Frongoch is not regarded as an ancient mine, first recorded mining being a lease of 1759 to a Philip Pugh. Later by John Probert of Shrewsbury in 1790, there is a shipping note of 1796 at National Library of Wales. Pugh or Probert very likely owned the neighbouring Wemyss Mine and shallow workings directly above the deep adit portal probably represent the earliest mining activity.

Intensive mining was started by the ubiquitous John Taylor who worked the mine from 1834 to 1878 and acquired the adjacent Wemyss Mine which was in separate ownership. This mine had a deep adit driven directly on the lode and this was extended and re-dialled to connect with the 24 fathom level. The re-dialling can be seen today in the deep adit with the earlier level high in the roof.

In 1878 the mine was acquired by John Kitto of Cornwall who worked the mine until 1898 when it passed into the hands of a Belgian company, Societe Anonyme Miniere, who instigated a process of modernisation through electrification. They acquired the neighbouring Graiggoch and built a generating station powered by water power at Pont Ceunant. They also built a new dressing mill at Wemyss. This company had spent a great deal of money that they were unable to recover and the mine was passed to another Belgian company formed for the purpose who managed to carry on until 1903. Main produce was zinc, the mine becoming one of the largest producers in the country.

In 1903 Crosswood Estate (Lisburne) commissioned an investigation by a mining engineer Thomas Garland, which we have.

Its likely that “unofficial” mining continued after, this had happened elsewhere in the area, but the mines were eventually acquired by the Lisburne Development Syndicate formed in 1907. The manager was Robert Nancarrow of Pontrhydygroes. He lived until 1964 and the late George Hall knew him. Nancarrow continued to be involved in a succession of new companies until it all came to an end in 1930. No underground mining has been done since the Belgians had pulled out, everything centred on the extraction of zinc from the dumps, the final phase being by electrolysis. The demand for zinc had been virtually non existent until the end of the 19th Century when the process of galvanising had been developed, as such, it provided the much needed boost to mining.

Nancarrow had been speculating on the feasibility of a small scale underground mining operation above adit and started work on his own account in 1929. About 1950 a Mr Dandrik did some exploratory underground work including driving an exploratory level, and much later a deep borehole was drilled in 1971.

Description written in 2026 by Roy Fellows being responsible for most of the underground works done in the last 30 years:

Geographically, the site may be divided into two areas bisected by a council road. The upper workings to the East comprise the main group of shafts, engine houses, and other associated buildings. There is also at the rear of the site a prominent opencast. It was possible at one time to descend to an area between two false floors with a possible route of further descent. This is now lost due to a collapse. The lower workings to the West, the dressing floors and workings of the Wemyss mine which once worked separately. The building are in a constant state of decay, the Engine shaft collar has gone and at the time of this writing, 2026, its a matter of speculation when the engine house bobwall falls down the shaft. There has been other surface subsidence with vehicles being lost into collapsing workings. There is no underground access in this area, the remains of a likely manway just below the road goes nowhere.

Below the road the Wemyss mine has the remains of the Belgian mill and a very large wheelpit filled in by a previous landowner. There is an open stone arched adit to Balls Shaft, but ends at a collapse near the filled in shaft. Further to the west is a short overgrown incline leading down to a likely manway shaft. The shaft down is overhung by massive boulders resting on broken and rotting timber. I attempted a descent some years ago but aborted the attempt. The ‘hanging death’ looks worse when you are underneath it and the bottom of the winze looked watered out, indeed it looks like it goes down to the 44 from the plans. What was interesting was that the winze was stempled all the way down as far as I can see. This is from memory.
The workings top of the winze are all collapsed and originally gained from a run in adit, the remains of which can be seen.

Lower down the ground levels out and workings extend towards Cwmnewydian Uchaf eventually ending near the road in the area of the deep adit. I am informed that originally there were mine buildings the other side of the road which were demolished when the land was converted to agricultural use. The deep adit was originally stone arched and cut and cover emerging near the road. All of this has collapsed and the entrance section partially filled by material falling from the previously mentioned early workings above. This originally meant a flat out crawl in running water for the explorer. In 2002 permission was granted by the landowner to muck out and cap with a manhole the small open stope at the head of the early workings. This was achieved and now gives reasonable access to the workings. Initial explorations ended at a collapse just short of Engine Shaft, however there were signs that someone had attempted digging it. Poking around with a steel I created a draught over to the left and started digging, I was through in about an hour.

Beyond, a stooping passage lead to a massive stope with small footprints, a continuation of the inward passage eventually lead to Engine Shaft with rising main (now lost) and pump rods still in situ. When discovered there was the remains of an timber balance box (now lost), a timber box of spares with iron shod corners, spanners, and the steel reinforcing and timbers of a balance bob, these still to be seen. Beyond the Engine shaft was a continuation of the adit, at a sort of “T” junction, an outbye passage leading towards the big stope but blocked, the inbye heading under timber to a fall. There is a small wheelbarrow in that vicinity.

The garland report indicates a massive zinc stope inbye, this and the plans have been the incentive for my efforts over years, all unsuccessful, to gain the workings past Engine Shaft. I attempted digging the passage at adit level behind Engine Shaft and was successful in gaining a short length of new passage. This was dangerous in that part of the side wall had fallen away leaving an overhang above. It had two rises, both blocked. Further progress inbye was halted by more collapse.

In 2005 I did some re-timbering of a stull near the boundary crosscut and improvements to the first dig.

In 2015 I laddered a rise up to the 14 fathom level. This was a heading west past a small stope to a forehead, nearby an alcove has a little seat. I think this was part of the later investigations.

East (Inbye) lead through decorated passage to a backfill area, I think material dumped from Mr Dandriks exploratory level. Past this Williams Shaft is reached, and further on ended in a collapse. It was possible to climb up on top of the collapse but no way on beyond. This was the site of my last digging attempt, an area forward was pushed being reinforced with steel and concrete in places. A final winze I sunk discovered that the level beyond is watered out. I could however on one occasion hear noises of a vehicle engine that must have been on the surface near Engine Shaft. I suspect a natural fissure allowing this. This area is best avoided as its very unstable, there has been two collapses, the later which caused me to give up completely due to safety concerns.

On access, Roy Fellows notes:

Lower site and deep adit is free access coutesy of landowner, Mr Arthur Edwards of Cwmnewidian Uchaf, a good friend to us. Park up by Wemyss and walk down to the bend in the road, there is a stile up the bank. Keep to higher ground and look for a small fenced area. There is a shaft with 2 manhole covers and fixed ladders, replace covers when you leave.

Wemyss is John Bray - generally allows access

Upper site is Mark of Frongoch Landrover Spares, best to look out for him and ask if leaving the public path. There has been a lot of Youtubers messing about up there.