Anchor: Why did my cam popped out while weighted?

I made an anchor in a vertical limestone flake as shown in the sketch. I was using double ropes. The two figures of eight at the bottom are my tie-in points and those above on the right are my partner's.

I first cloved the right-most piece and weighted it. then I placed the left piece and pulled it tight to weigh it as well. then finished the rest of the anchor. When my partner was ready to lead the next pitch, I placed a carabiner on the right piece to redirect him and as he started climbing the cam popped out. I fell maybe around 30cm as the blue rope stretched. **
I had pulled hard on the cam before weighing it. I checked the spot where the cam was when I was ready to leave and it looked just as good as the rest of the crack. Could there be some dirt or loose rock I didn't see and was pulled out with the cam? Was this a mini- "secondary pull" that made the already marginal placement fail? I always thought "a loaded cam will not come out" Has this happened to anyone?

I wanted to be fast as we were climbing early to beat the midday sun but I probably should have left my tie-in slack and then clove to the master point to avoid the extension and the leader falling on me if he fell before placing another piece and the black cam popped! Lesson learned.

**My partner just said "yep, it happens" and kept climbing out of sight. I cloved the slack purple line to the master point and decided not to move for the rest his lead. :D

Fran M wrote: When my partner was ready to lead the next pitch, I placed a carabiner on the right piece to redirect him and as he started climbing ....

Not your question, but - in theory - the redirect biner can load in a leader fall and damage or cut your clove to the black cam.  Putting the redirect biner on the cam’s integral sling improves things a bit.

I also generally do not redirect a lead belay like that. Too often likely to get slammed into the terrain catching a lead fall and/or for the one piece to fail.  There are alternative ways to use the anchor as a “first piece” on lead.

I always thought "a loaded cam will not come out"

I have never heard that quote and would excise the thought from my brain if it was in there. A marginal placement can hold for a bit and then fail later. Understanding what can cause a marginal placement is of course rightly your pursuit.

A crack that flares larger in the direction of load compromises the camming angle. The designed cam angle is usually far less than 15 degrees. So even a, say, 2 or 3 degree flare significantly compromises the placement. My suggestion is if the crack just looks like it might be flaring in the expected direction of pull, find a better placement.

It is possible the black cam was already marginal for pull in the direction of your weight. But the redirect changed the force direction just enough so it failed due to greater crack flare in that other direction. 

Or, as you suggest, the rock quality (or surface scum) may have been poor enough that it broke away a bit causing the failure? And there was some empirical evidence out there that setting a cam like one sets a nut can improve holding ability. Still, in hind sight, I would not rely on that to improve this placement - especially since you had already weighted it

Great that you are seeking to understand the failure.  Also good for you for focusing more on using the power or master point.  And great pictures - really helps in understanding the config.

Bill Lawry wrote: ...I also generally do not redirect a lead belay like that. Too often likely to get slammed into the terrain catching a lead fall and/or for the one piece to fail.  There are alternative ways to use the anchor as a “first piece” on lead.
I have never heard that quote and would excise the thought from my brain if it was in there.

Bill, thank you for all the great tips.

I did unclip the redirect as soon as he placed a first piece. For alternative ways to use the anchor as a fist piece, I guess you mean, extending my tie-in clove and using the master point as redirect?
For the quote "A loaded cam will not fail" I have surely heard it and read it, refering to a fallen leader, where the holding piece is assumed to stay in place after the fall (climbing magazine article maybe).

I should correct, the vertical crack wasn't such but a huge flake (correct term?) facing right, in the direction of next pitch. The right piece was the upper one.
The red dot is where I made my anchor. the flake was around 4 meters tall. The blue line is the actual route: https://www.cartowall.com/es/route/classica-do-vento/review

Fran M wrote:For alternative ways to use the anchor as a fist piece, I guess you mean, extending my tie-in clove and using the master point as redirect?

Yes. 

For the quote "A loaded cam will not fail" I have surely heard it and read it, refering to a fallen leader, where the holding piece is assumed to stay in place after the fall (climbing magazine article maybe).

It is the opposite of what I think.  Rather, after a leader fall, reinspect the piece that caught the fall before relying on it again. It may have moved into a poorer position and become marginal.

I should correct, the vertical crack wasn't such but a huge flake (correct term?) facing right, in the direction of next pitch. The right piece was the upper one. The red dot is where I made my anchor. the flake was around 4 meters tall. The blue line is the actual route

Good info. Could the flake have moved / expanded a bit compromising the black cams placement?

Fran M wrote: I made an anchor in a vertical limestone crack as shown in the sketch. I was using double ropes. The two figures of eight at the bottom are my tie-in points and those above on the right are my partner's.

I first cloved the right-most piece and weighted it. then I placed the left piece and pulled it tight to weigh it as well. then finished the rest of the anchor. When my partner was ready to lead the next pitch, I placed a carabiner on the right piece to redirect him and as he started climbing the cam popped out. I fell maybe around 30cm as the blue rope stretched. **
I had pulled hard on the cam before weighing it. I checked the spot where the cam was when I was ready to leave and it looked just as good as the rest of the crack. Could there be some dirt or loose rock I didn't see and was pulled out with the cam? Was this a mini- "secondary pull" that made the already marginal placement fail? I always thought "a loaded cam will not come out" Has this happened to anyone?

I wanted to be fast as we were climbing early to beat the midday sun but I probably should have left my tie-in slack and then clove to the master point to avoid the extension and the leader falling on me if he fell before placing another piece and the black cam popped! Lesson learned.

**My partner just said "yep, it happens" and kept climbing out of sight. I cloved the slack purple line to the master point and decided not to move for the rest his lead. :D

Your placement was bad and your double rope anchor is a mess. Go with cordelette or just one rope in the anchor.

It is the opposite of what I think.  Rather, after a leader fall, reinspect the piece that caught the fall before relying on it again. It may have moved into a poorer position and become marginal.

Oh, I meant: while it is still weighted, right after the fall. So one could rest, calm down or be lowered confidently hanging from the loaded piece. Hope it makes more sense now.

Good info. Could the flake have moved / expanded a bit compromising the black cams placement?

I hope not! The flake was massive and solid (tapped and kicked it) but it is still a possibility.
From the options you suggest I think the poor surface rock quality or surface scum makes the most sense, as the redirect was not really loaded and the flake seemed solid.
How to avoid this in the future? pull harder after placing the piece? In different directions? carry the headlamp on the helmet and inspect the inner surface of the flake? hit it with my nut tool?

Tradiban wrote:

Your placement was bad and your double rope anchor is a mess. Go with cordelette or just one rope in the anchor.

I hesitate taking someone suggesting a thngalette seriously..
 but making the anchor with one rope might make more sense on the master-point tie-in version. I build the anchor with with both to keep a longer length available to the leader. Also cause I am hanging off two points as soon as I have placed two pieces and I can call off belay and finnish the anchor afterwards.

Fran M wroteFrom the options you suggest I think the poor surface rock quality or surface scum makes the most sense, as the redirect was not really loaded and the flake seemed solid.
How to avoid this in the future? pull harder after placing the piece? In different directions? carry the headlamp on the helmet and inspect the inner surface of the flake? hit it with my nut tool?

If it was not a placement in a flare (even slightly) and the flake was solid, I don't have a good answer other than “setting” the cam to improve the metal to rock contact  ... which is neither a very inspiring answer nor should it be.

I mean, I suspect there is some other reason why it failed. I feel you/we just don’t really know why yet.  Perhaps an indicator to seek more input on your placements and surrounding rock from other experienced partners? It is puzzling.

Bill Lawry wrote:

If it was not a placement in a flare (even slightly) and the flake was solid, I don't have a good answer other than “setting” the cam to improve the metal to rock contact  ... which is neither a very inspiring answer nor should it be.

I mean, I suspect there is some other reason why it failed. I feel you/we just don’t really know why yet.  Perhaps an indicator to seek more input on your placements from other experienced partners?

The flake width was not homogeneous, but at this point I can't remember any more details. Only thing that comes to mind is a comment form a guide on a bolted route next to us, who said he had tried the route but bailed because all the placements where so dirty. We didn't find so. Chossy, yes, but its not a route done very often.

I agree though there is something I am missing. I think this is a fairly big mistake. Specially as I was hanging off that piece only (even if still on belay) at least until I placed the left piece. Definetely need more feedback on my placements. Will do, thanks again  for your insight.

Thanks for posting the question, Fran.  Takes some courage. I think you’ll work through this and come out the better for it having happened. :)

Of course it is difficult to say from a photo, but that rock looks like crap for placements.  Any flake is suboptimal for placing gear because flakes can and do expand under load. But the flake where you placed your dot has a fracture line almost completely around it. Most of the rock in the photo looks semidetached. 

Bill Lawry wrote:

.......Could the flake have moved / expanded a bit compromising the black cams placement?

this^ .....and its limestone

The words jumping out to me are "cam", "flake" and "limestone". Flakes pose certain issues, which have already been mentioned, and passive pro is thought to generate less outward force than a cam which can lessen the problem.

Cams in parallel limestone cracks can slide out, unlike placements in most other rock types. The rock surface can vary considerably, so maybe the cam walked from a secure placement to a poor placement. Generally you want to place cams in some sort of constriction or pod in a limestone crack, and treat cam parallel placements as suspect.

Big B wrote:

this^ .....and its limestone

Yes, exactly this, flakes tend to flex and open up under load, but the biggest issue is that you are using cams in limestone.  Limestone is a very low friction rock type, I have pulled textbook placement cams out of limestone with a hard tug.  Obviously that doesn't mean that every cam will pull out of limestone, depending on the geometry of the crack and the local friction of the rock, they may hold just fine, but you have to be extra careful with cams in limestone. 

my gawd that looks complicated.  Two or three slings and your done, without fail, without worry

Pitches 11 and 12 on RNWF probably used to look solid at some point too. My friend who has been climbing for a few years had 5 cams pop out of splitter granite where thousands of cams have been placed and not popped. Maybe you need to re-evaluate you cam placement technique like he does.

Fran M wrote: I made an anchor in a vertical limestone flake as shown in the sketch.

I stopped reading there, because you had already answered your own question.

B, David, Ken, Jaren: thanks for the comments. I am aware of the particulars of limestone but hadn´t considered the massive flake expanding. A quick search returned:

https://rigginglabacademy.com/building-anchors-spring-loaded-cams-pull-test-using-metolius-camming-units/
Be extremely suspicious of placements behind flakes or blocks. As we said before, cams exert a tremendous amount of outward force in a fall, so they can expand or even lever off even seemingly solid flakes or blocks. Passive protection is often a better choice behind flakes or blocks.

If anyone has some good resources, I will appreciate it.

Adam, I guess you refer to the rope anchor? give it a try. Then tell me if its complicated... Using slings, sounds like the thingalette above.

John, what do you mean "re-evaluate like he does"?  

i guess if the placement geometry was theoretically good (though i also think it was the large flake moving), then it would have to be a friction problem.

the only time i had a weighted cam pull out, i was doing some self-rescue drill on the ground. after some random weighting, a cam popped out while weighted. it was placed in a slightly flared crack with some lichen. no friction. it was funny since it was no-consequences, but i'm glad it happened then so i could see just how important it is to account for friction.

also, since presumably all cams were placed in this flake, maybe a good takeaway is diversifying anchor placements to utilize multiple features. especially using double ropes and rope anchors, that should be more doable.

Fran M wrote: 
John, what do you mean "re-evaluate like he does"?  

I mean, he thought he had good placements and was a very competent and experienced trad leader. He then had 5 cams zipper out of serenity crack on the crux pitch, which has ideal cam placements. He went back and relearned how to place cams because he realized he was placing a lot of tipped out and overcammed gear, which is not full strength. Also, having all your gear in one feature that you have to pound on to check should be a red flag as well. I recommend taking a peek at the huge pack of paper that comes with every cam (also online at https://www.blackdiamondequipment.com/on/demandware.static/-/Sites-bdel/default/dw4ed898ac/instructions/F16/MM5865_F_Camalot_IS-WEB.pdf) and go back to books like the john long Anchors book and peruse the chapter on gear placements again. It may seem like beginner stuff, but giving yourself a checkup on basics is healthy and prevents development of sloppy habits that put you in a pickle. Maybe go do a couple pitches of C2 aid too, it helps a ton.