I recently popped into Aberllyn to test some of the anchors and replace several that have failed on the easy traverse on floor 3 of the mine (the traverse hanging wall side to the pillar in Cathedral stope).
If you see any green cable ties on the anchors it means they’ve been pulled in axil (directly out) up to 6kN for 30s. Not all anchors were tested but certainly the important ones on the first few pitches were.
Most of the anchors that failed were DIY type anchors with proper hangers. In most cases the outer sleeve had almost completely corroded and they pulled out with very little (less than 1kN) effort.
One of the anchors at the head of the first pitch failed at around 2-3kN, turned out it was a bit of threaded bar that had been resined into place, and by the looks of it the bond between the resin and rock had failed. This was most likely a result of not managing to clean the hole properly which is not an easy thing to do in the mud-stone of Aberllyn.
A little worryingly a 12mm Coeur (expansion) anchor failed at around 4-5kN. This was one at the start of the traverse across the footwall side of the Cathedral Stope. Turns out it was in very soft rock which just crumbled on extraction. A resin Collinox anchor replaced it and was tested to 6kN.
In all 7 new anchors were placed. The traverse rope on the hanging wall side of Cathedral Stope was removed, with the fixed bit of rigging left to traverse around the pillar, so if you want to protect yourselves on that easy traverse you’ll need around 25m of rope and 6 krabs. It would be nice not to see a fixed rope placed there so it can be rigged if necessary.
The rigging guide for Aberllyn remains unchanged.