The Frongoch Lead & Zinc Mine is situated about 2 miles from Pontrhydygroes in mid Wales. The history and surface remains have been well documented in an excellent book by David Bick but I shall start by giving a brief description of the surface remains as they exist today.

Surface Features

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, enginehouses and other associated buildings. The lower workings to the West comprise the dressing floors and workings of the Wemyss Mine which once worked separately. Passing through the iron gate which leads into the upper workings, you pass a heap of spoil on the left and at the top is a rubbish filled depression which is Williams Shaft. Passing the ruins of the mine office, you next reach the ruined enginehouse associated with Engine Shaft. Climbing up to the shaft collar, it is possible to look down to where the shaft APPEARS to be filled with rubbish with the pump rod protruding through the fill.

Looking East, a huge opencast can be seen and, beyond that, an isolated shaft in the middle of a field marks the Eastern extremity of the workings. At one time it was possible to climb down into the open workings and reach a huge stope with a timber floor. A few years ago a fall of rock blocked this off. Above the enginehouse is a level, only a few metres long leading to a blockage, which may have been a manway down into the workings.

Back through the gate and down the road for a short distance, there is a panoramic view of the lower workings - dressing floors to the left, Wemyss Mine to the right and other workings on the same vein extending as far as Graiggoch Mine in the distance. Below and to the right of where you are now standing are the spoil heaps of Boundary Shaft. This shaft is oval and stone lined and again APPEARS to be filled with rubbish. Looking down at the Wemyss Mine, the square powder magazine stands out and, just above this, a depression and adjacent concrete engine bed mark the position of Balls Shaft. Below the magazine is an open incline shaft, connecting after a short distance with the top of a vertical shaft about 60ft deep. This is overhung with the actively collapsing false floor of an adit which has run in at the portal. I have not descended this shaft due to its condition and the lack of a suitable belay. Adjacent to the dressing floor is an open adit which leads to the blockage in Balls Shaft with some minor workings off.

Exploration of Deep Adit

To visit the Deep Adit, it is best to park your car just off the council road below the dressing floor and then enter the site via the gate. If you walk down hill parallel to the road, you will reach a cutting leading to the adit. This is a grotty looking hole with a large volume of water pouring out. It was not until the dry spell of 1995 that I felt like going in and even then in a full wet suit. My first visit was late April, at which time there was chest deep water at first followed by a series of three flat out crawls in fast running water. After this, normal progress is possible in waist deep water from a point where daylight enters from above. This is a narrow stope and, from below, looks about 10 metres. Standing by this "Adit Shaft" on the surface, however, and looking at the fall of ground down to the adit, it would probably be more than double this. There is no suitable belay point to use as a means of access to this shaft, you would have to drive a stake or something into the ground.

Proceeding inbye, you pass through an area where the roof has been stoped out to a height of up to 5 metres with much old timberwork. A "bait area" is also passed on the left. The adit trends E.N.E. with many twists and turns, passing the Wemyss workings altogether although two blocked passages on the right may have once connected. After about 400 metres, a 17 metre high chamber is reached. The adit then continues for another 60-70 metres to a forehead but, about 20 metres before this, there is a cross cut South to Boundary Shaft. The adit has a timber catwalk, a feature that was to prove useful later on.

In the vicinity of Boundary Shaft, there is an iron kibble and a long hooked bar used for pulling it in from the shaft. The shaft itself is blocked with rusting scrap metal just above roof height and also at floor level, but open to the height of the adit. The adit itself circumvents the shaft to the East and then cross cuts a major working. From here, going right (West) passes a blind heading on the left and reaches a flooded understope where water rises. This has a short length of ladder up to what was once a timber platform. Here there is a rise to higher workings. This place is the subject of one of the photographs in David Bick's book. Turning left (East) at the cross cut takes you about 30 metres under a stull to a forehead. A climb up a short length of ladder, however, takes you into a continuation of the adit, which again trends E.N.E. At one point the adit turns North and passes through an area which has been stoped in each direction, here the adit has been heavily timbered. This is the subject of the other photograph in David Bick's book.

After passing a flooded winze on the left, the adit reaches Williams Shaft which is solidly filled. As before, the adit circumvents the shaft to the left. About 20 metres further on, the adit was blocked by a solid collapse which had formed a cavity in the roof. There were signs that other explorers had attempted to dig through this without success (they were digging in the wrong place!). After this initial exploration, it became obvious that further exploration would be possible in two ways, ie by digging through the collapse or crossing the flooded understope. Regarding the latter, my instincts told me that there would be other flooded understopes and this was proved correct. Both "projects" were to prove successful and one at least was to lead me into workings where no modern explorer had been.

Exploration West (the flooded stopes)

The first was easily crossed using a 15" inner tube as a buoyancy aid. I also decided to fit traverse lines which were to prove invaluable later on. After the crossing, a climb over some rubble led me to an area where it was possible to look up into stope workings 70-80ft high. The next obstacle was a section of what appeared to be underwater false floor covered in rocks. I think now that it is more likely to be backfill that has settled over the years. It took my weight but I fitted a traverse line of sorts here. Next came another flooded understope, this time about 15 metres across, where another traverse line was fitted. It would have been very difficult to climb out of the water at the end but for a ledge on the left hand side. Here I found myself standing on a "bridge" of rock across the stope, a mere foot wide. The "hole" in front of me, although only a few metres across, had sheer sides rising several metres from the water. The opposite side also had a pile of loose rocks perched right on the edge. It was crossed by a rotten plank on two rotten stemples, clearly unsafe to cross.

My solution to this problem was to return to the adit and remove a section of the catwalk, however, being well sodden it wouldn't float! This was overcome by tying a tape sling round it and clipping it into the traverse lines. Once this was in position, the hole was safely crossed. A few metres further on, however, there was another flooded understope, this time with a timber catwalk in situ. The catwalk ended about 10 metres short. The stope was much narrower here so I was able to propel myself along using my hands, again with the inner tube as an aid. A bit of extra fun was three stemples a few inches above the water which had to be ducked. Out of the water and onward, the adit went for another 40-50 metres to a forehead, with blind headings to the left. At one point, I passed a laddered winze going down into blue water. There were clog prints everywhere and only one set that could have been modern wellies. However, I have to say that I had removed my heavy boots for the last "swim" as a safety precaution and it is possible that other explorers may have done likewise.

Exploration East (the dig)

I attempted this by digging in the same place as previously attempted by other explorers, without success. At one time I was absolutely exhausted, working in a confined space, in a wet suit, with poor ventilation. On 14/5/95 I returned with a long iron bar as well as my digging implement. This digging was being done by working inside the roof cavity formed by the collapse and all previous effort had been directed at the back, ie forward. Probing around with the iron bar, I was able to generate a draught by working on the left. Taking off my wetsuit top (what relief), I set to with a vengeance and was through in about two hours.

The passage beyond was in a few inches of water and after about 20 metres reached a Y junction. The right branch went into a large stope with a wooden launder in the floor. One section of mud was a mass of clog prints, some small enough to be those of children. The adit continued through the stope to a collapse. The left hand branch continued for another 80 metres to Engine Shaft, which is well and truly open underground. It is possible to look up to a height out of range of a caplamp. The pump rods, rising main and associated bits and pieces are all in situ. There are many other artefacts in this area, including a wooden wheelbarrow in an adjacent adit. Further digging past this point would be impossible, as the collapse is on the vein. I would like to end this article with a note of caution. It is only possible to enter these workings during a prolonged dry spell. Apart from the first section of the adit sumping out, there is every indication of the inner workings in the vicinity of Engine Shaft being under several feet of water at times.

extracted from "Frongoch Mine - an Underground Exploration", Roy Fellows, SCMC Journal No.3



Last revised: 21 April 1998