Cryogenic Digging

[Space Kadet]

Hello,  I had this idea about freezing cave mud with liquid nitrogen so it could be broken into chunks and removed easily from the dig.  Also freezing water in a sump or duck into giant icecubes so the sump could be drained. 

I feel it could work.  Has anyone out there tried taking liquid nitrogen into a cave?

 

[bograt]

I suspect protective gear against frostbite would be more hassel to take down than the Nitrogen bottles!!

 

[graham]

Having tried to dig an iced up choke in the Alps in my youth, I suspect that freezing the stuff would make it harder to get out, not easier.

 

[Space Kadet]

A pair of mittens and an apron could easily be rolled up in a digging bag.  I wouldn't suggest this is a main stream technique but could be of some use.

 

[cap n chris]

When the nitrogen boils off in the closed confines of the cave what are you using as breathing apparatus so you don't pass out?

 

[Space Kadet]

Hmm, okay maybe freezing large areas of mud is not feasible but what about freezing rocks with small amounts of liquid oxygen to make them easier to break up.

 

[cap n chris]

No. Nope. No way. You aren't serious. A rock isn't going to be any easier to break just because it's freezing cold.

 

[Alex]

It would if you then took a blow torch to it but by the time you have done that you may had well smashed it with a hammer and chisel.

 

[cap n chris]

Shhhhhh. Shhhhhhhhhhh!

 

[Space Kadet]

Yes it will. All rocks and concrete for that matter contain a massive amount of liquid or pore water.  When frozen this would expand and cause micro fractures in the rock.  You must of seen frost damaged pots outside, freeze thaw action is massively distructive at normal sub-zero temperatures at hundreds of degrees below zero the rock would become as fragile as glass. 

 

[cap n chris]

Thanks for the scientificky bit.

In most digs the only rocks that need breaking up are large - anything small is easily moved. Large rocks being frozen with liquid nitrogen. Are you sure about this?

I'm sorry, but I can't help thinking it's 1st April. I mean welcome to the forum and all that but, really,.. you aren't serious are you?

 

[bograt]

Sorry, I don't intend being underground in confined space with anything that is "hundreds of degrees below freezing".  :thumbsdown: :thumbsdown:

 

[Alex]

Not only that I presume its pressurised so like diving bottles a serious knock and then boom, frozen death.

 

[Space Kadet]

Yes, I'm very serious. It is only a matter of time before the powers that be take away cavers explosive licenses, one mistake is all it will take! Hilti caps may also be banned one day soon leaving cavers with plug and feathers and chiselling rocks.  New techniques must be developed to replace explosives. 

Yes Hilti do make lovely drills but what is the point in a shot hole when you have nothing to fill it with.  Microwaves and sonic devices could be used to break rocks but these would be very expensive and complex to use.  Rocks are broken down naturally by freeze thaw action and excellerating this action using liquid gases seems to be logical, cheap and legal approach to take.  You have to think outside the box.

 

[Oceanrower]

A pair of mittens and an apron could easily be rolled up in a digging bag.  I wouldn't suggest this is a main stream technique but could be of some use.

Your right. Definitely wouldn't work for a main stream.

a small tributary maybe.....

 

[shortscotsman]

Liquid nitogen is always transported in unsealed containers to let the vapour escape. 

If 1 litre of liquid nitrogen vaporises it produces 694 litres of vapour. (at 20C). So a sealed full flask would end up at
694 bar when it warmed up.    Not good. 

 

[martinm]

Yes, I'm very serious. It is only a matter of time before the powers that be take away cavers explosive licenses, one mistake is all it will take! Hilti caps may also be banned one day soon leaving cavers with plug and feathers and chiselling rocks.  New techniques must be developed to replace explosives. 

There are many ways of breaking rocks up already without HE. see for instance:-

http://www.dexpan.com
and:-
http://www.nonex.co.uk/

depends on the individual situation which is most suitable. There's many more too if you know how to use them. Not to be discussed on an open forum perhaps though. Though some like Dexpan are quite legal and safe to use to split rock, (they use it in quarries to cut big chunks of rock out), but it can only be used in large holes drilled downwards cos it's a liquid I believe when mixed, then expands massively...

You just need to know how to use them. They are not explosives, most are propellants (not Dexpan, that just expands) or similar...

Be safe, get training on how to use stuff, be discrete and respect landowners, etc. Sure there'll be loadsa peeps on here for guidance. But HE is most definitely not generally required these days usually... (it just generally just creates more rubble to be removed, lol.)

(Feel free to moderate as felt required mods!

 

[Rob]

Space Kadet. I strongly agree with your viewpoint that new methods need to keep evolving. Likelihood is that nobody here really knows if freezing stuff is the answer, so if you have access to liquid oxygen or nitrogen then i encourage you to safely go and try it and report back...

Maybe not in a cave for the first time, to avoid unnecessary potential consequences.

 

[TheBitterEnd]

?????? 

 

[Bob Smith]

I have had some experience of ground freezing to reduce the ingress of ground water into excavations, both liquid nitrogen direct injection (fast but expensive) and low temperature saline circulation. The refrigeration plant for the latter is quite bulky, but I wonder if it could be adapted for small scale use.  :-\

I'm not sure what direct freezing of rocks with liquid nitrogen would bring to the table, the risk of being overcome by lack of oxygen would, I suspect, for outweigh the benefit of an easier to break rock.

In my experience of trying to break any frozen matrix at low temperature the frozen water simply remelts, briefly, as any percussive shock passes through it and then refreezes. You can get a similiar effect by squeezing two ice cubes together, they weld themselves together.