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At Copa Hill (Cwmystwyth) studies have been carried out on the wood and charcoal recovered from the mine as well as on the pollen plant fossils and even beetle remains. These have been preserved within the peat and organic silt infill that accumulated both during and after mining had ceased. This can tell us much about the ancient environment thereabouts.
By coring those peat basins closest to these upland mines, and by dating the peat layers and counting representative samples for pollen, it has been
possible to construct some of the ancient vegetation histories. By this means we can detect any de-afforestation
which has taken place as a result of mining or smelting. In most cases, these Early Bronze Age mining events seem to have had little impact on the surrounding woodland.
It would appear that the mining campaigns were small-scale and probably only seasonal activities – sometimes carried out intermittently over several
hundred years.
The larger mines such as those on the Great Orme (Llandudno) may have been worked more continuously throughout the Bronze Age
Peat bogs can also provide us with a useful archive of past metal pollution.
Raised bogs that are rain-fed (ombrotrophic) collect atmospheric fall-out through time – for instance, the lead and copper present within wind-blown
dust emanating from nearby mines or else within smoke from smelting sites which collects and gradually accumulates in the surface vegetation of the bog. These variations in pollution then become fixed and immobile
within different levels of the peat. We can record these ‘peaks’ by digesting a succession of peat samples and then analysing these for the metals that they contain.
Early Bronze Age mining at Cwmystwyth is clearly revealed by the presence of elevated copper within the base of the blanket bog on Copa Hill.
Peat bog archives can also be used for detecting the presence of early mining or smelting where archaeological evidence is lacking.
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