digging horizontal calcite beds

[Bob Smith]

Has anyone had any success digging horizontally bedded calcite beds alternated with partially calcited damp/wet gravel and sand. Have previously tried banging without much success as the layers seem to absorb the shock very readily, the calcite is around 25-30mm thick with thicker beds of gravels between, laying flat out with not much room to swing tools. Solid roof, but would prefer to leave this intact.

 

[shotlighter]

Sounds like one of the few cave situations where a jigger or air chisel might come in. Or possibly an SDS on hammer only? How much room you got & is a source of power, air or lecky available? Obviously you'll still have to scrape the mud/gravel out but at least it should break up the calcite. Good luck!

 

[Bob Smith]

Access isn't really suited to getting a big genny up to the site (heavily wooded, steep, relatively distant from road) although we did drag a cylinder mower up there to use as a winch a while back. The area is fairly public so anything would have to be dragged back again or well hidden. We knackered plenty of SDS drills using them as breakers, but I think a larger tool may be man enough.

 

[AndyF]

Dunno if this will help in your situation, but it worked for us.

Get a small hydraulic car jack (about £10) between ceiling and calcite floor. Jack it up and the calcite will (!) break and can then be lifted with a crowbar

 

[shotlighter]

We're using a 1KVA "B&Q" jenny at the moment (chained to a tree for security), that should be fairly easy to get up there if you can get a mower there!
Another methods springs to mind is a water pump and hose, if the gravel/sand will wash out. We're using this very successfuly to deal with a boulder clay choke at the moment. Of course it's pretty site dependant - last thing you need is to turn it into an underwater dig!

 

[shotlighter]

Dunno if this will help in your situation, but it worked for us.

Get a small hydraulic car jack (about £10) between ceiling and calcite floor. Jack it up and the calcite will (!) break and can then be lifted with a crowbar

Thats not a bad idea! If you're really stuck for room what about one of those hydraulic spreader jaws & pump for body repairs? I've seen them as cheep as £30ish.

 

[Bob Smith]

The jack sounds great, will have to have look. Water is not really an option as I don't think it would be effective in this situation

 

[SamT]

Hi

Dug though quite a lot if this kind of stuff in the past - Vienetta we used to call it, mulitple layeres of thin calcite with pockets and layers of soft mud.

Banging was the solution.  Drilling under and inserting. Yes it does seem to abosrb the shock rather well - but we just kept plodding on.

 

[gus horsley]

I had a similar siuation which was resolved by using a long bar (the length dependant upon the height of passage), hammering it into the mud/sand and then using a small rock as a fulcrum and forcing the calcite layer up.  It worked quite well in the low crawl we were digging but progress in these sort of conditions is always going to be slow..

 

[AndyF]

We're using a 1KVA "B&Q" jenny at the moment (chained to a tree for security), that should be fairly easy to get up there if you can get a mower there!

I got a hard time for suggesting the "B&Q" £99 gennies on the other thread...  :blink:

If you're using one, what are they like....? Are they 4 stroke?

 

[shotlighter]

We're using a 1KVA "B&Q" jenny at the moment (chained to a tree for security), that should be fairly easy to get up there if you can get a mower there!

I got a hard time for suggesting the "B&Q" £99 gennies on the other thread...   :blink:

If you're using one, what are they like....? Are they 4 stroke?

See post I left at end of said thread. Basically grand & yes!

 

[mrodoc]

car jack is what got into Reed's Cave in Devon

 

[underground]

Hi

Dug though quite a lot if this kind of stuff in the past - Vienetta we used to call it, mulitple layeres of thin calcite with pockets and layers of soft mud.

Banging was the solution.  Drilling under and inserting. Yes it does seem to abosrb the shock rather well - but we just kept plodding on.

Yep. Slowly but surely- you just have top put the regular hours in - and it's worth remembering that, as in the situation Sam alludes to, the layers aren't neccesarily continual throughout the dig. You might hit a big pocket of soft sand that goes on for plenty of feet, cos the calcite protected it and it stayed nice and soft and filled the passage in a bit higher.....

 

[Johnny]

The trick, you will remember, was to use a pattern of three small charges spaced in a triangular pattern with about 30cm between them which were let off simultaneously. They were all set around 75cm deep and we got little, if any, throw forward. I suppose we gained about one metre with each go.

 

[graham]

car jack is what got into Reed's Cave in Devon

Wouldn't they lend you a key? 

 

[Johnny]

Another method that was deployed by the late Mr Bentham was to ram a 1m length of plastic waterpipe, packed with the right stuff, under the calcite layer and let that go. Although this creates more of a trench rather than taking out the whole calcite layer.