There’s been a history of bolt failure in Aberllyn over the years. In 2010 Miles and I placed a number of bolts, one in particular (a 16mm resin Battinox bolt) was placed and used after the resin had set (around an hour) only for us to find a few months later it could pretty much be pulled out of the rock!
It was around that time we bolted a long pitch from floor 1 down to floor 4 with a perilous take off from some old beams. I recently checked the bolts having heard that one or two had failed, to find that someone had clearly pushed the bolts back into their holes giving the impression they were sound, only to find that they could be pulled out by hand! The anchors that failed had been in place to protect the traverse to the pitch head.
Closer inspection shows that the bolts had corroded inside (I’m pretty sure the bolts that failed were not PPE bolts, but RAWL anchors) with the expansion sleeve pretty much dissolved!!
Stay well clear of that top pitch, we recently pulled all but 2 of the bolt out by hand leaving a wobbly 16mm Battinox anchor in the roof and a rocks crew deviation only. The other bolts in the mine seem fine but I’d be giving them a good tug and twist before committing to using any of them.
Here’s some photos of the bad bolts…