the evidence for the extraction and crushing of chlacopyrite,
plus the lack of evidence for its further processing, of any traces of smelting,
or of habitation, remains one of the many mysteries which surrounds this site (Timberlake
This website was made possible by a grant from the Cambrian Archaeology Association
It seems possible that the crushed copper-bearing vein material may have been washed
and just the oxidised copper minerals extracted from it. These then would have been
removed for smelting away from the mine.
The wooden log launders may also have been used for washing and separating the lead
from the copper, and the sulphide from the carbonate fraction of mineral.
A possible reconstruction of this process is shown below.
Withy rope or tie
Excavating within the entrance to the opencast in 1994 (Simon Timberlake)
Sectioned end of EBA alderwood launder in 1994. S. Timberlake)
(Photographs B. Craddock and S. Timberlake)
Stone chisel and lumps of galena within entrance cutting (S. Timberlake)
(Drawing by Brenda Craddock)
Malachite, cuprite and native copper within mineral specimen from Copa Hill opencast prehistoric mine spoil : microscope view under X-polars (Alan Williams)
Marks of stone tool use on roof of mine gallery. (B. Craddock and S. Timberlake)
Some 4-5 metres of this infill was sectioned; with radiocarbon dates and environmental
evidence revealing an abandonment history, spanning some 3500 years. (S. Timberlake
and B. Craddock.)
The gradual infill of this mine had been taking place since well before its abandonment
in about 1600 BC, after most of the copper mineral had already been removed.