Near Miss: Anchor bolt failure incident report.

Before I give the fine details of what happened its maybe key to point out that I am not trying to make any claim or create blame. I do not think that anyone did anything wrong and this is what makes a incident like this even more alarming.
I have the chance to spend most of my climbing time on the finest of choss, placed many bolts in whack trash and even blabbed about "never trusting something without known history, even bolts..." but I certainly never expected to witness bolt failure, especially at an anchor. No one was injured, we walked away that day and went bouldering. The only reason to bring this incident to the community is for shared knowledge and a firm reminder of some things we all already know:

- Climbing is dangerous, Yes, even sport climbing. Gravity is real.
- Many bolts are good, some are not.
- You can climb, clip, whip, hang, and spray all day but certain aspects of climbing are completely out of our control. Even if done correctly.

And obviously me and my partners are chuffer-noobs, it was our fault, and Wer Gonna Die...

On Friday Nov. 27th my partners and I were climbing at the Turtle Wall near St. George. It was cold but sunny and the area was dry. My partner decided to take a lap on the wall classic, Banana Dance, on the right side of the wall. Banana Dance is a route that climbs the underside of a swell and stays very close the ground, almost hilariously so. Terra-firma is always near during the climb and even at the bolted anchor. I would guess that the anchor is no more than 6 meters (likely less) from the ground. After hanging the draws from the ground with the fancy stick-thingy my partner made his way up the route.

The anchor at the top was standard two bolts. The anchor sat in a panel of rock 1 meter from true summit. Right side was a 1/2 bolt, higher with chain. Lower left bolt was a Fixe glue in with two quicklinks. When the climber got to the anchor they quickly clipped into the left of the two bolts at the top. The plan was to clip that first hung draw and then have the chance to hang the second before lowering.

After clipping the left bolt, the climber made several moves higher. Possibly looking for better holds or a better position above the anchor. When the climber got to where the anchor was at mid-body the holds above became sandy and caused the climber to let go. There was ample communication and it was clear to me at the belay that the climber was letting go. I didn't give an unnecessary catch, I remember slightly pulling some slack back through the device knowing that I was going to use my body weight to soften the catch. It was going to be gentle but I certainly did not give any penalty slack for biffing at the anchor before clipping two; No Send!

As soon as the rope came tight, I felt the familiar sensation of protection pulling, belay forces changing, and the sound of rock breaking. As the rope came tight on the bolt below (last protection bolt of the climb) it cause the climber to swing out towards the lower part of the tunnel. Near the apex of the swing/fall the climber made direct contact with a loafy ledge, striking first with heels and then with left butt cheek. Contact slowed down the swinging climber and we were able to safely lower to the ledge/ramp below. After assessment it was clear that it was truly a near miss and the climber was not injured minus a palm sized raspberry from sandstone contact. I believe any extra slack in the system would have resulted in true ground fall and a different style of internet post.

In the first moment it seemed a hold had broken but after feeling the belay forces change it was clear that the bolt had failed. The quickdraw and bolt were still attached to the rope. There was rock and dust scattered below the route.

Upon inspection of the bolt and hardware it was clear that the hardware was not damaged or cracked etc. We noticed that the 'glue' used was not that of an Acrylic based like you would expect. It was not white, clear, tan etc. like standard Acrylic but it seemed to be more like an grainy grey epoxy like that of PC7 epoxy paste. I would even almost describe it as a mortar paste?? I did notice some red stains on the bolt that possibly represents that water had been getting into the hole near the surface. Since it didn't appear that the 'glue' filtered out into the stone I was leaning towards glue-in failure and that the bolt was pulled out of the bolt hole.

Glue-In

Glue-In

When I walked around to the top inspection of the anchor told a different story. It was clear where the bolt had been, there was still ~1 inch of the hole remaining. I could make out a cone in the back of the hole hinting that the hole was likely reused during a re-bolting effort. The whole area below the bolt whole was blown out. The left bolt was closer to a small roof (6inch) of layered sandstone while the remaining higher right bolt sat in a large flat panel of stone. The left bolt was placed within 8 inches of this small roof. It became more clear that the bolt had possibly levered off the rock below the hole causing the failure.

Anchor. Missing bolt hole is 3 links down and 4 inches to the left.

Anchor area

Since there is no way knowing the history of the anchor or what caused the failure it seems that I can only make claimed assumptions. My thoughts/conclusions on the incident:

- The bolt was destined to fail.

- Possibly re-using the same bolt hole during replacement, un-identifiable epoxy, or rock fracturing during drilling or installation could have added to the scenario. Heck, maybe even how the epoxy created different forces on the hole than that of a standard 1/2inch bolt.

- Obvs my partner could have clipped the second bolt at the anchor and got all SERENE with it. This would have possibly protected us, that day, on that lap but it seemed clear that this bolt was destined for failure. Better us, rope swing style, versus some unfortunate college dood that experiences it during anchor cleaning.

- Route was uniquely set up for and incident like this. It is very low to the ground at all times. Possibly any fall while clipping during route could result in ground fall. Falling while clipping same anchor would likely result in the same type of ground fall scenario. So while bolt failure is certainly 'different' I process the potential of risk on this particular route as the same scenario.

- If this was at an anchor of any other standard pitch, away from the dirt, we would have all been laughing and I would be getting free beer and pizza out of the event. But versa this could have been any bolt; that 4th bolt before a gnar runout that you end up punting onto. It certainly will have me looking differently at bolts.

- Inspection of hardware comes with a bit of assumption. I am not certain that I would have initially, in the hype of the moment, noticed upon inspection from the ground or the top that that single bolt was placed in a feature that was likely going to fail. If I would have even noticed such a thing I would have likely fallen back on the idea that "its been used before, its fine". A terrible trap in the game of climbing risk.

- Ill add this tool to the next bolt I place and the next bolt I clip. I think its a positive addition to how I see bolts in rock.

Stay safe and have fun out there!

LIVE SHOW

Having pulled a jug off a route near the top at the Turtle wall I can say that shit is soft rock. I hope the upper bolt/chain/washer combo is about 6" deep or that whole setup is a death trap. That chain/washers combo is an accident waiting to happen too, especially the way it levers out on the bolt.

Nice report, glad nobody was seriously injured.

There is another hole in your photo that does not look natural. Could that be another failed bolt?

Perhaps glue ins are less than ideal for soft crumbly rock. Epoxy needs a dry, debri free hole for it to stick. If there's particles of sand the glue will not adhere. In construction, an inspector is generally called for to oversee that epoxy is being installed correctly. Hole needs to be drilled, blown out with an air compressor, bottle brushed, and blown again.

I don't think a properly cleaned hole (which is extremely important for epoxy) is the issue on this one. It appears to be total rock failure as the whole shear cone of the epoxied bolt blew out...spooky.

Climbing friend jumping spider,

"I felt the familiar sensation of protection pulling, belay forces changing, and the sound of rock breaking."

I am hoping this a typographical error and your sensation of protection pulling and rock breaking is not so familiar. If no, I am being perhaps quite scared on your soft climbing rocks.

I am happy in my heart that you nor your climbing friend experiences the injury, and I thank you posting your story over tubes of internet.

I thought about dust in the hole but didn't think it had much to do with this scenario. If the bolt had pulled out rather than breaking out I would look to see if the epoxy etc. had been affected.

Aleks how proud I am to have caught your attention! I unfortunately am fortunate to have 'friends' who like small gear and moves above them. So I am accustomed to the feeling... My rocks are soft, even I (just like you) can crush some of them under the strength of my own arms.

This looks like another form of galvanic corrosion to me:-)

Jonathan Cunha wrote:I don't think a properly cleaned hole (which is extremely important for epoxy) is the issue on this one. It appears to be total rock failure as the whole shear cone of the epoxied bolt blew out...spooky.

yep, it appears that the problem was that the bolt was placed too closely to the undercut below it. The rock at Turtle Wall is extremely soft, probably some of the softest in the US. That bolt location was never good, but people aren't generally whipping onto it either with it being an anchor bolt.

Just on a side note, it wouldn't be the shear cone of the bolt that blew out because a shear cone refers to when a bolt is placed in a flat wall and pulls out with a tensile force which shears the rock. In this case the bolt pulled from a shear force in the bolt which broke out the undercut rock beneath it. I know it's basically semantics, but even in the soft sandstone of Turtle Wall it would take a lot more force than could ever be generated in a lead fall to blow out a true shear cone.

kennoyce wrote: yep, it appears that the problem was that the bolt was placed too closely to the undercut below it.

Yep. I would also add that the pockmarked remaining glue on the pulled bolt looks like the result of a badly cleaned hole.

Lucky! Good job on the belay, there are loads of people who slack off on paying attention once the leader is at the anchor.

For those bolting in super soft sandstone, both Fixe and Bolt Products make 6" long glue-in bolts (embedded depth, not including the part of the bolt above the rock). That would probably have helped here, although as others have stated the undercut rock below the bolt in such soft rock is sketchy.

I've done enough bolting in very soft sandstone to know that when the rock is really soft, it's simply not possible to clean a hole super well. The hole brush - even a soft nylon brush - will continually dig out more and more sand as you attempt to clean the hole (and constantly increase the diameter - so you can wallow it out to the point where mechanical bolts won't hold). You will never get a "clean" hole. We encountered that sort of very soft rock on the last few pitches of Levitation 29 in Red Rocks - I hand drilled a 1/2" x 3" hole in 6 minutes on lead on the second to last pitch (as a comparison, that would take about an hour in granite). When we were doing that replacement, we were sketched out about the long term viability of any mechanical bolt (we were not equipped for glue-in bolts). We thought that glue-ins would be the only long term solution in soft sandstone, but it's clear that such bolts need to be the 6" long (150mm if using Bolt Products) glue-ins.

Also note that for pro bolts in very soft sandstone, Bolt Products makes very thick 12mm "Crux Monster Bolts" which are made in 6" lengths. To quote their website: "Specially developed for crux bolts in soft rock which are repeatedly fallen on. The flexing of normal bolts can cause cracking of the rock below the bolt which is unsightly and worrying even though there is unlikely to be any serious loss of strength. These bolts are naturally much stiffer than normal and this cracking much reduced."

There are some climbing areas where the rock is just really, really weak. Be vigilant - and as this incident shows, the most important single thing to do is to never clip into a single anchor bolt and go off belay! That goes for any climbing area - even in the very best rock, you never know if one bolt was damaged by rockfall or vandalism or was installed incorrectly or had a manufacturing defect. Take that extra few seconds to clip into both anchor bolts before going off belay!

That's crazy! I climbed this route last fall, and I definitely remember that the anchor back then was two of the bolt and washer with chain connected style as shown on the remaining anchor, no glue-in... The chains were skinny and hard to clip, so it appears as though someone replaced one of the anchors to make it easier to clip....

Side note: You can walk around to the top of this climb and reach over the edge and clip the chains from above...

Scary, and definitely good job not letting your guard down at the anchor.

Hijacking a little bit, but...

Greg, what are your thoughts about how well glue-ins actually bond in that really soft rock? I have no experience placing glue-ins, but having been told clean holes are important and also experiencing that you just can't get clean holes in soft sandstone, i've always wondered how well they actually work.

Another thing i've wondered about are really long bolts in very soft sandstone. I've noticed that on some towers i've climbed that i can't get longer 5 piece bolts to tighten. 3.5" or shorter bolts will tighten, but longer won't. I guess that the outer rock is harder from varnishing, but I wonder if this has ever been tested or if there are best practices.

To add to what Greg said, Bolt Products makes a 200mm bolt using 8mm rod, that's 16mm when twisted. Converted to standard, it's about 9" long and 5/8" in diameter. At that size, bubblegum will hold it in place.

highaltitudeflatulentexpulsion wrote:To add to what Greg said, Bolt Products makes a 200mm bolt using 8mm rod, that's 16mm when twisted. Converted to standard, it's about 9" long and 5/8" in diameter. At that size, bubblegum will hold it in place.

The 200´s are quite popular for the sandstone guys over here, sell a reasonable number of both the twisted leg bolts and the 12mm solid shaft ones. I probably send 50 a year out of the 300´s as well. The normal limit for the twisted bolts is 300mm without having to mess about with the machinery, for the single leg bolts it would be up to 3 metres long. I made a 2m long one once for fun, I´ll see if I´ve a photo somewhere.
The hassle with really long bolts is getting the glue down the hole, you need an extension tube for the nozzle which we normally send out with the bolts or they can be bought from the resin supplier normally.

Sandy holes are better washed out with a squeezy bottle and plastic tube, dry them a bit by blowing or a rag on a stick then use a resin that doesn´t mind water, I use vinylester mostly.
Then put some resin in the hole and with a metal rod rub the resin all over the inside of the hole to dislodge and mix any loose stuff left and wet uot the surface, then fill the hole as usual and fit the bolt.
Better still are the glass capsule systems as the resin is much more liquid and when you install them the glass and the quartz filler grinds into the sides of the hole and makes a much better bond.
For vertically installed top roping anchors we drill the hole oversize (24mm) and use a pourable cement grout.

Alternatively forget the sandstone and find a decent limestone cliff somewhere:-)

Jim Titt wrote: Alternatively forget the sandstone and find a decent limestone cliff somewhere:-)

But Jim, there isn't any good limestone unless you drive at least 20 minutes from this location;)

That has got to be one of the best incident reports I've seen.
Very thorough, well written and I learned a shit ton.
Nice work! glad nobody got hurt!

Hi,
Good thing this was a near miss.

We saw several related issues with glue-ins in soft rock in South Africa.
We found that the TYPE of glue made a HUGE difference in some rocks.
A porous rock needs a more runny glue that can permeate it deeper before it sets.
But in your case, I think even that might not be enough.

Another thing observed in Turkey on limestone cliffs where there is quite a thick "crust" is you need LONG bolts to penetrate down to stronger rock.

And even if the underlaying rock is not significantly stronger, a deeper embedment tends to spread the load.

I'm not sure if a mechanical expansion is a solution here. It tends to load a small part of the hole, and you might still see rock fracture. Maybe with a MUCH deeper embedment depth (i.e. longer anchor).

I'd recommend using some test anchors to determine best solution. You can usually borrow a hydraulic tester from Hilti, Redpath etc. They loan them to construction companies to qualify their anchors. You can do some test bolts at ground level, even on boulders of same rock. But choose BIG boulders.

Good luck.

Alan Jarvis
UIAA SafeCom

I now can remember that there actually used to be three anchors on this climb, and you can actually see the other bolt hole in your picture up and to the left of the one that popped on you, I wonder if there's a story behind it's disappearance as well

As far as the geology goes, the bolts are placed in rock with many horizontal laminations/cracks. The individual beds of sandstone in the band appear to be about an inch thick. This would make the rock less strong. The remaining bolt also appears to be located in layered choss that looks weaker than where the other bolt was. The rock by the jug might be a better choice, as there appears to be less horizontal sedimentary layering (the rock is more 'massive').
Whoever installed those bolts put them in the weakest band of rock in the photo.

Glad you're okay. I am not overly surprised the bolt pulled as that rock looks like crap as do the placements. Why dident the developer place the bolts in the much-more-contiguous rock only 3' lower? I dont see any cracks there, making it far more idea. That would probably be a better option when the route gets rebolted.