Arizona Mine Rescue

https://www.abc15.com/news/state/mcso-man-trapped-in-western-arizona-mine-shaft-rescue-underway

Looks like a success that ended well - no life threatening injuries. What I noticed was the statement that a carabiner "broke" causing a fall of 40 to 50 feet.

Carabiners don't break; at least biners rated for climbing and used in anything like normal usage. I wonder if an ersatz biner not rated for climbing was employed; some are the same size as real biners and superficially look the same.

Mine rescues are extremely complex, especially when dealing with vertical shafts. They are much more unstable than cave passages.

This is an amazingly good outcome.

A quick look at REI.com shows that both carabiners and climbing ropes are rated to about 7 to 8 kilonewtons (1573 to 1798 lbs) of strength. However, if one of the ‘biners was abused and the gate wasn’t quite right, could that have contributed to a failure? A carabiner failure in that case would be the fault of the climber for not checking his gear.

But then I’m not a climber, my carabiners are for attaching things, not climbing. For my uses a carabiner is a simple over-built convenience.

Carabiners are generally quite sturdy mechanisms. I have a few that are more than sixty years old that still work quite well, although I do not place them in critical locations. More modern biners are lighter for equivalent strengths and can withstand moderate abuse (short of pounding them with a sledge hammer, for instance). Improperly rigged, it is possible for the gate to be forced open which could lead to failure of whatever system the biner was employed, but the biner itself would not be "broken."

More details would be useful. I suspect the victim in this case did not have a strong technical climbing background - venturing alone into a mine shaft is a very bad idea - something never recommended.

Emphasis added!

Too little information in the article.

If he used a figure of 8 with a carabiner; they have been known to be able to brake the screwlock and twist out.

Improper gear or attached it incorrectly can also be an issue

Tjin
Any source for the figure 8 issue, thanks Dave

https://www.theuiaa.org/documents/safety/Karabiner_Breakings_when_using_a_Figure-of-eight.pdf

Wow! Sounds like he's lucky to be alive. Despite making some big mistakes the did one smart thing that saved his life- he told a trusted person where he was going and when he would be back. If he hadn't an archeologist probably would have found his bones in another hundred years or so.

Too bad that precise details are not available. A TV story stated that he "lost control" midway in his rappel,which suggests something other than a free fall from fifty feet up, an event which is usually fatal (as in the cited article on figure eight/ carabiner breakage).

The rigging for the extraction intrigued me - much more elaborate and substantial than the set up we rigged for a similar mine shaft rescue many moons ago (1979s).

Thanks for the link, I was a SAR MRA member for 12 years,late 80’s to 2001. Never saw this data. Great info

Yet another example of how inherently dangerous rappelling can be. No real physical effort involved and it looks spectacular, but about a gazillion things can go wrong, resulting in very bad outcomes.

I believe just about as many fatalities are due to failed rappels, as result from leader falls (at least in Yosemite Valley). Be very careful and check everything before going over the edge.

Two carabiners chained together and then twisted can break. Has happened in lowering a stokes litter.

I have an REI carabiner from 1979 that has a pronounced crack running across the sharpest bend of the d shape. That guy is old enough to own one of those. There were a few Chouinard Biners from that era that were flawed and developed cracks around the gate pins.

MIT study Analysis of Fatigue Failure in D-shaped Carabiners
https://web.mit.edu/sp255/www/reference_vault/Fatigue_Presentation.pdf

Broken carabiner
https://www.osha.gov/doc/engineering/2014_r_05.html

1979? - that recent? I have a steel Gerry carabiner that dates to 1959, as well as a classic Bedayn from the same era. Gates on both still function quite well. Both are essentially retired and looking for a good museum.

Thanks, those links were very elucidating. Point being that carabiners can fail and they may not show any indication of an imminent failure during an equipment check — ...”when the carabiner is un-loaded, all surface cracks completely close”... This makes a catastrophic failure of a “perfectly good” carabiner a possible result after enough cycles. They do have a life expectancy.

The Ringling Bros failure in the second link was a demonstration on how to induce a carabiner failure. The ‘biner that failed was stressed in three directions, but not along the major axis.


It totally makes sense now why the “D” shaped carabiner — the stress is shifted closer to the spine, reducing stress on the gate side.

I have a couple of Army surplus biners. I'm guessing they are WW2 vintage. Both are retired from life safety critical usage, but I still use them to hang gear in my garage.

"old biners never die, they just fade away...."

No, actually old biners just hang in there....

Rappel extensions are gaining popularity. Easier to keep your eye on the belay device, keeps it away from clothing, is easier to use a prussic/autoblock backup, avoids twisting of the carabiner/belay plate or eight to a degree.

https://www.mountaineers.org/blog/extended-rappel-and-updated-belay-techniques

Haven't know any better the last decade. Tying a backup prusik on you leg look is uncomfortable and if not positioned right will open up the leg loop buckle.

As for old carabiners; I just replace them over time. Aluminum doesn't have a minimum threshold for fatigue (not sure if that is the correct English term). I'm slowly upgrading to lighter, stronger and snag free type of gates (keylock for screws or those fancy things for the clippers).

Tjin: “Fatigue” is certainly the correct English term for how metal parts gain small stress fractures over time and lose strength as a consequence.

I’m no metallurgist but I believe you’re correct that aluminum suffers from fatigue at almost any loading (albeit small amounts).

While not practical for mountaineering situations, my favorite rappel device is the rappel rack;

https://www.rocknrescue.com/product/smc-nfpa-long-6-bar-rappel-rack/

Developed in 1967 and enhanced/improved since then, it is safe and relatively foolproof.

Most of my rappels lately have been down sea cliffs abd canyon walls to retrieve fossils, which I suppose is a relatively specialized use - also used by window washers, etc...

Here is one of the first dog leg carabiners. They were a marvel on quick draws when they first came out. Notice how a gate pin at the notch just fell out. I got rid of the batch after that happened.

[img:left]https://blog.owareusa.com/#jp-carousel-1627[/img]

Can't seem to get the image to show. Anyone have suggestions?