Two miles east of Carmarthen, in the Hills south of the B4300 to Llandeilo lie the disused Llangunnor lead mines. The rich lodes of the hill were claimed to have been discovered in the 18th century, but there is evidence of earlier workings; including the discovery of boreholes filled with lime (that may predate the use of gunpowder in the district). In 1852 Thomas Field formed the Vale of Towy Silver-Lead Mining Company, which sank four shafts - Bonvilles', Clays', Fields', and Nant, of which Clays' was the deepest (124 fathoms) though all have been filled in by today. In 1853-4, old workings south of Nant farm were re-explored under the name South Towy. Little of value was discovered, but in 1861, due to failure of the main lode, the Vale of Towy took a lease on part of the property and dug an unsuccessful adit beneath 'an ancient mine' (pre-dating the 19th century workings) known as Pwll y Plwm ('the Pit of Lead').
Further east, the North Towy and Cystanog United Lead Mines Company began work on Allt Cystanog Hill. Two adits and two shafts were dug in 1853, in a line south from the road. The finding of good ore led the Company to sink a shaft on the north side of the road. By 1856 this shaft had reached a depth of 28 fathoms, with levels extending beneath the river, but disappointing results ended in the auction and eventual sale of the mine to Thomas Field. Field restarted the mine in 1859, but what little work was carried out ceased the following year.
A decade later, when the rich lode was discovered in old workings near the hilltop, the property was acquired by Matthew Smith of Hexham, who formed the Grand Duchess Silver-Lead & Barytes Mining Company. But for some unclear reason (possibly because the company did not have the funds to extract ore at a greater depth once the shallow ores were exhausted), the property was ordered by the High Court to be sold at auction.
In 1889 the discovery of good ore by local people, led to the formation of the Carmarthen Lead Mining Syndicate which held the mines until closure in 1902.
During this successful venture a deep shaft was sunk (52 fathoms) linking with a level and adit. At this time the company employed around 50 men, as opposed to 150 during the heyday of the Vale of Towy.
In order to work the lode below adit level in Clays' shaft, the Vale of Towy management erected a Cornish engine to pump water out of the mine. The engine had a steam cylinder of 50 inch diameter, which transmitted the slow power of the piston rod, to a pump rod in the shaft by means of a huge rocking beam (known in Cornwall as a Bob). By the action of the vast 'see-saw', water was drawn up the shaft through a series of hollow plunges to adit level.