Are your bolts what you think they are?

Interesting stuff. So far as I know all the BCA approved resin anchors are 316, but exploration bolts and privately placed bolts could be 304 or, as in the first link, 303 sold as 304. It's suggested that part of the reason for the failures of the bolts in the second link was the stress on them from installation. Long term, that could be an issue for all mechanical expansion anchors: a brittle failure, and could be harder to detect than loose resin anchors. Maybe drilled threads (Abalakov if necessary) are the way forward?
 
I've seen a few Abalakov /:threads fail , or been the verge of failing and a few that had to be rejected after drilling. When they work all is good but sometimes the cave is left in a right mess.....probably not the best option.
 
Note that both of above were in high chemical reactive environments (sulphate and chloride)

I don't think we need to worry as much except for metal mines & sea caves (but worth knowing)
 
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