Dolaucothi-Goldminen
The Dolaucothi Gold Mines (Vorlage:Gbmapping), also known as the Ogofau Gold Mine, are Roman surface and deep mines located in the valley of the River Cothi, near Pumsaint, Carmarthenshire, Wales.
They are the only mines for Welsh gold outside those of the Dolgellau gold-belt, and are a Scheduled Ancient Monument. They are also the only known Roman gold mines in Britain, although it does not exclude the likelihood that they exploited other known sources in Devon and Scotland for example. The site is important for showing advanced Roman technology.
Roman mining methods
Archaeology suggests that gold extraction on this site may have started sometime in the Bronze Age, probably by washing of the gold-bearing gravels of the river Cothi. Frontinus was sent into Roman Britain in 74 AD to succeed Quintus Petillius Cerialis as governor of that island. He subdued the Silures and other hostile tribes of Wales, establishing a new base at Caerleon for Legio II Augusta and a network of smaller forts fifteen to twenty kilometres apart for his auxiliary units. During his tenure, he probably established the fort at Pumsaint in west Wales, largely to exploit the gold deposits at Dolaucothi. Evidence from the fort (known as Luentinum from details given by Ptolemy) and settlement show that the Romans worked the mine during the first and second centuries AD (from circa AD 78 until around AD 140). They made extensive use of water carried by several aqueducts (the longest of which is about 7 miles from its source in a gorge of the river) to prospect for the gold veins hidden beneath the soil on the hillsides above the modern village of Pumsaint. A small stream high above the site, the Annell, was used initially to provide water for prospecting, and there are large tanks for holding the water still visible above an isolated opencast pit carved in the side of the hill. The larger aqueduct from the Cothi crosses this opencast, proving it to be later.
Hydraulic mining
The water was stored in the tanks and then released suddenly, the wave of water sweeping away the soil to reveal the bedrock and any gold-bearing veins beneath. Pliny the Elder gives a dramatic account in his Naturalis Historia of the method, possibly derived from his experiences in Spain. The method is known as "hushing" and survived in use until the seventeenth century in Britain. A not dissimilar method is used today in exploiting alluvial tin deposits, and is known as hydraulic mining. The same water supply was used for washing crushed gold ore, and also possibly driving stamping mills for comminution of the ore (Lewis and Jones, 1969). The first aqueduct was built at a high level on the east slope of Allt Cwmhenog and tapping a small stream about two miles away. There is a large tank at its end, where it sweeps aroung the brow of the hill onto the west side of the ridge. A gold vein must have been discovered here, because there is a large opencast below the tank. Yet the larger and longer aqueduct taps the river Cothi about 7 miles to the north-east and traverses the same opencast, so must be later in date.
Prospecting was successful and several opencasts are visible below the large tanks built along its length. The only exception is the final and very large tank, below which are two reservoirs. It is likely that this complex was used for washing powdered ore to collect the gold dust. More leats and tanks can be found below the line of the main aqueduct, some of which are shown on the map of the site. They surround the lip of the very large opencast at the base of the hill, and down to the road and the Carreg Pumsaint erected in the space beside a large mound, now thought to be a dump of waste material from crushing activities. The existing ponds above and below the minor road from Pumsaint to Caio, were possibly part of a cascade for washing ore, the upper tank having yielded large quantities of Roman pottery from ca 78 to 140 AD (Lewis, 1977). The upper pool is known as Melin-y-Milwyr, or the soldier's mill, an intriguing name that implies that watermills may have been used here during the Roman period. A large-scale mill complex is known from Barbegal in southern France, where no less than 16 mills (in two lines of 8 each) were built into the side of a hill and supplied with water from a single aqueduct, that same aqueduct which features in the famous Pont du Gard. There were two lines of parallel overshot mills, the outflow from one feeding the next below. The mill supplied flour to the region.
This site yields some of the earliest evidence anywhere for the Roman use of water-powered trip-hammers to crush ore (Burnham 1997).
Deep mining
They followed the veins with shafts and tunnels underground, some of which still exist on the site. The remains of Roman dewatering machines were found during the 1930's when the mines were re-opened briefly. The most interesting discovery included part of a reverse overshot water wheel which is now in the National Museum of Wales. A similar but larger example was rediscovered during mine operations at Rio Tinto in Spain, and is now in the British Museum, which also possesses most of the gold artefacts found in the last century at the site. Gold mining was sophisticated and technologically advanced, suggesting that the Roman army itself pioneered exploitation at the site.
Similar sites
These workings are comparable with those in the Carpathian mountains of Transylvania in modern Romania, at Rosia Montana, and with the Roman gold mines in north-west Spain, such as Las Medulas. The Romans may have used slave labour taken from the local area to work the mine, although the army itself was probably most directly involved, especially for their engineering skills in surveying and building aqueducts and water reservoirs. No evidence of the Roman minting process exists on or near the site, so the gold may then have been sent as far away as Rome to be minted. After the military occupation the mine may have been taken over by Romano-British civilian contractors.
Later history
Following the Roman departure from Britain in the 5th century, the mine lay abandoned for centuries. There was a short revival in Elizabethan times and in the 19th century; in the 1930s a shaft was sunk to 430 feet in an attempt to locate new seams. Falling into disrepair and unsafe due to flooding at its lower levels, the mine finally closed in 1938. It was during this period that ancient workings were found, and a dewatering mill discovered within. The remains are now in the British Museum.
The United Kingdom's National Trust has owned and run the site since 1941. Manchester and Cardiff Universities were active in exploring the extensive remains in the 1960s and 70s. The National Trust organises guided tours for visitors, showing them the mine and the Roman archaeology.
References
- Oliver Davies, "Roman Mines in Europe", Clarendon Press (Oxford), 1935.
- Jones G. D. B., I. J. Blakey, and E. C. F. MacPherson, "Dolaucothi: the Roman aqueduct," Bulletin of the Board of Celtic Studies 19 (1960): 71-84 and plates III-V.
- Lewis, P. R. and G. D. B. Jones, "The Dolaucothi gold mines, I: the surface evidence," The Antiquaries Journal, 49, no. 2 (1969): 244-72.
- Lewis, P. R. and G. D. B. Jones, "Roman gold-mining in north-west Spain," Journal of Roman Studies 60 (1970): 169-85.
- Lewis, P. R., "The Ogofau Roman gold mines at Dolaucothi," The National Trust Year Book 1976-77 (1977).
- Barry C. Burnham, "Roman Mining at Dolaucothi: the Implications of the 1991-3 Excavations near the Carreg Pumsaint", Britannia 28 (1997), 325-336
