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Author Black powder blasting any info?
Mr.C

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Joined: 23/03/2008
Location: North Staffordshire

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Black powder blasting any info?
Posted: 07/04/2010 23:35:34
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Morlock's quite correct, the O2 is supplied by the potassium nitrate - nothing to do with the space between grains, otherwise bobbin powder would never have worked!
For example, stem with an almost dry mix of 50/50 sand & clay. Typical pop shot is 16mm hole just under 1/2 full of medium grade blasting powder (1 1/2 oz ish), small bit of paper wadding then rest stemmed in three increasingly firm sections. Hole length typically 600mm, fired with electric squib. This will easily reduce a 3ft cube boulder.
This is an effective technique if used correctly but black powder is very unforgiving.
Poor training, carelessness etc. will if you are lucky kill you.
If you are not, it will maim you or worse still, maim or kill someone else - YOU HAVE BEEN WARNED
Do NOT use this as instructions on how to do it - you MUST have proper training!
Last but not least, in the UK you also need an explosives licence.



--

If things dunner change - the'll stop as the' are.
IP: 91.110.104.122 Edited: 08/04/2010 00:23:59 by Mr.C
Morlock

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Black powder blasting any info?
Posted: 07/04/2010 23:50:46
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Mr.C wrote:

fired with electric squib.


I would think the squib wires, being smaller in cross section than fuse would considerably improve the stemming effectiveness.

IP: 82.27.1.28
Mr.C

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Black powder blasting any info?
Posted: 08/04/2010 00:19:13
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Morlock wrote:

Mr.C wrote:

fired with electric squib.


I would think the squib wires, being smaller in cross section than fuse would considerably improve the stemming effectiveness.


Certainly does in the small holes that are used in mine / cave digs.


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If things dunner change - the'll stop as the' are.
IP: 91.110.104.122
derrickman

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Black powder blasting any info?
Posted: 08/04/2010 08:02:45
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personally I would tend to feel that for the kind of small-scale, controlled splitting of boulders for specimens being suggested, it would be better to use drilling and splitting using plug and feathers, either manual or hydraulic.

That's quite apart from the various issues of training, sourcing, storage and safety already discussed.


as for caving digs I do tend to be rather sceptical, to say the least. Use of explosives in temporary supported headings without compromising or collapsing the whole structure in the process is a skilled business.

IP: 92.3.239.216
Morlock

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Black powder blasting any info?
Posted: 08/04/2010 14:09:52
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derrickman wrote:

as for caving digs I do tend to be rather sceptical, to say the least. Use of explosives in temporary supported headings without compromising or collapsing the whole structure in the process is a skilled business.


Not much experience of mine digs but cave digs tend to be a combination of reducing large boulders so they can be manhandled or sorting out boulder chokes which have well defined walls (somewhere).

IP: 86.31.65.223 Edited: 02/05/2010 12:12:09 by Morlock
Tamarmole

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Location: Tamar Valley

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Black powder blasting any info?
Posted: 08/04/2010 18:45:48
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I'm not sure that this is a healthy discussion to be having, especially in an open forum.

The only way to use explosives underground in an amateur context is properly and as a member of the EUG. Training is a must.

Pratting around with black powder underground is suicidal- its incredibly sensitive stuff.

If something goeas wrong you may be risking the lives of members of your local CRO.

Even if you don't manage to kill yourself you may well be leaving a potential death trap or others either in terms of bad air or loose ground.

If you are not using explosives legitimately and you get caught it will undoubtably f*** up the future situation for legitimate explosives users who have a hard enough time as it is.

The only explosive related fatality in British Caving /Mine exploration was the result of prats using home brewed explosives. (Cote Gill Pot).
IP: 86.171.236.16 Edited: 08/04/2010 18:47:45 by Tamarmole
Phil Ford

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Location: Caernarfon

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Black powder blasting any info?
Posted: 08/04/2010 21:06:52
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The dangers of using any explosives even for experienced shotfirers can be deadly.
I worked with another shotfirer who had a black powder charge in a shothole go off in his face, he was lucky only to have half his face burnt and be left with a lot of blue scars. If it had caught him full in the face it would probobly killed him.
IP: 86.131.29.70
mikebee62

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Black powder blasting any info?
Posted: 08/04/2010 21:17:06
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Thanks for all the info on black powder, I think its going to be feather and wedge for me!!!. Sounds very dangerous even with safety precautions!!

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'Of cause its safe, just dont touch anything !!'
IP: 81.158.166.197
mikebee62

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Black powder blasting any info?
Posted: 08/04/2010 21:28:52
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Found this on the internet, very interesting , but as usual only in the US

http://www.rockremoval.com/index.html


Not sure how practical/safe or legal this would be over here but some interesting alternatives!! and they sell feather and wedges at a good price , not sure how much postage would be!

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'Of cause its safe, just dont touch anything !!'
IP: 81.158.166.197
Strangely Brown

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Black powder blasting any info?
Posted: 08/04/2010 21:48:28
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Graigfawr wrote:

mikebee62 wrote:

Does anyone on here have any experience blasting with gunpowder??


Whilst I've never blasted with blackpowder, I have 24 years experience of black powder ordnance. Lessons learnt: it is easily spilt and incredibly easy to ignite: be very careful!

Seem to recall reading that over-compaction due to over-ramming stemming is potenetially a problem as unlike high explosives which evolve their own oxygen, blackpowder relies on the air trapped between the grains - over ramming it risks there being insufficient oxygen for complete combusion.

Bickford safetly fuse will make the process safer and more certain.

Specify blasting grade powder, not firearm grade powder. Blasting grade has much larger grains; I presume this helps trap the right amount of air despite hammering the stemming into place.


The air spaces are more likely to have any effect due to thermodynamics, the compression from the initial ignition heating the gas will cause the detonation of the rest of the explosive (similar to heating in an ic engine), tamped too tightly the flame has to propogate through the fuel producing a slow burn (like a rocket), I'd guess this is what is blowing the stemming out, with a fast burn the presure would build much quicker spliting the rock before there's a chance to blow the stemming out. With low explosives mechanics like stress concentration will have a much greater effect.

High expolsives are detonated by the shockwave.

Just split your samples with a hammer and chisel, it's safer and can be done at home!

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IP: 86.170.101.145
ditzy

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Black powder blasting any info?
Posted: 08/04/2010 22:14:40
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seen hilti and ramset cartridges / caps used in our dig
v good for boulders but look tricky to get rite

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im the ditzyest ditzy in ditzy land
IP: 86.146.115.5
Graigfawr

Joined: 04/11/2009

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Black powder blasting any info?
Posted: 08/04/2010 22:39:14
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Thanks for correcting my misremembering that O2 comes from KNO3 Blush and for clarifying why over-ramming retatrds the reaction.

There was a very informative recent thread on uk caving forum on use of, and places to buy wedge and feathers - advise checking it out.

Black powder is subject to the same licensing regulations as all other explosives - and you must be licensed for each sort of explosive you acquire and use. Black powder is UN0027 & UN0028. Safety fuse or other regulated forms of detonation must be specifically mentioned on your certificate.

For amateur mine/cave use join the EUG - they can advise on all aspects of explosives acquistion and use. You'll find that cavers never use blackpowder - it is problematic / unviable in damp / wet conditions, and has safety issues that modern explosives do not suffer from. These factors are why commercial use of blackpowder survived for so long in only a few specialist areas such as slate quarrying where low velocity was necessary. You'll also find that cavers can advise on a wide range of methods of controlled breaking of rock that provide alternatives to explosives.
IP: 78.149.22.24
derrickman

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Black powder blasting any info?
Posted: 09/04/2010 08:31:25
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what TamarMole said.

boulder chokes especially, tend to move under their own weight and internal structure. The choke in Dow Cave, now blocked entirely, was a classic example.

Splitting a single component, especially by percussive means, is a completely unpredictable operation which could achieve anything from increasing the pressures holding it together, to collapsing the whole structure.


owaincbrown's post reminded me of a piece of ancient history, I once acted as "Sergeant at arms" for a military re-enactment group ( held the black powder and detonator store at events ) and I learnt quite a few things about black powder at that time, most of which I would rather not have known.

Over-ramming, or insufficient ramming, of black powder fire-arms does indeed produce a range of mishaps, leaving the ramrod in the barrel in the heat of the moment is not a good thing to do Shocked and nor is reloading too quickly without cleaning the barrel properly.

it was a surreal period, being a member of a group of specialist enthusiasts whose interest I didn't particularly share Blink





IP: 92.3.239.216 Edited: 09/04/2010 08:44:38 by derrickman
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