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Report - - Llanberis (Dinorwic) Slate Quarries - Llanberis - May 2015 | Mines and Quarries |

Report - Llanberis (Dinorwic) Slate Quarries - Llanberis - May 2015

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The Lone Ranger

Safety is paramount!
Staff member
Llanberis (Dinorwic) Slate Quarries – Llanberis


The lowest slate quarry lies just outside Llanberis (100m A.S.L.) on the shore of Llyn Padarn, Vivian Quarry is just slightly detached from the main area, a few 100m away on the shore of Llyn Peris, rising to 650m above sea level, that’s 500m or 1500ft in height and probably 3 miles width.


Llanberis slate starts around 500 million years ago, when layer upon layer of mudstone - deposited over millennia in a shallow sea - eventually became overlain and intruded by volcanic rock, lava and ash. The heat and pressure that these applied to the shale type rock, transformed it over aeons into what is now considered the best slate in the world.

Slate is virtually impervious to water, and is easily split into tiles making it excellent for roofing. Post formation the slate lay dormant for another age waiting for the next event in its long history - the collision of what is now the UK with Nova Scotia caused the mountains to rise above sea level and the Snowdonia mountain range was born.

And there it would have ended for the slate, buried under a mountain of rock, but the earth had different ideas and around 100,000 years ago the earth was plunged into a glacial period - glaciers shaped the landscape of North Wales into the dramatic mountainscape that we see today. Jump forwards to 10,000 years ago and the globe started to heat up, the ice retreated and the world we know today started to emerge.

Whilst limited mining occurred in early times - the most notable a Roman fort who's remains on the outskirts of Caernarfon was roofed in slate - it wasn't until much later during the industrial revolution that slate mining expanded rapidly. Factory building and rapid urban growth led to the need for an effective roofing material, and that's where slate and the Welsh quarries associated with it came into being.

In 1890 the industry peaked, with over 17,000 men being employed in the mines and quarries of North Wales. The subsequent decline in the industry was to have a major effect on the locals and workers alike. When, in an effort to employ its workers with disregard for new Health and Safety Laws the owners of the quarries essentially locked the workers out for nearly a year with no pay, times became very hard and when the mine owners eventually opened the gates to the capitulating workers, they only took on half the original workforce.

Similarly it is only just coming to light after the Penrhyn family finally released historic papers from the time - after the last living relative of those times passed away - that the owners not only kept the welsh workforce in poverty, but used the ships that transported the slate all over the world to engage in the slave triangle. It was this transportation to global destinations that gave birth to some of the names of the areas in the quarries, however it has been suggested that some of these have been misnamed by climbers, although the general theme is still there.

After the Second World War new technology in roofing, which was cheaper and easier to manufacture than slate was born - the ceramic tile. So despite more mechanization the quarries went through a steady decline until in 1969 when the Dinorwig quarries finally closed. By the end of the mining in Dinorwig, 362 quarrymen had lost their lives extracting the grey gold.

My Visit

I first visited these vast quarries in the mid 80's, not to explore so much, but to climb on a rainy day when it was not possible to get out on the mountain crags, slate dries in minutes so it was possible to climb between showers. During the showers we did venture down the odd tunnel, into outbuildings and enjoy the unique environment we had ended up in.

Here's a photo of us exploring the quarries in the late 80's, this is still one of the classic routes of the Quarries, called 'Comes The Dervish' E3 5C.


Day 1

Enough of the history and on with the photos, I do like these quarries if you couldn't tell. That much so I decided to spend a couple of days here and visit the whole place. Photos are just in the order I found things, day 1 in the Northern half of the quarries.

Straight into a couple of adits as you enter the quarry; nice as it still has the 2ft gauge train tracks at the entrance.


The tunnel splits after a 100 meters, the exits terminate about 100ft above the base of the quarry.


The weather was getting worse, visibility down to 30 meters making navigation interesting between the levels, this is looking down on the old buildings as I continued to climb one of the inclines.


Visibility got worse, but found a track I had hoped I'd find, this went for over a mile to something I'd seen on a map. It probably would have been interesting if I could have seen it as it was a Surge Pumping Station for the Hydroelectric Power Plant, alas a big electric fence put me off taking a close look. I dropped back down to what I hoped would be the top of the quarry, and found a side tunnel to the Hydro Scheme alas it was gated.


Was a good looking tunnel as well.


The visibility was horrendous and was trying to pick a way across to the opposite side of the main quarry, I didn't know if any of the levels linked up and couldn't see if they did, the good thing was I had to visit each level and pop my head into all the buildings as I passed, lots of small hidden gems to see. Liked this small hut as it seemed to be perched just on the edge of the abyss, had no idea how far the drop below was at the time.


The first of what would be many tramway waggons perched on the edge with the hut sat on the abyss in the background.


The cloud decided to lift giving me glimpses of where I'd been, where I was and where I actually wanted to be. The level I was on at that time was good, plenty of old buildings. I was at this point also wondering where all the wheel had gone from the waggons, not one to date had any!


Once the clouds cleared fully this was my view, I'd basically looked at everything on the right hand side and what lay above me and around the corner on the right side. Where I wanted to go was the left side of the quarry.


I essentially had 3 options now, back the way I came and across the top hoping the cloud didn't descend again, traverse out right and head down and climb back up the left side or just descend the huge scree slope below trying to trend left. Option 3 seemed the most fun (easiest) option, what's the worst that could happen? I've descended plenty of scree before, but this was special scree, the whole hillside moved down with you, it didn't stop moving even when you got onto the bigger blocks lower down, the noise was immense, trying to move diagonally away from the main flow being the only way to avoid being enveloped by the flow of rocks. I briefly remember looking down at a group of climbers who were looking up at me and pointing, I must have made an impression as they asked a few hours later when I bumped into them again if I was that nutter on the scree slope, I just grinned.

Once things stopped moving I had a quick pop into these nice buildings, just right of centre in the previous photo.


The left side, a few interesting buildings here, some graffiti and the realisation I would somehow have to head upwards at some point to connect with a level to get me back on the proper side of the quarry, something to worry about in a bit.


This is getting back into the central area where most folk visit, some nice buildings and workings here.


The cradle of an old Blondin aerial ropeway dangling on the wire rope.


Crunch time, scree or ladders to ascend up the various levels, I'd had enough of scree and what's the worst that could happen on the ladders? glad I couldn't see what secured them when I started up them!


I found the tourist bit, old boots and jackets. Plenty of names, a real shame all the recent ones are so huge ffs!


Heading back down after the first day, pass one of the inclines.


Day 2

An early start the plan was to visit the Southern half of the quarries, the area where the quarry spoil was moved to looking at the maps.

Plenty of spoil and waggons without any wheels again.


The lack of wheels wouldn't have been a problem for the waggons on this track as it is the end of the line.


Looking back down the quarry at one of the towers which supported the overhead ropeways.


Many of the buildings have hidden gems, I did like this also a fair bit of 1950's graffiti on the walls.


Back to the wheel less waggons, with what would be Snowdon on a clear day in the background.


A couple of tunnels on this side of the quarry.

Getting back towards the central area again, I'd seen photos of these before so was glad I finally found them, think there's 34 of these slate dressing machines in this shed.


Well worth the 2 days mooch to find these and the next set of buildings, possibly I should have just done the tourist trail.


This is the next set of buildings, just before you get back to the main quarry.


Thankfully they are still a fair stroll for most folk so they remain in a good state.


Plenty of sheep shit on the floor, but still a fantastic place to visit.


And a final photo as I drag myself away from the quarries.


Well that's it, the phone app said I did 20 miles over 2 days, 5000ft of ascent. I just had a good time, somewhere I had wanted to have a proper look around for many a year and I was not disappointed.


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28DL Full Member
28DL Full Member
Great report, learnt a bit on the geology!

Went up here with my wife a couple of years ago in much nicer weather! We have a rather nice slate mat on the table as a souvenir, I know it's not the done thing but among the many millions of tonnes of slate waste I didn't think they'd miss it!

What it's hard to explain unless you've been there is the gobsmacking, unbelievable scale of the place!!

We were speculating what the score was for working on the upper levels, as it would take a significant chunk of the working day just to get up there!!

We got some great photos of some RAF jets in the valley below us, but sadly I've lost them!!

The Lone Ranger

Safety is paramount!
Staff member
Cheers all, I did enjoy this wee stroll, something I'd wanted to do the full for many a year :thumb

Great report, learnt a bit on the geology!

What it's hard to explain unless you've been there is the gobsmacking, unbelievable scale of the place!!

We were speculating what the score was for working on the upper levels, as it would take a significant chunk of the working day just to get up there!!

I'm sure they won't have missed the odd bit of slate, I had a few in my boots after my encounter with the scree slope ;)

It did pass my mind the workers walking up and down to the levels each day, I'm sure some must have lived up here and others rode the slate carts up the inclines to get to work in the morning.