A truly real place

Modern Underground Exploring Attire

Within seconds of parking up Scott was donning his flowery pink all-in-one thermal caving suit. Dean and Ian seemed obliviously to the fact but I couldn’t help raise an eyebrow. Here was an underground explorer on the cutting edge of his game, a very dangerous game at that, and it didn’t seem to cross his mind that he might one day and have to face the gates of heaven in a pink one-piece! Embracing the mood and as I slipped into my all-in-one, I joking asked, “is it alright to wet yourself in these things?”. “Absolutely”, as if proposing a toast, Scott exclaimed. Clearly my joke hadn’t been viewed as such and I suddenly felt a little indecent.

We began the long walk up from the small village of Croesor in North Wales towards the long disused Croesor and Rhosydd Slate Mines. They ceased slate production in the 1930s, after around 100 years of effort and employed around 500 men at their peak, producing in excess of 11,000 tons of finished slate annually.

Rhosydd is the larger of the two mines and originally operated by a completely different mining company although occupying the same mountain as Croesor. At some point during their heyday the two accidentally overlapped and formed a physical connection through which it is still possible to pass today. In 1900 a large section of Rhosydd caved in burying many miners and since, both mines have suffered other large collapses destroying the main underground passages. The whole mine is now largely shattered.

Both mines are also deeply flooded. More than a third of Rhosydd is below the water level, and more than half of Croesor has been lost in the same way. Miraculously, despite the numerous collapses, flooding and rock falls in both mines, it is still just about possible to enter one, go right to the other end, pass through into the other and exit. The journey remains one of the classic and most dangerous adventures for the underground explorer.

Due to its inaccessibility and technical nature it is reserved for the few that dare make the trip and have the necessary experience. The apathy of the whole situation was made a little worst by the fact non of my guides, regardless of previous experience, had ever completed the full trip.

Whilst walking Ian shows me a chart that looks vaguely similar to a child’s spirograph and I begin to worry. Firstly, Scott’s choice of underwear is a little odd and now Ian decides it is good time to show me his sketch collection. My face said it all and Ian explained that several maps are all layered on top of one another in different colours. Each colour represents a different floor level in the mine and if you think 3-dimensionally you can determine your lateral and vertical position within the mine.

Croesor Mine Entrance

Mine entrance

The entrance to the mine is through a small metal grill, sealed in the 1930’s but since crudely reopened. With shadows deepening around us, we say goodbye to daylight for the next 24 hours. The initial passageway follows rail lines used to the slate along in large carts. Water pours from the walls and we are soon walking through 4-5 inches over submerged sleepers. The passageway clears and opens out into a large room, off which several other passages escape into darkness. Ian determines that we are on level A, roughly the middle level. Since we’d exit Rhosydd at approximately the same altitude you would have once been able to walk the whole way through without having to change level. However, with the extensive flooding and collapses the route through would take us on a very non-direct line, rising and falling several levels and twisting between passageways.

Immediately on our right was the first sign of flooding. A chamber filled with water that conveniently rose to just a couple of inches of the ground we stood on. The huge underground lake looked haunting and darkness enveloped her in a shroud of unease. A quick look at the spirograph confirmed it extended down another 5-6 levels making it at least 300ft deep.

Dean begins climbing up a steep wide passage of about 45 degree which Ian explains is the main incline used to winch and lower slate to the level we were on and then taken out via cart. Machinery and artefacts from a lost way of life were strewn everywhere.

We followed making use of old cables to aid our way. Ascending 3 – 4 levels we were able to look down 100ft over the lake to where passages could be seen on the other side, once accessible by wood bridges now a long time collapsed.


Preparing to descend into Chamber 1 East

Nearing the top a side passage entered Chamber 1 East. A near unimaginable space with darkness you can feel and silence you can hear. A veil of black through which our most powerful torch could not penetrate was hiding the unknown and the point of no return. Chamber 1E was huge void left by a massive collapse in 1936 segmenting several levels.  Our decent would take us about 150ft down into the heart of the mine. The entire volume is unknown but it would not be unreasonable to compare it to the dome of St Pauls Cathedral.

Scott setup the rope for our abseil and after ensuring it was safe to proceed, descended first in complete silence. Ian explained it was apparently the excessive noise of previous explorers that brought a portion of the roof down in the 1990’s resulting in a long and difficult rescue.

I was the third to go. I’d had plenty of abseil and caving experience but silence had never previously been on the menu. Suspended in the darkness like a bead on a thread, I tried not to displace loose slate. I could see Scott as a tiny flicker of light in the distance below moving across the chamber floor in search of the way through. I reached the bottom without incident and awaited Dean.

Leaving a good distance between each person we cross the chamber to reach an opening a wall linking the next chamber. An equally large void fell beneath us and another equally long and trick abseil ensued taking us further into the belly of the mountain. We all tried to put thought to the back of minds that, should we need to retreat, the ascent up the ropes we had left in place would be extremely difficult.


Zip-wire across the first lake

This chamber was narrow enough to see to the other side.  We made our way along the wall towards a 2nd underground lake. As our lights penetrated the immaculately clear water it was not only apparent how incredibly clear it was, but also how unnerving deep.

Bolted to one wall was a thick steel cable. It quickly dawned on me that we were to use this as a zip wire and we each agreed that a swim in these waters would likely be our last.  Drowning; the invisible work shattered in my mind as Dean was  off into the darkness without hesitation. I quickly focused and flashes from my camera gave us a glimpse of the small landing strip.


The SS Explorer

The zip wire did led directly to a small passage on the opposite side of the lake and through to another chamber. Without issue we all safely arrived in the small passageway between two bodies of water. “Behold the SS explorer” exclaims Scott, pulling a deflated rubber dingy from his rucksack! We all took turns inflating it by mouth and as Scott took the maiden voyage he trailed a thin line of accessory cord so that we could pull it back.

Were we now well into the mine, exploring parts rarely visited since the 1930’s. Rail tracks ran off in most directions down smaller passages and cart wheels were irregularly strewn about. Some very rudimentary ladders hung at the end of the chamber up a steep bank of slate onto the level above.


Old cart wheels lay strewn about

We began following the tracks as this would take us along clearly marked routes on the map. This section of the mine was mostly in tact. Each small passageway ran for approximately 50 yards before opening out into another large chamber extending back and upwards. These chambers had been carved out by hand and the slate produces hauled along the tracks we followed, eventually reaching the main incline and entrance to the mine.

We continued on until the route ahead gave way to thin air. The continuation of our passageway could be seen across a dark expanse which fell 20ft to the water level. This would have been completely impassable we’re it not for the remnants of a bridge. Being one of the original wooden bridges adjoining the passageways, the previous century had not treated it especially well.

Two huge beams ran across to the far side support in mid-air by two more large horizontal joists that we’re, in turn, supported by highly rusted iron bars fixed into the roof. The whole contraption was in serious disrepair and was due a murky demise at the bottom of the mine in the not so distant future. I sure that when it does, it will surely be triggered by explorers, like us, walking over it. One by one we all reach the far side unscathed.


Camp for the night

It was now 8pm and we decided to make camp for the night in chamber with numerous interesting artefacts including a newspaper article dated 1929. After a warm supper I lay there appreciating the rare darkness. I flicked my torch on for a minute to admire again the collection of pots, newspaper cuttings and other items I can collected before dinner. I peered at them from my air mattress as they gloated in their knowledge of indecipherable secrets from a lost way of life.

Dissipating hums and splashes echoed throughout the night making for broken sleep.  We awoke at 7am and we so no reason to hang about.  It was a few more dry chambers before we came across the next hurdle. A void of a similar size, falling down to a clear, icy lake. Horizontal joists were, once again, held up by two metal rods were bolted into the roof but this time it lacked the bridge it was there to support. Fortunately, a wire aided our crossing. One by one we hauled our weight, hanging from our pulley wheels taking care not to disturb the remaining bridge joist.


The 'Bridge of Death'

The next crossing was aptly named the ‘bridge of death’ by previous accounts. Being only half the bridge of the first, it was relatively easy to see why! It had a single main beam that didn’t even run the full length of the void and a single horizontal joist which was clearly the weakest link. The crossing was unnerving, time consuming and mentally draining but it was passed without incident by all!

We were now faced by a void much larger than anything we encountered previously. A lake so large our light was unable to penetrate to its far shore.   We all stood in a small passageway perched between the ‘bridge of death’ and the ‘chamber of horrors’. Adrenaline washed the tension from our muscles and I danced in place to keep warm.

Along the roof lay remnants of a long bridge, fallen away into the darkness. It was approximately 25ft down to the water and with no clear way forward, SS Explorer made another appearance. Once inflated, we carefully lowered it past sharp extrusions of slate. A puncture now could quickly turn our situation quite serious. The next task involved lowering oneself, bum first, into the tiny dingy. Not altogether impossible but in pitch darkness whilst trying keep relatively silent, it made for tricky endeavour. The penalty for failure was harsh but also not an option!


Crossing the 'Chamber of Horrors'

The crossing was long, approximately 150 yards or more to another wall directly opposite, above which, the passageway continued. Jagged uneven rock made it possible for Scott to scramble up and lay rope for Dean, Ian and myself to ascend more safely.

We sauntered through various passageways making good ground. Our map showed that we were now close to the Rhosyd crossover and an occasional breeze confirmed this. Within 10 minutes we we’re crawling through a small gap in a brick wall that marked the crossing. The wall was an attempt to prevent the two workforces from mixing, steeling slate and using the other mine as a quick exit for the Croseor workforce at the end of their shift.

The Rhosydd mine is in a poor state. There is nothing to suggest it was built more poorly or that the rock strata was weak, but a huge collapse in the 1920’s left a truly massive opening to the surface.  We scrambled up and over the huge pile of rubble formed by the collapse and down into the passageways of Rhosydd. Darkness welled up around us again whilst a resonating crash was heard below, fading before a final crescendo.

We knew that we were still well above the level at which the exit lay and had to descend considerably, below the flooding level in Croesor. Eventually, we found the main incline from which slate was winched down the mine. Where Croseor would haul much of it’s rock up the mine and out of the main exit, Rhosydd would lower much of theirs to the bottom and out via a long tunnel. The name of this exit was Adit 9. This was our escape.


Ruins of the topside mine

We descended as far as the incline would go. Water was flowing along the passageway indicating the direction of Adit 9. Peering down the passageway a tiny spec of light lay at the end with narrow gauge tracks running its length. It was still 20 minutes before we broke through a small waterfall concealing the exit.

We walked back along scared landscape, a rapturous grin forms across my face. I recollect to how unlikely the last 24 hours felt but full of appreciation for a truly real place that cast me entirely under it’s spell.

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