Parys Underground Group / Grwp Tanddaearol Parys

 

Bronze aged mining at Mynydd Parys

 

An understanding of the techniques used by Bronze age copper miners has been gained in the last few years following discoveries at various ancient copper mines.

It is known that bronze age man valued copper and bronze as both artistic and practical objects. The ore was gained by using only simple stone and bone tools.

It is thought that initially raw metallic copper found on the surface would have attracted the ancients to the uses of copper.  Before long they would have started to scratch away at the surface close to these raw metal findings with simple tools made of bone.  At the Great Orme mine in Llandudno a number of bone scraping tools have been found. These would have been used to scrape away loose rock and stones from the ore vein.

The bone tools would have been of use in soft rock.  The rock at Mynydd Parys however is very hard and would have soon destroyed bone tools.  In this area significant numbers of large beach pebbles have been found.  The geology of the stone is different from the natural rock and studies suggest they may have been brought in from Porth Wen beach.

These hammer stones or mauls would have been used to pound against the rock to break it into smaller pieces. Most of these hammers would be hand held , however a few show "rills" which indicate where they may have been tied into a cleft stick to be used as a hammer.

Where the rock was too hard to be broken up by the use of hammer stones the technique of fire setting would be used.
For this wood would be piled against a rock face.  A fire would be lit and the rock heated. Water would then be poured over the rock face causing it to crack and make the job of recovering the ore a lot easier.

Initially the ore would be recovered only from the surface. However later the ancients started to recover the ore from shallow open pits called bell pits.  At Mynydd Parys the base of some of these bell pits have been discovered up to 50 feet under ground

Entrance to possible Bronze aged surface workings near Amlwch

The type of copper ore recovered at Mynydd Parys contained the copper sulphur mineral called Chalcopyrite. Experiments have shown that if this is heated in an open fire some copper metal will be formed from the ore. However this is a poor and inefficient way of recovery the ore.

The ancients discovered that the ore was best processed by rough sorting and then crushing of the best ore with simple a stone pestle and mortar.  The crushed mixture would then be washed with water to recover the ore. A simple clay kiln would then be built in which the crushed ore was smelted to recover the copper. To obtain a high enough temperature in the kiln it is likely that charcoal and a bellows would have been required.  The molten copper would be recovered from the smelter and after mixing with tin and further smelting would be cast as bronze objects.

 

These ancient techniques worked well and the methods used out lasted the bronze age.  The Romans also used the same techniques at other copper mines and many European mines continued to use them through out the middle ages.  

========================================

Recent discoveries about bronze aged workings at Parys

Among the interesting features currently accessible in Parys Mine are the prehistoric sections.  Indeed, this was the justification presented to, and agreed by, the Marquess of Anglesey in 1995 in giving permission for underground access to be regained to a mine that had seen around 100 shafts and adits sealed in 1980 for insurance reasons. The 18th century miners had been aware of earlier activity and, for example,  “Roman workings” are indicated on John Reynolds’ map of 1764.   Oliver Davies excavated old spoil tips in the 1930s and recorded hammer stones and charcoal, ascribing them to the “Celtic/Roman period” though he did not then have the means to obtain a date from this evidence.  Positive proof for the prehistoric origins of the mine had only been obtained in 1988 by dating the charcoal in the rediscovered surface spoil from Davies’s dig.  This had indicated an age corresponding with the Early Bronze Age, making Mynydd Parys, comparable to other prehistoric mine sites in Wales, principally those of the Great Orme and Cwmystwyth.  However, whilst it seems likely that the Romans would have exploited known deposits of copper a thousand years later, only circumstantial evidence exists for any mining activity on the mountain, in the form of engraved copper ingots discovered there in the 19th century.  No direct evidence has yet been revealed, nor indeed at the other Bronze Age sites in Wales.

The logic for further research was that the possibility of finding more evidence on the surface of Mynydd Parys was unlikely, given the scale of disturbance in the 18th-19th centuries and the extent and depth of the resulting blanket of spoil.  What seemed more promising was to get into the underground workings and explore back up towards the surface.   This argument was spurred on by the embarrassing existence of an alien rounded stone, brought out of the underground mine in the innocent 1970s and used as a convenient doorstop for over a decade: in the 1990s this was recognised as a diagnostic stone hammer or maul.  All this led to the hire of Mostyn Rowlands and his JCB in 1995 and to a sunny day spent digging ever deeper on the site vaguely remembered from the 1970s as the entrance to Parys mine.   It was a relief when eventually a shuttered archway blocked by concrete appeared, and even more so when it proved possible to excavate a small body-tight opening above the concrete revealing space beyond.   We had thought that, maybe, after perhaps a year or so of careful exploration, evidence of prehistoric mining might be found.  In fact it took only about half an hour!    

The main site is at the NW end of the 16fm level.  Here a large work chamber had been driven upwards and had intersected the bottom of an earlier working, no doubt to the frustration of the 18th century miners.  The working was infilled with cemented spoil that now forms the excavated west wall and roof of the present chamber.   Of particular interest within the sloping bands of spoil is a roughly horizontal bed of banded clay some 30cm thick:  this was presumably formed by slow deposition in a temporary pond during a quiescent phase between two periods of active mining.  It is visibly rich in preserved organic debris including fragments of oak and birch wood, acorns, oak leaves, bracken fronds, spores and enigmatic fibrous material (hemp/nettles?).  The wood provided further material for 14C dating confirming an Early Bonze Age date (3540±40 yrs BP).  It is planned to date further samples from different beds to see if there is an age difference from bottom to top, an indication of how long the mining lasted.  The deposit also provides valuable information as to the surface environment at this time – obviously less acidic if dominated by oak and bracken in contrast to today’s bleaker landscape.  Successive sections have now been cut back in these deposits, cleaned, photographed and described, and a large amount of coarser organic debris recovered by washing that  will go for identification at Coventry University.  In addition, a vertical column has been excised from the clay ponding deposits for analysis of the pollen content to provide a more detailed reconstruction of the surface vegetation.  It may also be possible to match the results against a full dated pollen spectrum being produced for the nearby bog at Rhosybol that might further confirm the date of mining as well as revealing its impact on the local vegetation.

Other prehistoric deposits have been located nearby in the same work chamber including a small chamber with mauls and plant debris in the spoil, yet to be investigated in detail.   A small window in the roof of the passage also yielded wood fragments which gave a second similar date (3420±70 yrs BP) together with a small branch showing as yet unexplained, small (<1cm), ellipsoidal depressions.  These sites all cluster around what appears to be a large infilled shaft (Figure 1).   Another promising section has also been located at the top of the Grand Stope (20fm N) which is to be examined and sampled.   Hopefully it may be possible to gain access to open passages above these Bronze Age deposits that could yield much more information on Bronze Age mining.  One such site has already been located and dated to the West of Quarry Stope (16fm W) where 18th–19th Century workings similarly broke up into an earlier descending passage some 2m in diameter.   Ponded deposits had again formed at the bottom of this passage, and these contained wood which has been dated to 3600±70 yrs BP (Figure 2).  The passage leads up at a steep angle for some 10m before becoming blocked with spoil, and is perhaps similar in nature to those described by O’Brien from the Bronze Age mines (3400-3000yrs BP) at Mount Gabriel in southern Ireland.

There is much work to do in locating and investigating further sites and analysing samples to work out the methods and sequence of mining and reconstructing the Bronze Age environment.  Enticing, but currently inaccessible, openings exist above the Brown Pool, (16fm NW) and the upper levels of Mona mine have yet to be re-entered and their prehistoric potential explored.  With luck, artefacts that can survive the acidic environment may be found, such as pot fragments (although these are notably absent at other Bronze Age mines) and organic matter – the bones of a buried miner would be lost but his skin would survive!   But we are fortunate in that what has already been found has elevated the mines on Mynydd Parys to an international archaeological status enjoyed by only a handful of mines in the UK, and these mostly in Wales.   

From an article by Dr D A Jenkins ( University of Wales, Bangor)