Ogof Craig a Fyynonn entrance

[Babyhagrid]

Does anybody know if there is a long term plan about the entrance of Craig a fyynonn. I was there yesterday and the roof looked very fragile with stacked fallen rocks below. We took care not to hang around underneath this area as per the advice, but it made me think, is there a plan to remove the hanging death rocks or just to wait till they fall on their own and then deal with it afterwards?

 

[alastairgott]

As far as I recall from my first visit there 13 years ago there was a warning about the rocks. And we made sure we didn’t hang around the rockface. Sometimes with gardening you make the problem worse, by pulling away rocks you weaken the rocks underneath.

Don’t have my copy of selected caves on me right now but think we could have been using that for our visit and it may have carried the warning about the rocks.

 

[Babyhagrid]

Ogof.org states "A large quantity of rock has fallen from the cliff above the entrance. There is still more rock that is likely to fall, great care should be taken on entry and exit." So we were well aware. However I was wondering if the Mynydd llangattwg cave management committee had a plan for the future of the entrance as additional rockfalls seem inevitable over the next few decades.

 

[Stuart France]

MLCMAC are not planning to modify the roof/cliff above the entrance. The problem is where do you stop once you've started. In any case, falling down is in the nature of caves. There are other caves in the same area with similar roof issues, for instance Siambri Ddu, Ogof Capel, and Chartists Cave. It's not only the roof but the floor too as we all know from the large rescue job in OFD last year.

Walkers too face rockfall risks. The footpath through the Craig y Cilau NNR runs parallel to the quarried cliffs above and there have been some spectacular landslips in past decades, as well as rocks falling off and landing on the track - anything from tens of kilos each to tons in weight.

My suggestion in such situations is to go one person at a time and not to linger under or on anything that looks unstable; a bit like crossing a steep couloir filled with snow, maybe with loose rock above that may or may not still be frozen, as mountaineers know all too well.

 

[Stuart France]

Another rock, this time about the size of a bucket, has fallen out of the roof and landed in the new drainage trench outside of the gate was discussed in the other OCAF Access thread. It's been moved of course, i.e. the rock not the thread.

 

[alastairgott]

A big bucket or a sandcastle bucket? 🏖️🪣♠️

 

[Stuart France]

A domestic bucket, not a JCB bucket.

"It's not safe outside the cave" as Game of Thrones puts it.

 

[Badlad]

I have a distant memory of a trip to CaF with the Hereford CC. Whilst we waited around by the entrance for the keyholder a few of us checked out a cave entrance a bit higher up. It had a draught and looked a really good dig. " That'll just connect into the main cave", they said. I was just wondering if that entrance would be a safer way in - if a dig was successful there?

 

[Stuart France]

From what I've seen, it is horribly looser. Unfortunately the whole cliff face is falling to bits and unclimbable: case of putting back your brick sized hand hold after you've used it. Geologists will probably laugh at me, but I think the "bricks" are from cryogenic action. Never mind microscopic cryogenic carbonate dried out puddles inside caves that are the academic focus these days, what's happened at and a short way below the surface is much more dramatic.

I've seen perfectly formed limestone "bricks" going down 10 metres in a dig not that far away, so regular in shape you'd think they'd been put there as neatly stacked quarry waste, no mud infill, and looked like they were cut with a machine, until the penny drops that it was ice that did this. Below 10 metres it was proper phreatic passage.

So it's fortunate that the roof beyond the OCAF gate is pretty solid and at the logbook the "brick" stuff is at an end. Your next concern should be the first boulder choke which seems to be supported on rather too much fresh air and the shuttering is bulging...

 

[Babyhagrid]

.
Your next concern should be the first boulder choke which seems to be supported on rather too much fresh air and the shuttering is bulging...

Out of interest, who is responsible for placing the shuttering onto that scaffolding. Looked like failry new plastic stuff. Not the usual slimey wood that usually haunts bolder chokes. I'm sure some of the rocks that are weighing on the choke could be moved out of way. Especially the ones that sit directly on top of the route. However don't want to go treading on anyone's toes if they're already looking after the scaffolding there.

 

[Stuart France]

There's a huge amount of perched boulders sat on top and around the sides, best left where they are and not disturbed I think, and with nowhere else obvious to put them, and a lot of water going through all this in flood to emerging at the small space containing the fixed ladders.

I don't think anyone is going to mind if someone volunteers to beef up the scaffolding by adding more tubes on to the existing structure, but the right approach would be to contact the MLCMAC first for a discussion about it.