Ogofau Mine (Roman Deep Mine; Dolaucothi Mine; Cothy Mine), Pumpsaint, Carmarthenshire (Dyfed), Wales, UK
UK Grid Reference: SN663402
Latitude: 52°2'37"N
Longitude: 3°56'58"W
The only Welsh goldmine outside of the mines of the Dolgellau gold-belt, the workings are of Roman or earlier origin and of considerable significance, their standing being comparable with those in Romania and the late Iron Age gold sites of Limousin in central France. It has been suggested (e.g. Hall, 1993) these very early workings exploited an oxidized zone, with the gold being removed from gossanous clays by washing and sluicing.
A series of pre-19th C pits and openworks, some with workings driven below them, run for over a km NE-SW along a mountain spur forming the SE side of the Cothi Valley. More modern workings have extended earlier workings; in the mid 1930s the sinking of New Shaft was resumed to a depth of 480 feet, with levels driven at 100, 160, 260, 360 and 460 feet to work the mineralisation under the Ogofau Pit. There is no dominant vein or lode, gold mineralisation occurring within a network of thin discontinuous veins with occasional lenses of gold bearing quartz.
Little is known about the pre 19th C working, with available literature prior to 1846 showing an unawareness of gold being mined here. Gold was rediscovered in 1848 by Sir Warington Smyth of the Geological Survey, and later by Sir Henry de la Beche, who made the first gold assay of quartz from the mine. Gold was worked in a short-lived operation in 1853, and small-scale mining resumed in 1871 until 1897.
Working resumed in 1905-06, with 381 tons of ore yielding 44 ounces of gold and 6.6 ounces of silver (for a profit of £172). Later in 1906 the Ogofau Mining Company processed 360 tons of ore yielding 28 ounces of gold and 5 ounces of silver (for a profit of £105). In 1908, 75 tons of ore yielded 11 ounces of gold, but development costs led to the lease passing to the Cothi Mines Ltd in 1909, who in that year recorded 23 ounces of gold from 96 tones of ore. Cothi Mines failed in 1912.
The main peiod of working began in 1933 with the formation of Roman Deep Ltd. At least some gold was produced about this time as gold from Roman Deep together with the Dolgellau mines, Prince Edward Mine and Marina Mine provided gold for Princess Marina's wedding ring in 1935 (gold from the bar produced was also used for other royal rings). By 1936, development was well advanced but the ore, auriferous sulphide concentrates, was difficult to treat and had to be sent abroad for smelting. Ore was initially sent to Hamburg, almost 300 tons of ore yielding 260 ounces of gold. Milling began in January 1938, with 16,862 tons of ore, mostly stockpiled, producing gold worth £11,106 (representing 1388 ounces at the then gold price of £8 per ounce). About this time the political situation in Europe made it impossible to continue to ship the ore to Germany and it was then sent to Seattle in America for treatment. By November 1938 funds were exhausted and milling ceased. Pumping was stopped the following year and the company was wound up in 1943.
The mine site is now a scheduled national monument run by the National Trust. It includes a visitors centre, a collection of 1930s mining machinery (from Olwyn Goch Mine near Halkyn in north Wales), and has guided tours of some of the Roman and the more recent underground workings.
Drilling undertaken by students at Cardiff University and alluvial gold occurrences in streams to the NE has shown that the mineralization continues beyond the immediate mine area Brown, 1993).
Visible gold is rare at Dolaucothi, although a few specimens are held in in the National Museum of Wales Collection in Cardiff. More typically, the gold occurs as minute inclusions in pyrite or arsenopyrite.
Mineral List
7 entries listed. 6 valid minerals.
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References
The Dolaucothy Gold Mines - Geology and Mining History, 2nd Edition, A.E. Annels & B.C.Burnham, Printed by University College Cardiff, 1986.
Hall, G.W., 1993. Metal Mines of Southern Wales. 2nd Edition. Griffin Publications, Herefordshire.
Brown, M.J., 1993. Exploration for gold in Central Wales. Mineral Reconnaisance Programme Open File Report 13, British Geological Survey.
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