Sciencemadness Discussion Board

Need advice from experienced pyro

a11051605 - 12-12-2018 at 19:41

Ill start this off by saying I am an amature chemist but I do have a healthy respect for chemicals and exactly following directions for preparation and their use. I was looking to get some input from someone with some knowledge and experience as to a proper way to set off a ANFO charge in a hard rock vein for sampling. At this point this is what I am currently thinking and would like some inputs.

Looking to do a small charge and with ANFO being a tertiary explosive I understand the need of a booster.

Primaries considered: MEKP (mixed in sawdust onsite), MEKP/AP, or MEKP/AN

Booster considered: AN/AL w/flash powder.

Main: ANFO or ANFO/AL or ANNM

Bore hole: 2ft deep by 1inch.

Method: Separate/individual (chemical) paper encased charges packed in lightly with wooden rod. And set of via electric charge in the primary.

Reasons these are being considered is ease of making, cost, and stable enough. Although the MEKP does kind of make me nervous, but from what iv seen its stable enough as a liquid for transport.

Im thinking at this point of a 1g primary setting off a 2g booster to a 4g main should fracture the rock enough to shatter it but not blow it to kingdom come.

Would really like some helpful input on this so it could be done right and most of all safe, also understand there are better chemicals out there like lead azide as a primary but those chemicals are not readily available and the preparation sounds pretty dangerous. Open to ideas on chemicals/mixes just keep in mind the "amature" at the start of this post.

[Edited on 13-12-2018 by a11051605]

[Edited on 13-12-2018 by a11051605]

Tdep - 12-12-2018 at 19:48

1g primary... 4g main?
Flash powder??
MEKP?

I understand that it is hard to get advice when it comes to explosives, seeing as no-one really wants to teach you this stuff. But still, you can't use a jackhammer to break the rock? :)

a11051605 - 12-12-2018 at 21:38

Ya that's the trouble is getting some one to teach or even talk about it, which is kinda sad thats the point our world has gotten to. Any way, yes jack hammer can get rock to break, if you want to some how haul a generator up to location, run power cords, and spend the day working it. Not trying to be a smart ass btw as it would be a valid option if this was say my back yard. Unfortunately explosive is most efficient way as far as time, effort, and cost.

Also on a side note I'm also looking into ETN as a primary.

OneEyedPyro - 12-12-2018 at 22:56

Peroxides of any kind aren't a good idea, and in such small amounts neither is ANFO.
I don't know your level of knowledge or respect of explosives in general and I certainly don't want anyone getting hurt or killed for lack of knowledge or respect.

It's not a matter to take lightly. Missing fingers, severe hearing loss, permanent blindness and death are all a possibility, even in the fairly small amounts you're talking about.
With one slip or poorly thought out action you can instantly find your life ended or changed forever over something that doesn't matter even remotely in the grand scheme of things.

My best advice is to find another way. A sledgehammer and chisel will do the work of 5g of explosives in much less time than the preparation/setting up of an explosive charge.

If you insist on using explosives I'd recommend steering clear of peroxides and investing a bit of time in finding safer alternatives (Azides are not any better for amatuer use).
I'm happy to provide info on how to safely accomplish your task but the safe manufacture/usage of explosives is a very complex thing, and without knowing your exact plan I can't even begin to help you.

hissingnoise - 13-12-2018 at 03:27

Quote:
Also on a side note I'm also looking into ETN as a primary.

Though ETN isn't a primary, it will detonate from flame under strong confinement and its power is comparable to that of NGl...

A column of 4-6 inches ETN within your rock, with BP pressed on top for strong ignition and tightly tamped with dry soil or sand will likely split the hardest rock.

Just don't rush into it ─ some research is advised...

RogueRose - 13-12-2018 at 04:51

Would you be able to make the diameter larger and use something like BP instead? I would bet that the extra amount of time for making the primary, booster, etc would be longer than making the hole bigger and using BP. It was used very successfully to blast through many mountain ranges (Rockies, Andes, Alps, Urals, etc) and I would suspect it would be much safer.

Also, what about making something like nitrocellulose or even NG and then using sawdust and or clay to absorb it. I seem to recall that being an effective method to safely handle it.

I still think BP might be a reasonable alternative and the easiest to make and work with.

a11051605 - 13-12-2018 at 08:37

Actually I have thought about alot about BP due to its historic use and reasonable saftey curve. Was actually thinking of doing some control tests on it by recording time, cost, material used and result in a vein. If BP works I would use it, really only a matter of what shatters the rock with the least overhead and least difficulty. Again sense I am going for shattering rock and not big exciting explosion I think my options are flexable.

Also for people's fyi, locations are remote and involve rough roads and trails so any product needs to take small bumps from travel. Although I think padded case can help with this. Also why I was looking at MEKP in liquid form I have heard it is stable. Only problem I can see with BP is a static discharge but I think that hazard is pretty remote.

[Edited on 13-12-2018 by a11051605]

a11051605 - 13-12-2018 at 08:43

Also would add reason I am looking at other HE other than BP to begin with is the amount carried to do a given amount of work. If it's possible I think a given small compact charge of HE vs large bag of BP would be preferable.

Hard part is figuring out a detonater material sense by there nature most are more unstable, so im open to ideas.

At this point I'm leaning toward ETN as booster over AN/AL w/flash, sense ETN sounds safer then dealing with flash.

[Edited on 13-12-2018 by a11051605]

[Edited on 13-12-2018 by a11051605]

[Edited on 13-12-2018 by a11051605]

a11051605 - 13-12-2018 at 09:16

Also to ward off any more hammer comments I'll provide some more background info. Sample size I'm looking to take is 1/4 to 1/2 ton of rock, we arnt taking a few gram sample or else I would obviously use a hammer. Also quartz and granite rock body's are very resistent to compressive force, i.e. hammer, but are very weak to shock, i.e. HE.

Tsjerk - 13-12-2018 at 09:54

7 grams of explosive is going to scratch the rock, maybe. You need a bit more. I have no idea how much and I'm not going to guess. But make the 7 g charge as a small practice charge.

Go for ANNM, you don't need a booster, but without a primary it is safe. You could set it on fire and drop it down from a flat and nothing would happen.

Now the primary... Those are tricky, ANNM is sensitive for a small detonator so you only need a small one. But a small one will still blow your fingers off. What I used to do was making a bit of PETN (10 grams last a long time), and put it in a drinking straw, like half a cm or so.

Until here things are quite safe, now comes the primary. I used dextrinated lead azide. It sort of dries in grains and as long as you are gentle with it and avoid static electricity it is likely fine. You only need one 30 mg-ish grain to set of PETN. Wear goggles and ear protection and never hold the detonator directly.

Think long and hard before you operate, and practice with sugar or so to mimic the explosives. Practice until you are able to put together a detonator without touching it directly. Half a centimeter (half a gram to a gram of PETN) is not too bad when it explodes, as long as you wear protection and you don't touch it, and it doesn't get the chance to propel metal or thick plastic.

I made a lot of mistakes by going in without experience with real explosives, but I survived. Please don't do the same, practice with fakes, then with BP (I will explain), and only then with a real charge.

For example, I used to use the fuse from fireworks, from what we call "roman candles", 30 cm long and burns for about 30 seconds. My detonator was a coke bottle cap filled with TATP, the side facing the fuse was normal plastic band. Someone told me to use a drinking straw to protect the fuse, but forgot to mention to take it away before lighting. I put it straight up and probably a drop of burning plastic fell down in the detonator setting a 200 g ANNM charge of after only four or five seconds. Could have been a lot worse, now I was only left "shocked". With BP it would have been less bad.

After that I started filling drinking straws with KNO3/sugar and lay them horizontally. Works pretty well, no sparking and burns for a minute orso. Is your drill hole vertical or horizontal? If it is vertical consider re-drilling or electrical means to set it off.

Don't look at detonations that are covered with something, whatever it is. Make sure you are behind something, also with the 7 gram charge, you never know. I never used anything different than plastic bags and straws. Metal or thick plastic will form deadly projectiles.

With electrical means to set of the detonator always connect everything to the detonator before you put it in the main charge. And with every maneuver, be aware there is a chance the detonator goes.

Putting the detonator in the charge is the always the very very very last you do.


Edit: There is a story about someone having a bad accident while making ETN, read it. I forgot his name but someone hear probably can give you a link. I wouldn't dare to make explosives anymore, I didn't do it for at least 10 years. The consequences are just too bad in case it goes bad.

[Edited on 13-12-2018 by Tsjerk]

nitro-genes - 13-12-2018 at 11:44

No experience with rock blasting whatsoever, though some things that seem to be worth looking into:

If the explosives are used underground, use oxygen balanced or slightly over-fueled explosives and use good ventilation. Ammonium nitrate (AN) based mixtures with too little fuel leave nitrogen oxides for example. Like you mention yourself, if you have aluminium powder available, a mix of ammonium nitrate (totally dry and finely powdered), fuel oil and about 2-3% aluminium powder may be most cost effective as a booster (or simply ammonal). Not sure how dangerous the aluminium oxide smoke after the detonation would be, so maybe something to look into. If you work in a very humid environment, remember that ammonium nitrate based mixtures are very hygroscopic and under high humidity can rapidly become desensitized.

Flashpowder can detonate ammonium nitrate/aluminium mixtures, though no idea how reliable this is. It seems far preferable to have an absolutely 100% reliable firring train, than to have a more simple, though less reliable system. Why even bother with making your own detonators/boosters yourself?! if possible I would definitely use commercial detonators, safety fuse and boosters. Dealing with a misfire seems way more work and hazardous. In any case...large amounts of flashpowder are probably more dangerous to work with than really small amounts of a primary explosive as these are sensitive to friction and static as well, so flashpowder doesn't seem very advantageous.

Though if you're really set on using your own detonators,boosters etc...I'd think regarding the safety of loading the detonator, DDNP might be one of the best primaries available. DDNP is one of the least friction and static sensitive primaries available. It is pretty impact sensitive, though I'd intuitively would say friction sensitivity is most dangerous during detonator loading. (maybe other members have other ideas about this) Anyway, once picramic acid is obtained, DDNP is very easy to make. DDNP is a stable primary, is not very demanding regarding pressing conditions and has very good flame sensitivity. Used in a well reinforced compound cap (even without any base charge), 1 gram will probably detonate most things a #8 blasting cap would do.

https://www.hsa.ie/eng/Publications_and_Forms/Publications/M...

[Edited on 13-12-2018 by nitro-genes]

a11051605 - 13-12-2018 at 13:59

I'll look ino DDNP.
Iv read quite abit about ETN and people have done some pretty stupid things in the synth and haven't reported any issues other then low yeilds, which sounds promising sense it appears to to be some what hard to get a runaway reaction.

One thing that would be nice about flash as a primary is that I could keep it binary and mix onsite, same as the MEKP idea and saw dust.

Means of firing will be electric switch saftey away, haven't decided if I will use electric match or bridge resistor. Any way should be away from boom.

Bore holes maybe horizontal or vertical, just depends on location.

When breaking rock you use smaller charges in an array to do controlled blast, not just one big blast.
Big blasts tend to throw rock airborne which is bad, you want the rock to stay put for ease of recovery and flying rocks are bad for your health.

Also of note is that ETN is oxygen rich so would probably help get more energy from ANFO? Just a thought.

[Edited on 13-12-2018 by a11051605]

Tsjerk - 13-12-2018 at 14:09

Quote:
Quote: Originally posted by a11051605  

Iv read quite abit about ETN and people have done some pretty stupid things in the synth and haven't reported any issues other then low yeilds, which sounds promising sense it appears to to be some what hard to get a runaway reaction. .

You haven't read about the guy losing both hands I was trying to warn you about (the ETN story)l
Quote: Originally posted by a11051605  

One thing that would be nice about flash as a primary is that I could keep it binary and mix onsite, same as the MEKP idea and saw dust.

Don't use peroxides. definitely not mixed with unknown crap. Pure compound are nice because they are pure. I wouldn't touch MEKP/saw dust with a ten meter pool.
Quote: Originally posted by a11051605  

Means of firing will be electric switch saftey away, haven't decided if I will use electric match or bridge resistor. Any way should be away from boom.


Don't forget to test. Did you ever test? If so, what did you test?





[Edited on 13-12-2018 by Tsjerk]

a11051605 - 13-12-2018 at 14:25

Absolutely will be testing, just at this point trying to figure out what to synth and test lol.

You are correct as far as story of guy getting maimed, but I will say that is only one iv read about so far, and I do appreciate the heads up.

As far as MEKP and saw dust, lots of liqued HE's have used paper, saw dust, or diatomaceous earth as a soak medium to make them primed for det. Also many references to guys using MEKP with a soak medium for blasting. Note that I'm not married to the idea of MEKP I'm just pointing out.

Thank you for all your replies btw. Lots of good ideas and good inputs let keep it going.

RogueRose - 13-12-2018 at 15:35

I think it would help if we knew what kind of rock you are drilling and blasting or at least how hard it is, size, etc. How long did it take you to drill the hole if you have already? What did you use to do it?

I don't think you need to worry so much about BP when it comes to travel and such. I doubt it will be more than a lb to fill that hole you mentioned and that is sold in gun shops in plastic containers. IDK if that is the type that is usable in this situation, I'm not talking about smokeless rifle/pistol powder, I'm talking about real black powder for muskets. It might be the easiest and cheapest option when you look at the over-all picture.

Another idea with the BP is to drill the hole, put in a fuse/blasting cap, wadding (cloth of some type) and then a plug. I would guess that you would get better results if you really sealed the hole with something like a quick drying epoxy around the plug (or even slow drying/6-24 hr if u have time) to make sure as much energy is transferred into the rock as possible.

Also, when you say "shatter" the rock, what do you mean and why? Do you need it in gravel size pieces for some reason? Or would 20-100lb chunks be small enough to move out of the way.

What is the plan with this rock and why blast it. You will get a lot better answers to your question (and alternatives) if you tell us. If it is for gold or mercury ore or something, don't worry, no one is going to come steal your find.

a11051605 - 13-12-2018 at 17:03

Rock is for metalic ores. That are mostly quartz granite. On a hardness scale I believe quartz is an 8.
When I say shatter I mean break into smaller parts less then say 100lbs. Looking to break then process the rock in bulk sampling to determine value content of rock. Need to do a large sample and get deeper then the weathered surface face of the rock.
Was going to experiment with plugging the hole to incease pressure probably just using some slightly damp/compressed surface dirt.
The BP sold in stores is not real BP, they are a BP substatute that is more stable and most claim less powerful then real BP and go for much more money. If I was to go BP route I would be making my own.

Assuming rock contains values will move into small scale underground mining using small controlled blasts to prove the vein.

RogueRose - 13-12-2018 at 20:39

Quote: Originally posted by a11051605  
Rock is for metalic ores. That are mostly quartz granite. On a hardness scale I believe quartz is an 8.
When I say shatter I mean break into smaller parts less then say 100lbs. Looking to break then process the rock in bulk sampling to determine value content of rock. Need to do a large sample and get deeper then the weathered surface face of the rock.
Was going to experiment with plugging the hole to incease pressure probably just using some slightly damp/compressed surface dirt.
The BP sold in stores is not real BP, they are a BP substatute that is more stable and most claim less powerful then real BP and go for much more money. If I was to go BP route I would be making my own.

Assuming rock contains values will move into small scale underground mining using small controlled blasts to prove the vein.


Well if that is the case then I think BP would be a good choice. I'd be very interested to see the difference between a blast where you use tamped dirt vs where you use something like a metal rod/bolt epoxied in place. Speaking of bolts, if you can drill a nice round hole then you might be able to use a bolt and screw it in. Use a wrench with a long extended arm/lever (like a pipe of some sort). Drill a hole through the bolt to feed the fuse through the bolt.


If you needed it in more of a gravel or small chunks like a couple lbs, then I think a HE would be more effective but for breaking rock free to get to the material below, I think BP will be a good choice b/c it gives a slow powerful explosion not like the much faster shock wave of the HE.

It would be interesting to see how the different EM's work! It sounds like a fun project!

a11051605 - 13-12-2018 at 21:15

Ya I'm looking forward to it. At the mines iv worked at they use ANFO cause for a HE it's slow and if you watch them do an explosion the ground just kinda heaves up alittle then falls back down but all the rock is nice and broken up now. I will be posting results of diffrent tests later on with results of diffrent charges. Luckly iv managed to rope a pyrotech and a master blaster into my little adventure so that will be interesting. Pyrotech was pretty interested in ETN as he had never heard of it b4.

I'm sure BP with an epoxy bolt in place would be interesting as all that energy has to go some where.



[Edited on 14-12-2018 by a11051605]

Tdep - 13-12-2018 at 21:32

Its good to see this thread have healthy discussion, and for OP to take things slowly. Not to de-rail meaningful discussion but:
Quote: Originally posted by a11051605  

Booster considered: AN/AL w/flash powder.

Is this a thing people do? Where has this idea come from, it seems very strange. I feel flash powder has no place in an explosive train, but is a thing that amateurs have been known to do??

[Edited on 14-12-2018 by Tdep]

markx - 14-12-2018 at 00:36

Quote: Originally posted by a11051605  
Luckly iv managed to rope a pyrotech and a master blaster into my little adventure so that will be interesting. Pyrotech was pretty interested in ETN as he had never heard of it b4.


[Edited on 14-12-2018 by a11051605]


In that case you should be able to source and use a reliable commerical initiation device/setup, right? That would take 99% of the danger factor off the rock blasting operation.
It is the primary initiating part of the explosive train that hides the most dangers and causes of failure, especially in an amateur setting. In light of that I would steer off from any improvised solutions for that part (especially what concerns peroxides).
Should one still out of scientific curiosity choose to go all the way from scratch, then for reliability sake I would also not suggest to use combinations that rely upon DDT (deflagration to detonation transistion) effect.....from practical perspective these solutions tend to be very demanding in terms of preparation procedure and still prone to failure. And the result is that one has to deal with a failed blasting charge...a very dangerous and unpleasant activity.

Perhaps the best bet would be the BP route, it is relatively safe simple and functional. With no HE related issues involved.

Herr Haber - 14-12-2018 at 04:37

Great to see that you have thought about this a lot.

I only see good advice in the comments above. Your idea of tamping the charge with epoxy is excellent. Water tamping also works quite well.

A couple of things come to mind:
- I've seen people break limestone with a drill, a .22 long, a metal rod and gloves.
- BP is very cost effective
- Tried initiating ETN with thermite: no joy.
- You have considered MEKP (bad idea)
- You have considered ETN (great but needs primary)
- I am not sure the diameter of your hole is enough for AN based composition.

But...
If you considered MEKP you shouldnt be afraid of nitroglycerine. If you have considered ETN you have the precursors for nitroglycerine and nitrocellulose.
You can make your own gelignite, buy commercial firecrackers and forget about the primary / detonator dilemna.

You know your rock, obviously have made some research and sound safer than many.
Let us know how it goes ;)

a11051605 - 14-12-2018 at 06:19

As I understand it and please correct me if I am wrong but isn't synthesis of NG very risky? From what little I have reaserched about NG I have heard a 2 degree change in temp can trigger detonation? Haven't reaserched NG much cause of its bad rep.

As to the AN/AL w/flash ya it's a thing, makes the AN/AL more sensative in that when grouped as a charge the flash helps kick things off. Not really considering it much now.

With the other pro's involved I do now have access to better blasting gear/tools but still interested in making own charge for scientific and self reliance. Will be nice to have experianced supervision though.

As every one has pointed out the biggest hang up is the primary.
Like the good ideas and discussion.

a11051605 - 14-12-2018 at 07:11

Hmm been reading about NG and kinda confusing cause so much conflicting info out there. Some claim it's super hazardous and will blow up with one wrong look, and others claim to have synth'ed it and as long as you keep your temps in check during synth and treat product with respect that it is actually harder to det then alot of the peroxide based explosives. Any thoughts or experiance any one?

RogueRose - 14-12-2018 at 09:14

As a side benefit I would think that if you use BP you could get away with cannon fuse or even an E-match type thing (nichrome or a bridge wire). If you are worried about initiating he charge you could add some of that flash powder you discussed in a small charge of maybe 1/4 - 1/2 gram (been a LONG time since I've seen FP so IDK the volume anymore...). I think normal fuse should be fine for either though.

Tsjerk - 14-12-2018 at 10:14

Quote: Originally posted by RogueRose  
As a side benefit I would think that if you use BP you could get away with cannon fuse or even an E-match type thing (nichrome or a bridge wire). If you are worried about initiating he charge you could add some of that flash powder you discussed in a small charge of maybe 1/4 - 1/2 gram (been a LONG time since I've seen FP so IDK the volume anymore...). I think normal fuse should be fine for either though.


Blackpowder will ignite with any source of heat without problems. No need for flash powder.

markx - 14-12-2018 at 10:48

Quote: Originally posted by a11051605  
Hmm been reading about NG and kinda confusing cause so much conflicting info out there. Some claim it's super hazardous and will blow up with one wrong look, and others claim to have synth'ed it and as long as you keep your temps in check during synth and treat product with respect that it is actually harder to det then alot of the peroxide based explosives. Any thoughts or experiance any one?


Liquid nitroesters are uncomfortable to work with during synthesis and purification. They tend to bind water and acids and need tenacious netralisation and purification for stability.... may become absorbed into surfaces when spilled....absorb through skin and affect the vascular system (dilation of blood vessels results). Even when mixed with porous material the esters still tend to creep out and become absorbed into surroundings contaminating them.
The sensitivity is not too terrible (e.g. EGDN) , it takes a premeditated attempt to cause a detonation. An occasional light touch or tumble usually go unnoticed, but they are very far from being safe to handle. There are some things to avoid during synthesis though....like glass to glass surface contact. Swirling a glass thermometer around in the reactor, rubbing against the sides or bottom of the flask is a no no. Researchers have been maimed and some have met their end at attempts to synthesize liquid nitroesters....so that should really sum it up.
For general practical purposes there is little to be gained from the liquid esters compared to solid alternatives.

Well....if you really have the intent to study the realm of high energetics in practice, then I would suggest to go slow, in stages and small scale. Do not rush to breaking rocks with an improvised solution without thorough previous preparation or research.

Herr Haber - 14-12-2018 at 12:57

Great, Markx avoided me a long post :)
About purification of nitroesters: the stage is not optional of course but you are planning for immediate use so it may not be as thorough. There's no good reason to store NG otherwise.

You should get a few books from SM Library. All 4 of Urbanski are great reference books. There's been a lot of names and acronyms used in these 2 pages and you'll find them all there. These books are as much about chemistry as they are about history and based on what you say you might fall into them.

That said, based on the conditions you described (access, rock, bore size etc) I'd keep a simple backpacking trip as simple as possible and go for black powder, fuse and a bit of mud picked up on the way or made on site. Peace of mind and all that...
No stress because you dont have to prepare your EM yourself, purify it, package it, prime it, chose ignition type and all that. Maybe you dont need all that trouble. Aaaand of course you can buy black powder legally and you can expect how it will behave. Safety fuse or bickford fuse should be simple to find and better than visco fuse and that's it.
In a 1 inch diameter hole you can put a lot of black powder and apparently you have someone who knows how to drill. If you take some time thinking on how to best make your hole you'll definitely break something. Your objective being the ore after I suppose you'll have plenty of steel with you to process what you break.
A friend says something that translates as "there's no hard rock, only soft arms" :)

[Edited on 14-12-2018 by Herr Haber]

TGSpecialist1 - 14-12-2018 at 20:14

Personally, I'd use 300-400 g of flash powder, mix on site in batches, just pour into the borehole, place fuse/electric cap, plug tightly with a rag, pour about a foot of sand over it, and light it.
No tamping!

Tsjerk - 15-12-2018 at 04:19

Quote: Originally posted by TGSpecialist1  
Personally, I'd use 300-400 g of flash powder, mix on site in batches, just pour into the borehole, place fuse/electric cap, plug tightly with a rag, pour about a foot of sand over it, and light it.
No tamping!


Worst advice ever. Just pour it in? And then put a fuse in it? You want to mix at home, where you are comfortably sitting or standing, put it in a container, like a carton tube or so, and add the fuse. Now you make sure the outside of the container is clean of FP and you are good to go.

If you do what you recommend the fuse will ignite the FP left everywhere, immediately setting of the main charge and blow you to smithereens.

Edit; always make sure you are comfortably standing or sitting when doing something that requires concentration. I always see students who try to for example do microscopy while hanging over their fellow student in an angle no one would like for more than five seconds and then try to find something hard to find. Within ten seconds they start complaining it isn't there... When you study for an exam you also don't go do that sitting on your knees on some rocks. Or balancing because the terrain is not flat.

The first thing I did when a student asked to find something for them through a microscope was to confiscate their chair. I'm not going to hover in mid air doing something that is difficult.

Just mix your FP at home, not in some potentially windy, wet and or dirty field you have never been before.

[Edited on 15-12-2018 by Tsjerk]

MineMan - 15-12-2018 at 13:38

Ok. Fear not. MineMan is here! And I understand your business!

First, I must ask a few questions, then I will give you perfect advice...

1/2 ton sample of rock!? Are you going to do processing test?? Because for assays a pound is enough!

Second, how large is your vien? We want to minimize dilution...

What minerals are we after? Quartz so I assume native gold....

For underground mining a powder factor on the order of 2-4lbs will suffice. But that is with a well designed blast, this is a single hole, the problem is we only have one free face to break to... which means more powder!

Are you Drilling this hole with a hand steel??

Honestly, your not going to get a half ton sample with 1 inch hole 2 feet deep...but maybe 100-200lbs.

What is the orientation of your vien, will the hole be vertical or horizontal because if we can get that hole deeper stemming will help!

Can you give us a brief rockmass discription? Joint sets, weathering, alteration? If it’s highly mineralized it should blast rather easy.

Last question, do you need a mining partner :D??

Ok. Here is what you want to do, forget primaries, you DONT NEED them, all you need is your standard 70/30 flashpowder and ANAL... sure you can add a few percent diesel, even the standard 6 percent will work. ANFO CAN be detonated by FLash in a hard rock environment.

Mix up 5-10 grams of flash, (the more cofienment the better) and fill your hole with 5% Al, 92%AN, and 3% ethylene glycol or diesel... yes crush the AN prills.

Remember, when a single borehole is blasted it makes a crater in the shape of a carrot... therefore there will be dilution because at the top of the hole I it will blow out more than the vien while the bottom it will just blow out a sliver.

PM me if you want, this stuff is like candy...

If you can tell me what type of test you plan to run on the ore I can help you choose the best “blast”

[Edited on 15-12-2018 by MineMan]

RogueRose - 15-12-2018 at 18:01

IDK how much adding a sealant helps contain the blast, I would think it would help at the bottom/deepest part of the hole. Maybe something like an 1/2" of sand could be added and then melted paraffin could be added for a few inches above it (in the hole). From what I remember paraffin doesn't compress (or at least not much) so maybe that can act like water in some way w/o worrying about adding water to a hole that could destroy the charge.

a11051605 - 15-12-2018 at 21:06

Nice reply MineMan, can tell by your questions and reply that we both have the miner mindset.

As far as sample size ya im going to process then crush to around 100 mesh and then sieve and separate multiple samples and average out assays. Figure 1/4 ton to 1/2 ton bulk samples should be good, those of course will be broken down into multi assays and remaining used on pilot mill set ups to check recovery rates. Pretty much am a one man army any more as far as locating the rock, breaking it, removing it, crushing and recovering values, then smelting and refining.

As far as the drilling, no im not doing it by hand, got gasoline powered rock drills that are set up right now to go 5ft deep.

Rock and ore we are after is polymetallic ore veins in your normal quartz and granitoid ore bodies. With Veins that very in width from spidery stock works to 20' wide, just depends on location and vein.

As far as the drilling and blasting i'm looking at doing blasting array with say 6-8 charges plus a few dead/empty holes. Reading the Blasters hand book right now and studying up on blast patterns.

MineMan - 16-12-2018 at 00:01

Ok. So your familer with the sampling procedure I gather, cones, quartering and etc...

The drill cuttings would be a great place to start, if your drill can go 5 feet down with a 1 inch bit... or is it the same bit as a jackleg? That will give you some volume for sampling. With a couple of holes and ANALFO (ammonium nitrate aluminum fuel oil) you will get the quantity.

40 element assay? And then a fire assay for gold?

Yup. Your burner holes in the middle. Your lifters on the bottom and your regular holes. The problem is you can’t do timing with the fuse, And one hole very well might blow your other holes out. For patterns you really want delays, and maybe I am not too creative tonight but I don’t know of an amatuer way to do that...

Nonel diets should cost you about 7 dollars, the delivery charge will be the biggest.

You could use some quick fuse (several feet per second) or better yet electrical quick matches and just set off all the holes at once. It won’t throw, it will be harder to muck, and could damage your back, but I don’t see another way. It should work.

a11051605 - 16-12-2018 at 00:36

Ya been brain storming on timing for the array. Luckly my back ground is electrical/controls so I know I can rig up somthing. Just need afew mill second delay, could maybe program my own controller for the firing sequence, or buy one through some hook ups of mine.

Ya looking into 40 element and fire assay, although I will probably do my own fire assay first then send out anything interesting for 2nd assay/opinion. Payen for all those assays add up quick. Biggest thing is only so much time and money to spend/focus on mine development due to life/expenses, but o well that's how it goes.

Ya pretty familiar with the mine process's as I have been doing it for awhile now, unfortunately had to be all self taught though as most the experianced prospectors I know of are in their 70's and not really getting out and about much anymore.

RogueRose - 16-12-2018 at 02:44

I'm wondering if you couldn't use an arduino to program the timing, using a simple relay switch to send juice from a battery to the ematch.

IDK what MineMan meant about being harder to muck - is he talking about a battery or what? Cables/wire? I'd think a normal 20v powertool battery should work fine and if any question, put 2 in series or just a boost converter to jump the voltage up to 35-60V.

You could also build a voltage multiplier with cap's and diodes and get a nice high voltage driven from a small 20V source. The nice thing about these is you don't need high current to charge the caps, it can do it over a minute or so (even though it's probably only take a few seconds).

Last option are simple SPST switchs lined up in a row and running your finger over them quickly.

morganbw - 16-12-2018 at 11:03

In a younger life, I was actually a mucker.
Remove what was blasted. This is in context with the previous post but it could include other removal of spoil.

MineMan - 16-12-2018 at 15:35

I meant if you shoot all holes at the same time it won’t throw, it will key up, thus making mucking (a mining term for removing the blasted rock) more difficult.

a1105, something you really might want to consider is renting an XRF for a day... I think the fee is only a couple hundred. You can pree grind your samples, map your grades out and figure which samples are worth sending off for an assay.

For gold you can also do the stanus chlorine test.... it won’t give you a quantity, but will tell you if there is gold. I would do the fire assays myself to :)

[Edited on 16-12-2018 by MineMan]