[Nmcaver] Pryor Spring Cave Rescue, TN

[Minton, Mark]

>If these guys had years of caving experience, how did their rope, or knot, "just fail"?

      That was exactly my question.  Apparently the knot deformed and passed through a descending ring.  Here is part of a detailed report someone sent me:

>The cave is a pull-down trip, whereby one sets each drop for a rappel, once all members have descended, the rope is retrieved by pulling it down.  The method used was a jammer knot against a SMC Descending pull down ring.  I tied a triple over hand knot with a single figure 8 knot  backed up snugly to the overhand knot.  The rope used was a 10mm E-Z bend.
>
>At the first pit (~45'-50'), there is a chain pull down station on the right wall.  You rig the rope there.  This knot & rope had been used on 3 previous trips in this cave in this knotted sequence.  This was to be a "routine" 1-2 hr., a trip I have taken several people on before.
>
>I rigged the rope into the pull down station as mentioned above.  Rick was to be first down, to catch the retrieval cord bag & help to hold it out of the way as I came down second.  We would then pull the rope with the retrieval cord & bring the rope down, taking it with us to the next drop.  This is known as a pull down maneuver.  A pull down trip is a special circumstance sort of cave trip requiring the cavers to commit to finishing the trip after the first rope comes down.
>
>Rick approached the lip & clipped his safety tether to the chain station.  He inspected the knot I had tied & I could tell by his look that he wasn't 100% about it like I was.  I noticed this & decided to give him extra piece of mind by tying an additional knot, a figure 8 knot, which I butted up against the "barrel knot" end to provide even more girth.  This knot appeared amply huge enough to jam this ring to satisfy both our rationals about how this kind of system was suppossed to work, and with over 52 years of combined experience at height between the 2 of us, we agreed it was good.  Rick rigged in, weighted the system, tested it, unclipped his safety tether & began his rappel.  I backed away from the edge & got my system ready to go down. I glanced up & all of a sudden all hell broke loose.
>
>I heard his yell & I focused in on the knot as it popped through the descending ring.  I noticed the retrieval cord go zipping into the chains as they recoiled up into the air about a foot.  I stupidly grabbed for the cord, hoping for something, I'm still not sure what for, but I did.  I heard him land & yell out.  I lost the cord as I watched the reflective cord disappear down the drop and coil up on the bottom.  I yelled to him & he responded.
>
>He had fallen a distance as best I can tell as the only witness: about 30-40ft.
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      Hard to believe that could have happened with a decent knot.  That's not the way I would have done a pull down, and I certainly won't try it in the future!

Mark Minton
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