Cave collapse

[FW]

I agree. What amazes me is a new sink hole will form in Florida ...

Like this one? http://abcnews.go.com/WNT/video/mass...veway-26821992

[h2ojoe]

Wasn't there a recent collapse at Convict? About 500' in?

[Yannis]

The accident happened after the half hitch movement,but everything had been covered by a very fine clay,which was easy to stir up. The line wasn't broken,but buried in the debris. There was a white line that was installed,but a contribuatory factor for the accident was supposedly there was a line arrow facing the wrong way that lead them back into the cave. Their computer download verified this. Sometime later the Bruics sold the site,and it became state property but had a contractors handling the place would vacillate between opening it to diving or not. This wasn't due to the accident,but due to ineptness. Once it became a state park,diving has been allowed. Can shifting at the half-hitch happen again-yes,but nobody knows what was the cause.

Thanks Kelly. Sounds like those divers found themselves in an incredibly difficult situation.

[Greenwood_60]

According to the owners, convict is currently unstable. There is a sink hole developing over the collapse. It's still open to diving up to that point.

[w ripley]

Don't know if you caught it but 60 Minutes did it's lead-story this weekend on the effects in California of wholesale pumping out its underground aquifer. In one place the aquifer's water level was measured to have fallen 200 feet. No surface sinks or collapses were reported, like in FL, but they showed one place where the ground elevation had already fallen several feet. Can't imagine what the long-term impact is going to be.

On a side note, wholesale removal of underground "drinking" water for other purposes + our increasing contamination of that water by fracking, etc., will most likely catch up with us. Wonder how it may impact cave diving?

[WEPIV]

I saw part of that 60 Minutes story.
How about only having people live in an area that can actually sustain it? Don't know exactly how that could be accomplished but one way or another it will likely lead to it one of these days.

[Brent]

Don't know if you caught it but 60 Minutes did it's lead-story this weekend on the effects in California of wholesale pumping out its underground aquifer. In one place the aquifer's water level was measured to have fallen 200 feet. No surface sinks or collapses were reported, like in FL, but they showed one place where the ground elevation had already fallen several feet. Can't imagine what the long-term impact is going to be.

On a side note, wholesale removal of underground "drinking" water for other purposes + our increasing contamination of that water by fracking, etc., will most likely catch up with us. Wonder how it may impact cave diving?

Here's a story that you "old" cave divers might remember. In the late 92 time frame there was a fatality at Alachua Sink. At that time of the year, the vis was zero down to almost the lower conduit and so the search was done mostly by "feel" This went on for three days and then somebody thought it might help if the sink was pumped out in order to lower the water levels. The pumping started and six or so hours later the eastbound lane of Hwy 441 directly across from Sonny's collapsed as did a small section of the parking lot of what is now the Comfort Inn. These weren't huge sinkholes by any stretch but "any" size sinkhole in the highway is not a good thing! I guess somebody got a map out and realized that the collapse was over an area of the cave and needless to say that ended the pumping. If you go to the Comfort Inn today, it will be obvious where they filled in the hole. On another note, Alachua Sink filled back up to it's normal level in just a short period of time after the pumping stopped. On this day, nature won!

[FW]

Here's a story that you "old" cave divers might remember. In the late 92 time frame there was a fatality at Alachua Sink. At that time of the year, the vis was zero down to almost the lower conduit and so the search was done mostly by "feel" This went on for three days and then somebody thought it might help if the sink was pumped out in order to lower the water levels. The pumping started and six or so hours later the eastbound lane of Hwy 441 directly across from Sonny's collapsed as did a small section of the parking lot of what is now the Comfort Inn. These weren't huge sinkholes by any stretch but "any" size sinkhole in the highway is not a good thing! I guess somebody got a map out and realized that the collapse was over an area of the cave and needless to say that ended the pumping. If you go to the Comfort Inn today, it will be obvious where they filled in the hole. On another note, Alachua Sink filled back up to it's normal level in just a short period of time after the pumping stopped. On this day, nature won!

That is also the reason Alachua Sink is a guided dive to this day.

[shellmoundal]

I would suggest that be a topic for a speaker at the next NSS/CDS Workshop in Florida. I always get good information at the NSS Workshop. I must say it does relate to be a safer diver compared to the NACD Conference.
What about it Forrest? Great topic and it we need an education as to what to look for when cave diving. It was never discussed in my Full Cave Training.

[Kelly Jessop]

That is also the reason Alachua Sink is a guided dive to this day.

....and one of the reasons why guides have concern when the basin and line to the upstream/downstream junction is zero viz. Was a CDF thread recently on why this person couldn't get anyone to guide him. You get off the line in zero viz in the size of the conduit you probably won't find your way to the line,or end up where that victim ended up,which is a worse than Thunderhole incident (remember?)