Dating from only 1835, Ty Gwyn (meaning ‘white house’ in Welsh) started much later than the other two mines on the Gt Orme peninsula (the ‘Old’ and ‘New’ Great Orme operations) and was geographically separate.
Great Orme (Norse for sea serpent) is a carboniferous limestone hill immediately to the west of the seaside town of Llandudno. Mining of Great Orme’s dolomite-hosted malachite was extensive 3,500 years ago (circa 1700-1400 BC) and the main site was worked again from 1690 to 1860. The original Bronze Age tunnels (over 8 km of them) were only discovered in 1987, and the prehistoric site was opened to the public in 1991.
The Great Orme mines were part of a group of operations in Caernarfonshire (the others being in Snowdonia) but the estimated total output of 3,000 tonnes of copper metal was dwarfed by production at Parys Mountain on the nearby Welsh island of Anglesey.
Evidence of copper mining on this hill (it has an elevation of only 150 metres) dates back nearly 4,000 years. Originally called Mynydd Trysglwyn (a tree-topped hill) the ‘mountain’ was renamed in 1406 after Robert Parys, who had received the land from Henry IV (1367-1413) as a reward for collecting taxes and fines from inhabitants who had supported the Welsh rebellion of Owain Glyndwr.
Evidence of the earlier Bronze Age workings was found in 1761, but the site didn’t become economic until a rich copper seam was discovered in 1768. At its peak, Parys Mountain employed 1,500 people and was the largest copper mine in the world. The operation slowly became uneconomic, however, and closed in 1904.
Parys Mountain was controlled in the 18th century by a local lawyer, Thomas Williams (1737-1802) of Llanidan, who also owned mines in Cornwall and operated copper smelters. Known as the Copper King, Williams was the richest man in Wales when he died, and at a Parliamentary monopoly investigation in 1800 admitted that half of the U.K.’s copper industry was in his hands.
Williams was instrumental in promoting the technique of covering ships hulls with copper sheets to protect them against molluscs and weeds. Williams sold to the navies of both England and her enemies, and the term ‘copper bottomed’ came to signify a sound investment.
The shareholders of Anglesey Mining Plc., which is the current owner of Parys Mountain, will be hoping the site is a copper-bottomed investment.
At the end of November, the company described Parys Mountain’s Northern Copper zone (NCZ) as “an exciting opportunity.”
This deposit was discovered in 1962, and an estimate in 2012 gave the zone an inferred resource of 9.4 million tonnes at 1.27% copper, 0.38% zinc, 0.24% lead, as well as 5 grams silver per tonne and 0.1gram gold (net smelter return cut-off of $48 per tonne). A preliminary economic assessment in January 2021 boosted 5.2 million tonnes of ore into the indicated category, with a further 11.7 inferred million tonnes at a grade of over 2% copper equivalent. Work in 2023 will include drilling into the NCZ to confirm historic grades and continuity and to seek further zones of high-grade mineralization.
In November 2022, Anglesey Mining’s CEO, Jo Battershill, spoke at the Mines and Money conference in London. He described Parys Mountain as having “world-class infrastructure, a supportive local community and, in terms of its geology, a lot of unfinished business.”
A geologist with over 25 years of experience in the industry, Battershill was appointed in August 2021 to lead Anglesey Mining’s investigation of the Parys Mountain deposit. There have been a number of failed attempts to restart the iconic mine over the past century; if Anglesey Mining succeeds, Battershill will join a long list of celebrated copper miners in North Wales.
— Dr. Chris Hinde is a mining engineer and the director of Pick and Pen Ltd., a U.K.-based consulting firm. He previously worked for S&P Global Market Intelligence’s Metals and Mining division.
