Breakdown breaking down

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Breakdown breaking down

Postby chaz » Oct 9, 2005 10:55 pm

I wonder how much shifting goes on in a cave when no one is around. (kinda like when a tree falls in the woods does it make any noise) A large slab in Doghouse cave (Missouri) has aparently dropped from its known position. Cavers have been crawling under it for years! Fortunately, no one at that moment. they say you can still go under it, or over it now. Today, in Fitton (Arkansas) With a group of competent Experienced cavers, as we all followed a well traveled mud path, A huge stone toppeled in the trail narrowly missing a fellow caver. I've never seen anything like it. Sure I've seen breakdown teeter and slide or rocks loosed on a climb but this thing had been a handhold to steady many a caver over the years. It could have easily been a fatal accident. Now it's a stepping stone and we cave on. Does anyone have a similar story?
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Postby Plethodon » Oct 10, 2005 7:55 pm

In 1992 was campin in sandstone cave in American midwest. Was sleeping. Pretty far into the cave. Middled of the night--KaBOOOM,,boom,,,boommmmm. I wented back to slepp. In the next morning one girl with us said, Anybody hear the big crash in the middle of night?" Only she and I heered the rock drop and roll. Because room had much breakdown between entrance and our camp, we never found rock. But heard it! Oh boy!
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Postby kelly » Oct 10, 2005 8:53 pm

I was cave diving in Jackson Blue once and something dislodged from the ceiling while we were in the tunnel. The amount of silt it stirred up blew out visibility all the way to the cavern. I've been in a couple caves where the guide line disappears into some breakdown,and I know the people laying the line didn't put it there-makes you swim fast and hold your breath.
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Postby Ralph E. Powers » Oct 10, 2005 10:49 pm

We were digging out a cave and doing a right good job of it. At one point in the large room (for that particular cave) there were some slabs stacked and leaning against one wall. Now they would've NEVER probably moved at all if left well enough alone.
Alas one of the diggers said that he was feeling some great air coming out of where he was digging... the fella behind him got a bit over zealous and sadly careless, he started tossing the rocks handed to him where-ever... the room was formationless, and several of them hit those slabs... pretty soon there was an ominous crunching sound of rock sliding on rock... needless to say all of us got out of there in a big hurry.

Came back couple weeks later and shore enuff... those immovable slabs if left well enough alone slid and slided to a nice pile... right where we were diggin. :roll:

Turns out it was a convection air-movement and we found the source on the opposite side of that room... now we're blocked by solid rock above and below and all around... the hole where the air is a blowing (hard) is about the size of one's head... SIGH...

anyone spare a couple of "cave expanders??" :D
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Postby cob » Oct 13, 2005 6:59 pm

Don Rimbach and I almost got crushed by a "buick" once while diiging in an ugly little mud hole in south st louis called "bailey pit"... great story(picked me up, slammed me against a wall and dropped me on top of him and one other guy).

After Don's recent death I posted a "version" of it (I am admittedly a little foggy on some of the details... 20 yrs ago) on mocaves.

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Postby JackW » Oct 14, 2005 8:28 am

cob wrote:After Don's recent death I posted a "version" of it (I am admittedly a little foggy on some of the details... 20 yrs ago) on mocaves.


If you've got it still or can find it, please post it. Sounds like an interesting read.

I was exploring the top of a breakdown pile that went about 30' up to the ceiling of a room is a cave in Southern Indiana about 6 years ago. As I stuck my head up in to what looked like a lead with nice air movement, I brushed a boulder, bearly touched the thing, and it went screaming down the pile towards my two friends at the bottom. I'm half into this hole at the top screaming "ROCK!!!" as I hear this thing ginding its way to them in a hurry. I droped out of the hole and looked back for them. They saw it coming and as one put it, "I'd never moved so fast in a cave before". The rock was about 1' thick and about 2'x2'. They asked why I didn't yell rock; which I had. I figure no one can hear you yell "rock" with your head up a hole. :lol:
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Postby Sean Ryan » Oct 17, 2005 11:21 am

I wonder how much of the breakdown movement can be attributed to the presence of cavers. It seems too much of a coincidence that this giant overhanging chunk of rock decides to collapse during the one hour a year that people are walking under that chunk. Maybe the walking disrupts some foundation rocks, or it's so precariously balanced that soundwaves or increased body heat will break it off.
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Postby speloman » Oct 17, 2005 11:35 am

Human Impact can always be a factor. But Break down happends all the time. It could be just being in the wrong place at the wrong time. There is a cave I usually go in once a year and every year I have been there I have notice new break down. Not alot, but enough to keep a eye out. I havent been there for 3 years and am curious how much is there now if any. The ground is constantly changing with erosion and movement it is hard to say. But Yes I will agree the caver presence can be a definate factor. Expessially if the caver knocks of a big rock etc. Just my opinion. I consider my self fortunate not to be in a cave during a "breakdown" but I am always aware of my suroundings.
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Postby hewhocaves » Oct 17, 2005 11:42 am

There was a breakdown inciden in Mammoth a bunch of years ago. More ceiling collapse due to increased airflow than a pile shifting. But is was a significant change. Someone closer to MC cna provide all the details.

"Virgin" breakdown piles are always tricky becasue dozens of cavers havent crossed it and knocked out all the moveable bits. And every now and then you'll see columns that were sitting on breakdown snapped in half because the pile shifted.

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Postby Phil Winkler » Oct 17, 2005 12:13 pm

In the early 80s two young cavers were crushed by a large flake falling in Valhalla pit in Jackson Co. Alabama. They were standing along the side being shielded by this flake while their buddy was climbing. Where they were standing was where me and hundreds of others over the years had stood before. No one (to my knowledge) had ever considered the possiblity of that rock being dislodged.

Since many caves have breakdown piles that had to have happened previously it is logical to assume that breakdown can occur anytime. Didn't that just occur recently in Bowden Cave near Elkins?
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Postby hewhocaves » Oct 17, 2005 12:30 pm

yep. Bowden's been sliced in two because of a breakdown collapse
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Postby Sean Ryan » Oct 17, 2005 3:30 pm

In the case of a lot of active caves - including Bowdens, I think, but I've only been in it the once pre-collapse so I don't remember - the water rushing through them regularly dislodges rocks. That stuff's perfectly understandable.

Valhalla is the oft-sited worst case scenario: a structure that appears completely stable collapsing right when cavers are around. It was the Valhalla case that got me thinking about the slight acoustic, temperature or humidity changes that might trigger something - although Valhallla's an open-air pit, so all those factors are negligable compared to what mother nature throws at the cave in a given year. Was that just monumentally bad luck, or did the cavers' presence trigger that in some way?
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Mammoth cave rockfall

Postby cvr602 » Oct 17, 2005 5:01 pm

I think it was around 10 or 12 years ago, maybe more, but it was the lowest temperature kentucky had seen in a LONG time. The air was so cold in the Rotunda room that the moisture between the rocks in the ceiling froze, and after it got warmer, and thawed, expanding and making around 9 tons of rock fall. This was during the off season, and there were no tourists. It damaged railing and some of the saltpeter remains.

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Postby Grandpa Caver » Oct 17, 2005 6:58 pm

Too many years ago, we were exiting a well known and well visited cave here in Hoosierland. Our group included several first timers. The 25 or 30 (?) foot vertical entrance was lined with 55 gallon drums. We had rigged the ent with a ladder but it was taking some time to get our large group out. I was stationed at the bottom of the ent and a fellow caver had stopped to wait about 75 feet away and halfway up a breakdown slope. Suddenly the earth shook and the ground roared! The newbies screamed, cavers cursed and ladder climbing records were broken by the 4 or 5 of us still in the cave! A very large (maybe 40 X 60 ft) section of wall had suddenly collapsed. The only actual witness to the event was our frind waiting on the breakdown. He jokingly admitted he had been lightly tossing pebbles down the slope but swore he never struck the wall. Fact is, the wall was riddled with gypsum and I've no doubt it simply chose that moment to give in to gravity. That technicality however did not prevent our friend from being forever forbidden to throw. toss or in any way propel a stone while caving!

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Postby Grandpa Caver » Oct 17, 2005 6:59 pm

BTW: None of the newbies ever went caving again.
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