Author Topic: Bolting  (Read 2250 times)

Offline markpot

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Bolting
« on: April 15, 2021, 04:09:15 pm »
We have been granted kind permission to explore mines on a farmers land. First adit ,we hit a natural pot with a sizable chamber visable at the bottom .what are people toughts on the approach to bolting this initially? we have disscussed the many options from concrete  screws to chemical anchors,but some of us dont feel happy with the concrete screw option.given there is a high chance caver access would be granted in the future, i was interested in peoples opinion of weather to pop in some temporary anchors or bolt it properly from the start?all opinions welcome,including anchor selection/resin.

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Bolting
« on: April 15, 2021, 04:09:15 pm »
Warmbac

Offline owd git

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Re: Bolting
« Reply #1 on: April 15, 2021, 04:48:21 pm »
wouldn't the holes from concrete screws be a starting pilot for a larger drill-bit for bolting? and prove positioning. win win!.
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Offline JohnMCooper

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Re: Bolting
« Reply #2 on: April 15, 2021, 04:56:47 pm »
I've always been wary of using pilot holes with a hammer drill as it puts all the stress on the edge of the tungstem carbide tip. No idea whether it really matters but would welcome feedback.

Offline Benfool

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Re: Bolting
« Reply #3 on: April 15, 2021, 05:07:57 pm »
I'd personally start off with concrete screws for the original exploration (I used 8mm Fischer FBS II recently and they were really good), then swap them for glueins if I wanted it to be more permanent. I did exactly this for a project in Swaledale and it worked really well - I redrilled the 8mm hole with a 16mm hole and used the larger Raumer glueins from Tony.

I've got a load of spare concrete screws if you want some?

B


Offline MarkS

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Re: Bolting
« Reply #4 on: April 15, 2021, 05:22:48 pm »
+1 for concrete screws. Not a long-term option, but by far the best conservation-wise before deciding whether more permanent anchors are warranted.

If any of your group are unhappy with concrete screws, have a read of this and this, and consider on what basis you might be happier with throughbolts or expansion anchors.

Offline sinker

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Re: Bolting
« Reply #5 on: April 15, 2021, 05:40:29 pm »
+1 for concrete screws. Not a long-term option, but by far the best conservation-wise before deciding whether more permanent anchors are warranted.

If any of your group are unhappy with concrete screws, have a read of this and this, and consider on what basis you might be happier with throughbolts or expansion anchors.

For reasons that I don't have time to go into here and now, under NO CIRCUMSTANCES should you use concrete bolts / thunderbolts / anchorbolts, call them what you will.

When I get home later I'll expand on the reasons but PLEASE put that thought out of your head right now.

You need STAINLESS throughbolts or STAINLESS resin P-anchors.

As for "temporary bolting"; no. do it once and do it properly.



Ah, well, now, you see...erm...

Offline Badlad

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Re: Bolting
« Reply #6 on: April 15, 2021, 06:23:23 pm »
I've only used concrete screws a couple of times in caving - lots in construction work.  I have read the testing done by Simon Wilson and discussed their use with other knowledgeable cavers.  I was convinced that these are a really good short term option for rigging especially with the conservation arguments and reuse of holes.  In the fullness of time and when a route is settled on then sure there are better fixings such as resin bonded anchors etc.  I'll be interested to read the reasons for your dislike of them and how that conflicts with other opinions and testing.


Offline pwhole

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Re: Bolting
« Reply #7 on: April 15, 2021, 06:25:56 pm »
If access is almost certain, and the placements are known to be perfect for all the right reasons, go ahead and do the permanent stainless options. As for the temporary options, I've been using Excalibur bolts for ages with no issues, including a test batch left loosely in the wall of a very wet shaft for over a year that showed zero corrosion on removal, but I'll wait for sinker to get home first ;)

Offline Fishes

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Re: Bolting
« Reply #8 on: April 15, 2021, 07:26:04 pm »
Excaliber Screwbolts are my bolt of choice for exploratory work and for moving boulders.

They don't work in all rock types but what bolts do.

Offline ChrisJC

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Re: Bolting
« Reply #9 on: April 15, 2021, 07:43:07 pm »
I am sure the BCRA or BCA did some research on this as I saw the test bolts in Braich Goch. But I don't know where the results are.

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Offline PeteHall

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Re: Bolting
« Reply #10 on: April 15, 2021, 08:29:03 pm »
For temporary rigging, are there no natural options, or failing that a removable stemple, if you are really worried about conservation?

Offline Badlad

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Re: Bolting
« Reply #11 on: April 15, 2021, 09:34:17 pm »
I am sure the BCRA or BCA did some research on this as I saw the test bolts in Braich Goch. But I don't know where the results are.

Chris.

MarkS above has given the links in post 4.  Mark is also the BCA E&T convener. 

Online Pete K

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Re: Bolting
« Reply #12 on: April 15, 2021, 09:46:58 pm »
We have been granted kind permission to explore mines on a farmers land. First adit ,we hit a natural pot with a sizable chamber visable at the bottom .what are people toughts on the approach to bolting this initially? we have disscussed the many options from concrete  screws to chemical anchors,but some of us dont feel happy with the concrete screw option.given there is a high chance caver access would be granted in the future, i was interested in peoples opinion of weather to pop in some temporary anchors or bolt it properly from the start?all opinions welcome,including anchor selection/resin.

I've used good quality Fischer concrete screws in limestone and slate for exploration and bolt climbing and if done well, with suitable backups, they are an excellent anchor when you think you may need to put a permanent solution in place in future but want to check it goes first. Stay a million miles away from Spits, they are a relic of the past.
If you do choose to go down the route of resin anchors, feel free to contact the DCA. I'm happy to chat you through the commonly used trusted combos and DCA could potentially offer some assistance.

Offline ChrisJC

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Re: Bolting
« Reply #13 on: April 15, 2021, 09:53:41 pm »
I am sure the BCRA or BCA did some research on this as I saw the test bolts in Braich Goch. But I don't know where the results are.

Chris.

MarkS above has given the links in post 4.  Mark is also the BCA E&T convener.

This was another test - it was done underground in slate.

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Offline wormster

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Re: Bolting
« Reply #14 on: April 15, 2021, 10:25:53 pm »
This was another test - it was done underground in slate.

Chris.

Was that the one done by Miles M a few years back in Cwmothin?
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Online Pete K

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Re: Bolting
« Reply #15 on: April 16, 2021, 06:41:01 am »
I don't believe they tested concrete screws. This was a body of testing done to approve the BCA BP resin anchor in slate, as previously it was only tested and installed in limestone. IIRC Gethin tested BP, IC and expansion anchors in 3 different slate bodies.
Some details can be seen on his site: https://www.train4underground.co.uk/.

Offline ChrisJC

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Re: Bolting
« Reply #16 on: April 16, 2021, 06:58:53 am »
This was another test - it was done underground in slate.

Chris.

Was that the one done by Miles M a few years back in Cwmothin?

It seems there were a few - Miles was involved, but I was thinking of this one at Braich Goch (Corris) that Pete K linked to:

https://www.train4underground.co.uk/bolts-in-slate-testing-project/corris-test-bed-braich-goch/

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Offline sinker

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Re: Bolting
« Reply #17 on: April 16, 2021, 08:40:14 am »

but I'll wait for sinker to get home first ;)


I still don't have time to fully expand. I'll let the thread run it's course, but again, PLEASE don't use concrete bolts.
They'll be fine for a couple of years then they'll get forgotten about. Next thing some future explorer will come along and rig off them and fall to his death.
With ANY LUCK he would put a spanner on it first and check the tightness. Then when he nipped it up the head would shear off (which is what happens with them) before it was rigged.

The torsional stress in those bolts is unbelievable. If the hole is a few microns too tight, due to a bit of residual dust or slightly worn drill bit, then the torque applied can put so much torsional stress into the bolt that the end of the thread is 1/4 of a revolution behind the head. This is why the heads snap off them. Torsional stress and stretch. look carefully at the shank under the head and the casting where the thread stops and the shank starts. the ALWAYS shear off in either of those two locations.

Final point, although I could go on all day, I have yet to see any of this type of bolt (Hilti / Fischer / Ankabolt etc etc) where the manufacturer actually states that they are suitable for suspending a human being on.

That final point is all you need to know.

As a Temporary Works Designer / Co-ordinator I can sort out all sorts of temporary works designs which use this type of bolt for holding down shutters, hand rails (in a load-share situation), soffits etc but in the last 20 years since their widescale introduction I have yet to see a design which approves them for use in suspending a human being in an access, fall restraint or fall arrest situation.


Ah, well, now, you see...erm...

Offline Down and beyond

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Re: Bolting
« Reply #18 on: April 16, 2021, 10:08:31 am »
As a absolute novice in srt  may some one send me a link to a picture of the bolts some people are saying are bad ? So I can check if I ever see any please  ;D

Offline wormster

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Re: Bolting
« Reply #19 on: April 16, 2021, 10:16:21 am »
It's simple if it has glue round it and it's made of stainless steel it'll probably be ok if it doesn't spin or move. If it's got a hex head on it treat with suspicion, infact treat ALL anchors with suspicion
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Offline Bob Mehew

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Re: Bolting
« Reply #20 on: April 16, 2021, 10:28:38 am »
In the 15 plus years I have been involved with E&T committee, bolting in mines is something E&T has never got to grips with.  (There was Gethin's work & some done in Devon & Cornwall, but the main focus has been on limestone.)  I would list the major areas not yet answered are:

    a) the different rock type and its bedding (or cleavage) patterns,
    b) inbuilt rock stresses induced by blasting, and
    c) corrosion due to water contaminated by minerals. 

The nearest E&T got to considering the topic was a comment which came from Cornwall of using an easily extractable throughbolts and removing them between trips to minimise corrosion.  But that just deals with the heightened corrosion problem.  And no doubt there could be other areas needing consideration.

Offline sinker

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Re: Bolting
« Reply #21 on: April 16, 2021, 10:35:21 am »
As a absolute novice in srt  may some one send me a link to a picture of the bolts some people are saying are bad ? So I can check if I ever see any please  ;D

There are hundreds of different types / sizes / materials etc but typically they look like this:

https://www.screwfix.com/p/easyfix-bright-zinc-plated-carbon-steel-concrete-bolts-m10-x-100mm-10-pack/5800P?tc=CA8&ds_kid=92700048793290424&ds_rl=1249413&gclid=EAIaIQobChMIzOLTubqC8AIVi9d3Ch19zAJpEAQYBCABEgKW_vD_BwE&gclsrc=aw.ds

!!! AVOID !!!



Ah, well, now, you see...erm...

Offline Fishes

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Re: Bolting
« Reply #22 on: April 16, 2021, 10:36:29 am »
I use concrete screws are a temporary solution. If it doesn't go then I take them out and they can be used again. If it goes then I take them out and put in fixed stainless steel anchors. That's my personal choice as they can take a lot more loading than my body and I never hang on only one bolt of any type. You won't shear them off if you use the appropriate length spanner (important for many bolt types).

I choose to use then because they cause minimal damage and don't leave scrap metal littering the place.

Spits are  also useful for longer term use in certain limited conditions. These days I would only use then in places where I wouldn't want to take my drill or a Rocpec, both of which stop working if you fill them with wet gritty crap. In my experience they are generally good for 20 years or so if people don't fuck up the treads by constantly removing and replacing the anchor plates. They can be removed but its a bit of a faff.





Offline mikem

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Re: Bolting
« Reply #23 on: April 16, 2021, 10:39:13 am »
I'm hoping some people actually mean expansion / through bolts, when they are saying concrete screws (which as sinker shows, are a different thing altogether).

If you do use concrete screws then they should be removed immediately after use, so they aren't left for others in future.

Offline Down and beyond

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Re: Bolting
« Reply #24 on: April 16, 2021, 10:48:38 am »
As a absolute novice in srt  may some one send me a link to a picture of the bolts some people are saying are bad ? So I can check if I ever see any please  ;D

There are hundreds of different types / sizes / materials etc but typically they look like this:

https://www.screwfix.com/p/easyfix-bright-zinc-plated-carbon-steel-concrete-bolts-m10-x-100mm-10-pack/5800P?tc=CA8&ds_kid=92700048793290424&ds_rl=1249413&gclid=EAIaIQobChMIzOLTubqC8AIVi9d3Ch19zAJpEAQYBCABEgKW_vD_BwE&gclsrc=aw.ds

!!! AVOID !!!

We use to use them in manholes a lot and I completely agree I have put in thousands and snapped many with socket sets nut runner guns  ! I would not  personally dangle of them  we stopped using them in manholes and switched over to the steel wall plug design with a bolt also used glass tubs of rezin in the hole when you hammer the bolt in it smashes it making it mix , with the design you have to use the air pump tool to clear out any dust though .

 

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