Based on zb's comment it does seem that there was progressive failure. There was xtra thread on initial bolting to cater for the potential for the nut working loose (which was a concern given the orientation of the bolt) but not excessively so

The earlier comments on managing softer rock are well made. The point here is that there was no suggestion that there was a problem with the integrity of the rock and that the bolt would be anything other than bomber (and this is with the benefit of experience in bolting in areas of softer rock).

Essentially we are dealing with the third failure in the WC of an expansion bolt (and 2 of them were in dry climate areas). Admittedly, the failures were for different reasons BUT the question is whether any of these failures would have occurred if the bolts were glue-ins.

Right, thanks for the info.
It's quite a tricky clip, so you don't have too much reach (to get to the better rock) - and it's a third and crucial bolt so any lower is no good. Yeah I could try an alternative hole, but it could also potentially spoil the route with a bad placement.
Personally I think slotting in a 150mm would do the trick but I'll get some more opinions before going ahead.

You opening some new routes at Hellfire, or replacing old bolts?

Hi Paddy, howz OZ? So only a couple of threads showing on placement? - Thats completely normal, so it does indeed sound like progessive failure. This could happen in seemingly sound rock. Even when drilling there is only a vague brief feedback to the drill from which to form a judgement, really hard to tell. I strongly recommend inspecting the inside of the hole and not stopping brushing with a stiff nylon bristled brush until dust stops coming out the hole, this should reveal any definite problems. In this case it sounds like things werent that obvious.

Stu:- Nah just gluing some suspect holds on two routes, one is a big flake that could kill so hope to stabilise it. The only concern with putting a long mechanical in the Paarl rocks route is if the ouside rock fails there will be little to hold in the sleeve? Glue-ins are easy to place, if need help just holla - ltrz.

Photo's of bolt as promised.