Report - Rhosydd Slate Quarry - New Years Day 2018

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28DL Full Member
28DL Full Member
May 17, 2015
Hi, all I have been lurking around for a while but now it is time to make my first report. Recently I have become interested in old mines, living in Derbyshire I have quite a few mines within an hours drive but they all seem to be a crawl around in sticky mud type of mine bar a select few.
Rhosydd is the mine that got me really interested into actually going into mines after I saw it on a walk up Cnicht in 2016.

Some History:

There are many mines around the Blaenau ffestiniog area, some with miles of tunnels and huge chambers, some rather more modest workings. Rhosydd is on the smaller side (even though it has some 170 chambers!)

Slate was found on this site in the 1830s by two men from Croesor who then applied to the landowner for permission to quarry there, this led to confusion of who actually owned the site as there was no clear border on land which was no more than boggy moorland. Major work began in 1852 but there was problems with getting to slate down the ffestiniog railway partly due to the terrain and partly due to their rivals (Cwmorthin Quarry) being difficult. To begin with they had to use pack horses eventually moving on to the Croesor tramway in 1864. In 1900 there was a huge fall which destroyed the South- East workings killing many men - this part is slowly becoming more accessible but I didn't visit this trip. The mine closed in 1930 after removing 222,000 tonnes of worked slate and some 2.5 million tonnes which remain in the tips.
(Hopefully my grammar wasn't too bad! I was trying to not just copy off the wiki.)

The Trip
As it was a 3hr trip to Blaenau it was an early start, 4.30am on New years day. Rather unsurprisingly there was no one about, presumably still pissed from the night before but it did make for a rather fun drive. The weather was typical for the time of year (rain of course) so we did wait in the car for 30 mins or so until it stopped. The original plan was to do Conglog, Rhosydd and Wrysgan in a big loop - I do have some pictures of Conglog but dropped my camera in a bog before we made it to Wrysgan so no pictures!

I also texted my dad to call cave rescue if he didn't hear from me by that evening, rather unfortunately I forgot to tell him where we were and I didn't have any signal for the next 9hrs :banghead He did say he was very close to calling them when I got back. ( I did tell him 9pm and we got back to the car at 16:30)

Anyway some of the pics:

This is one from 2016 on the Cnicht circular showing the surface buildings and tips. Im not posting anymore surface pictures as there is loads floating around the internet and I don't want to make this report too long.

This building was for a 40ft wheel but was never used, some arguments over water rights I think.

The main transport hub at the end of the 2000ft+ adit number 9

Complete with sheave that can still rotate after all these years.

A Trwnc at the bottom of the 5/9 incline. I heard a small stone fall down while I took this picture which almost made me shit myself!

Flooded chamber directly west of the incline on floor 9. There is a further 4 floors below which are now all underwater.

A look down the incline with the Trwnc at the bottom.

A big collapse in what I think was floor 6, this also blocks the top of the incline but ironically means you can climb up it to the next level.

Climbing up to the next floor, plenty of room to get through.

Floor 5Now into day light coming in through the bottom of the twill. The tramway ran along here ....

.......and across a bridge which has collaspsed.

The sheave for the 3/4 incline in the Twll.

In the bottom of the Twll. some rather large pieces of rock have collapased inwards.

Heading now to the east workings where the great fall occurred. Some storage boxes still stand along with some bolts for some machinery.

Part of the great fall. There is possibly some 50 chambers all caving in like this. Some bodys were never found but we didn't see any skeletons!

The internal incline in a chamber at the end of adit 9. Runs parallel to the other incline.

The same room from a different angle.

The only real disappointment (apart from my camera going for a swim) was that we couldn't find the 3/6 incline, all I found is a chamber with a collapsed bridge hanging off the roof.


Staff member
Nov 24, 2008
Good effort that, there is a couple of bits that look like about to collapse every time I've passed, makes for a good through trip into Croesor, but needs more experience and gear etc so please be careful with this place :thumb


28DL Full Member
28DL Full Member
May 17, 2015
The camera survived the mine just not the walk around to Wrysgan. When we in to Rhosyd it was fine outside but came out to 60mph gales! I stepped in some water which went straight to the top of my wellies and I fell over :confused:

My cousins phone died end up in the stream running down the adit but everything still works