Although know for it's advanced Roman mining methods, this site, and it's surrounding water courses were almost certainly exploited during the Bronze Age. Any evidence for Bronze Age open cast mining or tunnelling would have been obliterated by the later Roman workings.
The Dolaucothi Gold Mines (grid reference SN662403), 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. The gold mines are located within the Dolaucothi Estate which is now owned by the National Trust.
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, North Wales 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, possibly by washing of the gold-bearing gravels of the river Cothi, the most elementary type of gold prospecting.
Sextus Julius Frontinus was sent into Roman Britain in 74 AD to succeed Quintus Petillius Cerialis as governor of that island. He subdued the Silures, Demetae and other hostile tribes of Roman Wales, establishing a new base at Caerleon for Legio II Augusta and a network of smaller Roman forts fifteen to twenty kilometres apart for his Roman auxiliary units. During his tenure, he probably established the fort at Pumsaint in west Wales, largely to exploit the gold deposits at Dolaucothi. Frontinus later restored the Aqueducts of Rome.
That gold occurred here is shown by the discovery of a hoard of gold ornaments in the 18th century. Objects found included a wheel brooch and snake bracelets, so named because they were soft enough to be coiled around the arm for display. All the objects are now held in the British Museum, and displayed in the Romano-British gallery. A sample of gold ore was found at the site by Henry de la Beche in 1844, confirming the presence of gold.
Evidence from the fortification (known as Luentinum from details given by Ptolemy) and its associated settlement show that the Roman army occupied the fort during the 1st and 2nd centuries AD (from circa AD 78 until around AD 125). However, coarse ware and Samian ware pottery recovered from a reservoir (Melin-y-Milwyr) within the mine complex show that activity at the mines continued until the late 3rd century at least. Since Ptolemy's map dates to about 150 AD, it is likely that it continued being worked until the end of the 3rd century if not beyond. The Romans made extensive use of water carried by several aqueducts and leats, 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. Small streams on Mynydd Mallaen, the Annell and Gwenlais, were used initially to provide water for prospecting, and there are several large tanks for holding the water still visible above an isolated opencast pit carved in the side of the hill north of the main site. The larger aqueduct from the Cothi crosses this opencast, proving the opencast to be earlier.
Following the Roman departure from Britain in the 5th century, the mine lay abandoned for centuries. There was a revival in the 19th century and attempts to make successful ventures at the site in the early 20th century, but they were abandoned before the First World War. 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 underground workings were found, and the fragment of the dewatering mill discovered within. The extensive surface remains, especially the traces of hydraulic mining, were to be discovered only in the 1970s by intensive fieldwork and surveying.
Between 1975 and 2000 the lease to the underground workings at Dolaucothi was held by Cardiff University. Students from the School of Engineering were largely responsible for the renovation of the underground workings that were made safe for tourists. The mine was extensively used as a training mine for Mining Engineering and Exploration Geology students under the supervision of Drs. Alun Issac, Alwyn Annels and Peter Brabham. Students from the School of Earth Sciences carried out an active gold exploration programme using surface and underground diamond drilling techniques, geochemical soil sampling and geophysics.Geological exploration was carried out by students using both surface and underground drilling methods. The ore processing waste tailings dam was also sampled, mapped geophysically and assessed for its Gold potential. The mine was extensively mapped and a library of Dolaucothi data is still held at the School of Earth & Ocean Sciences at Cardiff University. Cardiff University finally gave up the lease to the underground workings in 2000 due to the closure of its BSc Mining Engineering degree course. Photographs of surface and underground activities from the Cardiff University archives can be found from the links below.
Although there is yet no comparable site in Britain, it is likely that field work will locate other mines, simply by tracing the remains of aqueducts and reservoirs, and often, if not usually, aided by aerial photography. Physical remains like tanks and aqueducts are often recognised by the shadows cast by the structures in oblique lighting conditions. Thus Tank A was first seen in early morning light when the sun's rays cast an oblique light across the hill (Allt Cwmhenog) on which the structure is situated.
The United Kingdom's National Trust has owned and run the Dolaucothi gold mine and Dolaucothi Estate since 1941 when it was bequeathed by descendants of the Johnes family who had owned the mine and large surrounding estate since the late 16th century. Manchester and Cardiff Universities were active in exploring the extensive remains in the 1960s and 70s and Lampeter University is now closely involved with the archaeology of the site.
The National Trust organises guided tours for visitors, showing them the mine and the Roman archaeology.