blasting smallish tunnels in hard rock

[Richard Smith]

Anyone here know about blasting person-height&width tunnels in hard
rock?

I have some contacts here (UK), but broadening the casting around for
information. Maybe bringing in North American perspective.
Especially noting how much I have gained here from previous ask about
mine haulage-shafts and skips.

New to me. If I'm pointed in the right direction and told the real
deal(s) to look out for, I can do a lot of my own reading.

Some of the rock here is "killas" - a heated "metamorphosed"
sedimentary rock which is quite brittle. Usually associated with
"wet" mines.
Then there is hard granite. Very hard. A 4-carbide-teeth drill bit
cannot touch some when driven by a rock-drill which can go 1~1/2metres
in minutes with a simple chisel-edged carbide-tipped drill bit. Mines
in that can go a mile out under the sea and be dry.
As best I can explain from what I have seen; being a metallurgist and
welder.

There's something which would be very useful here making everything
possible, so it seems.

Something about electronically timed detonators which can serially
detonate "go off at the same time" charges a few microseconds apart,
which is apparently enough that at the surface only the effect of one
charge is felt.

So pointers on that would be appreciated.

Blasting mine tunnels is done radially here I gather from what I have
seen explained at mining museums - blast from the middle outwards,
sending the fractured rock towards the middle (heard of the central
hole being "reamed" - no charge in it obviously - provides the first
void to collapse the first ring of rock into).

Historically gelignite but noted that "ampho" is usually cheaper now.

Another reason for asking for a North American viewpoint is that folk
are much less restricted there - and therefore you get a lot of very
practically experienced folk. eg. when in Texas my host took me to
the range every morning with two holdalls full of hardware - learned a
lot quickly.
Everyone has to be very stern and restricted here trying to appease
the powers-that-be that everyone is very serious and narrow focussed -
no "plinking" or anything like that - and carries over into methods to
make lighter of rearranging rock.

Searching the Web on my own, I wouldn't know when I am "finding gold"
and when it's rubbish.

If you want to personal-message me, go to my website "weldsmith.co.uk"
and use the "Contact me" form and we can pick up on a private email
chat if you prefer that.

Thanks in advance,
Rich Smith

[Bob La Londe]

Post by Richard Smith
Anyone here know about blasting person-height&width tunnels in hard
rock?
I have some contacts here (UK), but broadening the casting around for
information. Maybe bringing in North American perspective.
Especially noting how much I have gained here from previous ask about
mine haulage-shafts and skips.
New to me. If I'm pointed in the right direction and told the real
deal(s) to look out for, I can do a lot of my own reading.
Some of the rock here is "killas" - a heated "metamorphosed"
sedimentary rock which is quite brittle. Usually associated with
"wet" mines.
Then there is hard granite. Very hard. A 4-carbide-teeth drill bit
cannot touch some when driven by a rock-drill which can go 1~1/2metres
in minutes with a simple chisel-edged carbide-tipped drill bit. Mines
in that can go a mile out under the sea and be dry.
As best I can explain from what I have seen; being a metallurgist and
welder.
There's something which would be very useful here making everything
possible, so it seems.
Something about electronically timed detonators which can serially
detonate "go off at the same time" charges a few microseconds apart,
which is apparently enough that at the surface only the effect of one
charge is felt.
So pointers on that would be appreciated.
Blasting mine tunnels is done radially here I gather from what I have
seen explained at mining museums - blast from the middle outwards,
sending the fractured rock towards the middle (heard of the central
hole being "reamed" - no charge in it obviously - provides the first
void to collapse the first ring of rock into).
Historically gelignite but noted that "ampho" is usually cheaper now.
Another reason for asking for a North American viewpoint is that folk
are much less restricted there - and therefore you get a lot of very
practically experienced folk. eg. when in Texas my host took me to
the range every morning with two holdalls full of hardware - learned a
lot quickly.
Everyone has to be very stern and restricted here trying to appease
the powers-that-be that everyone is very serious and narrow focussed -
no "plinking" or anything like that - and carries over into methods to
make lighter of rearranging rock.
Searching the Web on my own, I wouldn't know when I am "finding gold"
and when it's rubbish.
If you want to personal-message me, go to my website "weldsmith.co.uk"
and use the "Contact me" form and we can pick up on a private email
chat if you prefer that.
Thanks in advance,
Rich Smith

No. Not one bit. I suspect small shaped charges might be the ticket if
blasting were the only option, but the little bit of blasting I've been
around used "cruder" explosives due to cost. Things like bags or urea
dropped down a hole with diesel and blasting caps. Somewhere around my
dad's house is a VHS tape I recorded out in the desert from when Western
rock removed almost the entire south face of Aztec hill. I don't recall
how much urea they said they used any more, but it was a lot. Not much
of a show. Three little puffs of dust out the bore holes, a hint of
movement, and then 30-45 minutes waiting for the dust to clear even
though it was a windy day.

They'd spent weeks talking up their big blast in local stores and bars...

I might see if my dad still has that tape. It might be fun to digitize
and put on YouTube....

350LB of Urea & Diesel GOES POP!

[Richard Smith]

Post by Bob La Londe

Post by Richard Smith
Anyone here know about blasting person-height&width tunnels in hard
rock?
I have some contacts here (UK), but broadening the casting around for
information. Maybe bringing in North American perspective.
Especially noting how much I have gained here from previous ask about
mine haulage-shafts and skips.
New to me. If I'm pointed in the right direction and told the real
deal(s) to look out for, I can do a lot of my own reading.
Some of the rock here is "killas" - a heated "metamorphosed"
sedimentary rock which is quite brittle. Usually associated with
"wet" mines.
Then there is hard granite. Very hard. A 4-carbide-teeth drill bit
cannot touch some when driven by a rock-drill which can go 1~1/2metres
in minutes with a simple chisel-edged carbide-tipped drill bit. Mines
in that can go a mile out under the sea and be dry.
As best I can explain from what I have seen; being a metallurgist and
welder.
There's something which would be very useful here making everything
possible, so it seems.
Something about electronically timed detonators which can serially
detonate "go off at the same time" charges a few microseconds apart,
which is apparently enough that at the surface only the effect of one
charge is felt.
So pointers on that would be appreciated.
Blasting mine tunnels is done radially here I gather from what I have
seen explained at mining museums - blast from the middle outwards,
sending the fractured rock towards the middle (heard of the central
hole being "reamed" - no charge in it obviously - provides the first
void to collapse the first ring of rock into).
Historically gelignite but noted that "ampho" is usually cheaper now.
Another reason for asking for a North American viewpoint is that folk
are much less restricted there - and therefore you get a lot of very
practically experienced folk. eg. when in Texas my host took me to
the range every morning with two holdalls full of hardware - learned a
lot quickly.
Everyone has to be very stern and restricted here trying to appease
the powers-that-be that everyone is very serious and narrow focussed -
no "plinking" or anything like that - and carries over into methods to
make lighter of rearranging rock.
Searching the Web on my own, I wouldn't know when I am "finding gold"
and when it's rubbish.
If you want to personal-message me, go to my website "weldsmith.co.uk"
and use the "Contact me" form and we can pick up on a private email
chat if you prefer that.
Thanks in advance,
Rich Smith

No. Not one bit. I suspect small shaped charges might be the ticket
if blasting were the only option, but the little bit of blasting I've
been around used "cruder" explosives due to cost. Things like bags or
urea dropped down a hole with diesel and blasting caps. Somewhere
around my dad's house is a VHS tape I recorded out in the desert from
when Western rock removed almost the entire south face of Aztec hill.
I don't recall how much urea they said they used any more, but it was
a lot. Not much of a show. Three little puffs of dust out the bore
holes, a hint of movement, and then 30-45 minutes waiting for the dust
to clear even though it was a windy day.
They'd spent weeks talking up their big blast in local stores and bars...
I might see if my dad still has that tape. It might be fun to
digitize and put on YouTube....
350LB of Urea & Diesel GOES POP!
--
Bob La Londe
CNC Molds N Stuff
--
This email has been checked for viruses by AVG antivirus software.
www.avg.com

Sorry - that's "ANFO", as you point out.

"Little puffs of dust" - apparently (my local connections) that's
exactly what you should get.
Exasperated comment that many Company "buy our wonderful product"
videos have plumes of ejected material because it looks good - but is
technically wrong and misleading.

Urea - I was thinking ammonium nitrate?
Apparently mining companies using tonnes of the stuff do their own
mixing.
However there are the made-up "prills" - seen as pink "bits" - for
more modest users it seems.

Shaped charges - not in this application?
The pattern the holes are drilled is doing all the "focusing" to get
optimal result. Cylindrical holes metres long filled with blasting
agent.

The thrill about using the Holman rock-drill - the "Holman Silver 3
Airleg" - N.Am. = "jackleg"

which I didn't mention (?) because I could find no good photos and
didn't take a camera with me down the mine because didn't know I
would be in the granite section (dry - killas section is like being
in a shower at times) and having my first go with a rock-drill -
anyway I ran a hole the size of a stick of gelignite (about 35mm?)
1~1/2metres into the hard granite wall of one of the levels in
minutes -- that was promising with the ex-miner stepping-away after
about a minute, satisfied to leave me running the hole -- the
drilling being parallel in the horizontal and vertical planes to
the central "reference" hole

lead to this next thought - the purpose of hole-drilling which can now
be done is blasting. And there is hope of finding a lode to the side
of the existing workings. Clear so cannot disturb historical workings.

The folk here damn' well know about all this stuff, but looking to
other views. Other cultures of mining. Looking to learn.

I have seen videos of blasting "panels" of rock in quarries.
This was done in quarries near where I grew-up.
When I was ill off school at home during the day, you would hear the
siren going for a couple of minutes, then a "bang". From the
limestone area a few miles away...

As I mentioned, the overall pattern of this blasting here in mining is
radial, about the lengthwise centre of the level being extended (if I
understand rightly - mainly from Geevor Mine museum).

[Leon Fisk]

On Sun, 17 Dec 2023 20:08:02 +0000
Richard Smith <***@void.com> wrote:

<snip>

Post by Richard Smith
The folk here damn' well know about all this stuff, but looking to
other views. Other cultures of mining. Looking to learn.

There are old catalogs and books at Archive.com that might be of
interest. This search should get you started:

https://archive.org/search?query=subject:"mining+tools"

[Richard Smith]

Post by Leon Fisk
On Sun, 17 Dec 2023 20:08:02 +0000
<snip>

Post by Richard Smith
The folk here damn' well know about all this stuff, but looking to
other views. Other cultures of mining. Looking to learn.

There are old catalogs and books at Archive.com that might be of
https://archive.org/search?query=subject:"mining+tools"
--
Leon Fisk
Grand Rapids MI

Looks interesting - will come back to this.

[Richard Smith]

Further to original post:
I have looked on-line.
Going for the very specific search
"electronic timer blasting"
lead me to
"electronic detonator blasting"
with many relevant finds.
Seems is a big industry.
Hopefully by what I learn and by going for more very specific searches
I can find my way into this topic.

One example find is
https://www.epc-groupe.co.uk/products/
where they list many products for blasting.

Different "takes" on the matter are appreciated.

[Jim Wilkins]

"Richard Smith" wrote in message news:***@void.com...

Further to original post:
I have looked on-line.
Going for the very specific search
"electronic timer blasting"
lead me to
"electronic detonator blasting"
with many relevant finds.
Seems is a big industry.
Hopefully by what I learn and by going for more very specific searches
I can find my way into this topic.

One example find is
https://www.epc-groupe.co.uk/products/
where they list many products for blasting.

Different "takes" on the matter are appreciated.

-----------------------------------------
https://miningandblasting.files.wordpress.com/2009/09/rock-excavation-handbook-tunneling.pdf
"Large cut holes are normally drilled by reaming. First, a smaller, for
example, 45mm diameter hole is drilled then
reamed to the final size using a pilot adapter and a reaming bit."

"Big, uncharged cut holes (76 - 127mm dia.) [3-5"] provide an opening for
the blasted, expanding
rock from the surrounding cut holes."

[Richard Smith]

Post by Richard Smith
I have looked on-line.
Going for the very specific search
"electronic timer blasting"
lead me to
"electronic detonator blasting"
with many relevant finds.
Seems is a big industry.
Hopefully by what I learn and by going for more very specific searches
I can find my way into this topic.
One example find is
https://www.epc-groupe.co.uk/products/
where they list many products for blasting.
Different "takes" on the matter are appreciated.
-----------------------------------------
https://miningandblasting.files.wordpress.com/2009/09/rock-excavation-handbook-tunneling.pdf
"Large cut holes are normally drilled by reaming. First, a smaller,
for example, 45mm diameter hole is drilled then
reamed to the final size using a pilot adapter and a reaming bit."
"Big, uncharged cut holes (76 - 127mm dia.) [3-5"] provide an opening
for the blasted, expanding
rock from the surrounding cut holes."

Thanks. That's the sort of thing I was looking for.

[Richard Smith]

Post by Richard Smith
I have looked on-line.
Going for the very specific search
"electronic timer blasting"
lead me to
"electronic detonator blasting"
with many relevant finds.
Seems is a big industry.
Hopefully by what I learn and by going for more very specific searches
I can find my way into this topic.
One example find is
https://www.epc-groupe.co.uk/products/
where they list many products for blasting.
Different "takes" on the matter are appreciated.
-----------------------------------------
https://miningandblasting.files.wordpress.com/2009/09/rock-excavation-handbook-tunneling.pdf
"Large cut holes are normally drilled by reaming. First, a smaller,
for example, 45mm diameter hole is drilled then
reamed to the final size using a pilot adapter and a reaming bit."
"Big, uncharged cut holes (76 - 127mm dia.) [3-5"] provide an opening
for the blasted, expanding
rock from the surrounding cut holes."

I want to give thanks to you and the group for all your guidance and
contributions.
On 17 Dec 2023 all was ahead of me.
On 20 Dec 2023 when you gave the
https://miningandblasting.files.wordpress.com/2009/09/rock-excavation-handbook-tunneling.pdf
link I couldn't understand or follow what it was saying.
With own reading-around - books and online - and help here, it makes
sense now.

So on this first day of 2024 - my best wishes to all of you.
Rich Smith

[Jim Wilkins]

"Richard Smith" wrote in message news:***@richards-air-2.home...

"Jim Wilkins" <***@gmail.com> writes:

I want to give thanks to you and the group for all your guidance and
contributions.
On 17 Dec 2023 all was ahead of me.
On 20 Dec 2023 when you gave the
https://miningandblasting.files.wordpress.com/2009/09/rock-excavation-handbook-tunneling.pdf
link I couldn't understand or follow what it was saying.
With own reading-around - books and online - and help here, it makes
sense now.

So on this first day of 2024 - my best wishes to all of you.
Rich Smith

--------------------------------
It seemed to have been written for miners who already knew how to drill a
hole but not why or where.

This has diagrams of the sequential blast pattern opening up the central
uncharged borehole.
https://www.eoas.ubc.ca/courses/eosc547/lecture-material/Topic4-HardRockTunnellingMethods.pdf

Did you read Hudson Maxim's dynamite book? It's quite funny as long as
mental images of flying body parts don't bother you.

[Richard Smith]

Post by Jim Wilkins
...
Did you read Hudson Maxim's dynamite book? It's quite funny as long as
mental images of flying body parts don't bother you.

I had a quick look, copied the links to my files and bookmarked them
in the browser.
I have insomnia - could wrap up warm and read them.

I've worked in heavy industry and construction, so of nature do dark
humour with the reality of always looking out for yourself and others.

[Jim Wilkins]

"Richard Smith" wrote in message news:***@richards-air-2.home...

I've worked in heavy industry and construction, so of nature do dark
humour with the reality of always looking out for yourself and others.

-------------------------

Maxim was willing to admit that he blew his hand off from inattention caused
by lack of sleep. I put off chainsawing and similar dangerous tasks until
wide awake; this morning I'm posting instead of finishing a job on the roof
for that reason. I regretfully quit night school because enough evening
coffee for 2 demanding classes and the late commute home kept me from
getting enough sleep.

[Richard Smith]

Post by Jim Wilkins
...
Did you read Hudson Maxim's dynamite book? It's quite funny as long as
mental images of flying body parts don't bother you.

I've got 2/3rds of the way through the first one.

There is a message you want me to get ? !
Something you want me to know, which you cannot say yourself but you
know this is exactly the right voice saying it?

There's a few general themes emerging from all those hundreds of
seemingly disparate stories.

[Jim Wilkins]

Post by Jim Wilkins
...
Did you read Hudson Maxim's dynamite book? It's quite funny as long as
mental images of flying body parts don't bother you.

I've got 2/3rds of the way through the first one.

There is a message you want me to get ? !
Something you want me to know, which you cannot say yourself but you
know this is exactly the right voice saying it?

There's a few general themes emerging from all those hundreds of
seemingly disparate stories.

-------------------------------------
No, nothing personal. Really they were the only tales of working and playing
with nitroglycerine that I'd read online, when they appeared on Gutenberg's
recently added page. They are too old to describe current practice, but like
steam engines the evolving tech of those days interests me.

Hudson's brother Hiram took off in a winged and powered airplane before the
Wrights, but they were the first to be able to fly the same plane again.
https://engines.egr.uh.edu/episode/210

Missing fingers was fairly common among young chemistry students -- I still
have all of mine.

[Richard Smith]

Post by Jim Wilkins

Post by Richard Smith
...
There is a message you want me to get ? !
Something you want me to know, which you cannot say yourself but you
know this is exactly the right voice saying it?
There's a few general themes emerging from all those hundreds of
seemingly disparate stories.

No, nothing personal. Really they were the only tales of working and
playing with nitroglycerine that I'd read online,
...

The message I get is similar to the one about oxy-acetylene equipment
- welding and cutting.
You do not mess around with it. You do not improvise. You take it
out of the box and you use it "by numbers" according to instructions.
If it doesn't work as-is you stop.
Oxy-acetylene equipment is a good way to investigate reincarnation.

All other welding equipment - you rig, frig, improvise, adapt, oil
where you have to - all sorts of things.

The situation is vastly more complex for these blasting substances.
But there are some recurrent themes where things went wrong.
Hopefully they will lodge in my mind and activate if I meet like
situation.

There's potassium chlorate preparations in the book I already have -
reprint of Guttman, "Blasting", 1906.
He is dismissive of them, saying don't be distracted off NG-based
media - jelly and dyna.
Hudson Maxim - his treatment of the topic!
Apparently relevant? No. Calibration of judgment - definitely.

Hudson Maxim's eloquent way of saying a lot with a few words:

"Now it happens that there is so much erraticism about high explosive
mixtures with chlorate of potash as a base that the pathway of
invention of such compounds has been strewn with the wreckage of the
hopes and anatomy of their inventors."

[Jim Wilkins]

"Richard Smith" wrote in message news:***@void.com...

Hudson Maxim's eloquent way of saying a lot with a few words:

"Now it happens that there is so much erraticism about high explosive
mixtures with chlorate of potash as a base that the pathway of
invention of such compounds has been strewn with the wreckage of the
hopes and anatomy of their inventors."
------------------------------------
His style reminds me of Ambrose Bierce.

"The poets would have us believe that all of the great inventors and
discoverers, scientists and philosophers, have been far inferior to the
poets. The poets would have us believe that all the triumphs of chemistry
and mechanics have been small compared with the triumphs of poetry. The
poets would have us believe that the invention of the phonograph, of the
telephone, of wireless telegraphy, the discovery of radium and the X-ray,
the discovery of gravitation, are not equal to such triumphs of the poets as
“Aurora Leigh,” “Curfew Must Not Ring Tonight,” and “The May Queen.”
-HM

[Jim Wilkins]

"Jim Wilkins" wrote in message news:un2c3s$2u4u6$***@dont-email.me...

His style reminds me of Ambrose Bierce.

https://www.gutenberg.org/files/972/972-h/972-h.htm

[Richard Smith]

Post by Jim Wilkins
His style reminds me of Ambrose Bierce.
https://www.gutenberg.org/files/972/972-h/972-h.htm

You are a cultured person.
I have a simple technical-algorithm mind which obsesses on bashing,
banging and other low-tech treatments, all serving fixations too
narrow for anyone else to have even seen the question could be
identified - until I come up with something "new and revolutionary" by
reason of no-one ever having been there to pursue such an archane
question...
:-)

[Jim Wilkins]

Post by Jim Wilkins
His style reminds me of Ambrose Bierce.
https://www.gutenberg.org/files/972/972-h/972-h.htm

You are a cultured person.
I have a simple technical-algorithm mind which obsesses on bashing,
banging and other low-tech treatments, all serving fixations too
narrow for anyone else to have even seen the question could be
identified - until I come up with something "new and revolutionary" by
reason of no-one ever having been there to pursue such an archane
question...
:-)
---------------------------
At a Mensa party several of us who had made careers of innovation and
problem solving considered the question of how to design a computer
algorithm to assist us. We concluded that we don't know where our new ideas
come from, subconscious memory associations can't account for all of them.
As Taylor Swift wrote in the Pattie Boyd interview:
"But there are mystical, magical moments, inexplicable moments when an idea
that is fully formed just pops into your head."

Since industrial innovation is usually too competitive to reveal in print
I've looked at artistic innovation, such as the analysis of song meanings,
as much for why they chose their words as what they meant to say. I'm
convinced that Bob Dylan's lyrics were chosen to rhyme and prompt the
audience to apply their own interpretations to them. Last night on TV a
program on painter Edward Hopper held that the critics had seen more in his
paintings than it was eventually revealed that he intended.

https://blog.artsper.com/en/a-closer-look/artwork-analysis-nighthawks-by-edward-hopper/
The enigmatic couple are the painter and his wife, who was also a talented
artist and capable chronicler of his work. She wouldn't let him use any
other woman as a model.

[Richard Smith]

Post by Jim Wilkins
https://blog.artsper.com/en/a-closer-look/artwork-analysis-nighthawks-by-edward-hopper/
The enigmatic couple are the painter and his wife, who was also a
talented artist and capable chronicler of his work. She wouldn't let
him use any other woman as a model.

Funnily enough, I know of this artist.
HIs work is sufficiently distinctive to have stuck in my mind.

[Jim Wilkins]

"Richard Smith" wrote in message news:***@void.com...

You are a cultured person.
I have a simple technical-algorithm mind which obsesses on bashing,
banging and other low-tech treatments, all serving fixations too
narrow for anyone else to have even seen the question could be
identified - until I come up with something "new and revolutionary" by
reason of no-one ever having been there to pursue such an archane
question...
:-)
---------------------------

You may be a product of your environment. By Alistair Cooke:
https://www.bbc.co.uk/programmes/articles/2MKhm99hgpBrV79K47Mycbh/persian-poets-need-not-apply-29-march-2002

"None of my friends in England had ever heard of biology until and unless
they were going into a science which in those days put them outside the pale
of cultivated company."

"I'm sure this has all changed since nearly a half a century ago when the
late CP Snow raised a cultural storm, especially in the ancient
universities, by saying that in England then there were two cultures that
lived side by side in mutual incomprehension and even hostility."

"There was the culture of literary arts people who think of themselves as
the cultivated and there were the physical scientists who may know little
literature but are amazed at the narrowness, the constraint, the literary
intellectuals' ignorance of so much of the life and the world about them."

"The man - his name was [Harold] Macmillan - wrote in his diary, after he'd
spent some days and evenings with the general [Eisenhower], he wrote: "He is
a man of charm and candour and determination but I fear woefully
ill-educated."

"But whereas Mr Macmillan found Eisenhower deficient I imagine in quotations
from Virgil and Wordsworth, he was woefully ill-educated in mathematics,
engineering, strategy and tactics, especially the economics of industrial
warfare about which Eisenhower's prescience had made General Marshall insist
he become supreme commander."

Macmillan's reaction to Americans:
"We, my dear Crossman, are the Greeks in the American empire. You will find
the Americans much as the Greeks found the Romans—great big, vulgar bustling
people, more vigorous than we are and also more idle, with more unspoiled
virtues, but also more corrupt. We must run AFHQ (Allied Forces
Headquarters) as the Greek slaves ran the operations of the Emperor
Claudius".

Americans weren't totally ignorant of the classics, Patton used Caesar's
operations as a guide to where the low ground was firm enough for vehicles,
and raced him to bridge the Rhine.

[Richard Smith]

I read that bit... :-)

[Jim Wilkins]

"Richard Smith" wrote in message news:***@void.com...

https://www.epc-groupe.co.uk/products/
where they list many products for blasting.
------------------------------

This shows the speed of non-electric blasting cord:

[Snag]

Post by Richard Smith
https://www.epc-groupe.co.uk/products/
where they list many products for blasting.
------------------------------
http://youtu.be/i6k26SJFyB8

IIRC primacord detonation head propagates at about 2000 meters/second .
I only got to play with it once or twice but it sure was fun !

[Jim Wilkins]

Post by Richard Smith
https://www.epc-groupe.co.uk/products/
where they list many products for blasting.
------------------------------
http://youtu.be/i6k26SJFyB8

IIRC primacord detonation head propagates at about 2000 meters/second .
I only got to play with it once or twice but it sure was fun !

[Richard Smith]

For what it's worth - identified the rock-drill I used.

http://weldsmith.co.uk/tech/minerals/condurrow/231207_rockdrill1st/231224_holman_silver_900.html
"rock-drill of 07Dec2023 - Holman Silver 900"

One of the volunteers was a driller and said this machine is only
usable on hard granite. That on any other rock - which in Cornwall
would mean the "killas" which is the "country rock" - is a
metamorphosed sedimentary rock - it is difficult to control.
Use the popular smaller "303" - which is easier to carry too, etc.

Rich S

[Jim Wilkins]

"Richard Smith" wrote in message news:***@richards-air-2.home...

For what it's worth - identified the rock-drill I used.

http://weldsmith.co.uk/tech/minerals/condurrow/231207_rockdrill1st/231224_holman_silver_900.html
"rock-drill of 07Dec2023 - Holman Silver 900"

One of the volunteers was a driller and said this machine is only
usable on hard granite. That on any other rock - which in Cornwall
would mean the "killas" which is the "country rock" - is a
metamorphosed sedimentary rock - it is difficult to control.
Use the popular smaller "303" - which is easier to carry too, etc.

Rich S

---------------------------------------
https://www.sunritadrillbit.com/holman-303-rock-drill/
What is "lofty-quality steel"?

[Richard Smith]

Post by Jim Wilkins
---------------------------------------
https://www.sunritadrillbit.com/holman-303-rock-drill/
What is "lofty-quality steel"?

This looks to be a copy (something like a copy?) of the Holman Silver 303.

The expression in English about the drill is brilliant.

Air-powered, at one place it's got an internal petrol (gasoline)
engine - in another it has an internal diesel engine ... (!)

I imagine "lofty quality" is excessive use of a thesaurus to find
synonyms for "high" - "high quality"

Rich S

[Jim Wilkins]

Post by Jim Wilkins
---------------------------------------
https://www.sunritadrillbit.com/holman-303-rock-drill/
What is "lofty-quality steel"?

This looks to be a copy (something like a copy?) of the Holman Silver 303.

The expression in English about the drill is brilliant.

Air-powered, at one place it's got an internal petrol (gasoline)
engine - in another it has an internal diesel engine ... (!)

I imagine "lofty quality" is excessive use of a thesaurus to find
synonyms for "high" - "high quality"

Rich S
---------------------------------
I would be worse translating to or from technical French or German. I
subscribed to the German language version of the Daimler in-house magazine
and couldn't find many of the high tech words in a dictionary. Although much
of English descended from Saxon German the modern usage is considerably
different, they don't translate word for word the way French sometimes does.
https://emercedesbenz.com/tag/high-tech-report/

I watched a pile driver that was obviously a Diesel from the black smoke
puffs. Are Diesel hammers practical for horizontal drilling in tunnels?

[Richard Smith]

Post by Richard Smith

Post by Jim Wilkins
---------------------------------------
https://www.sunritadrillbit.com/holman-303-rock-drill/
What is "lofty-quality steel"?

This looks to be a copy (something like a copy?) of the Holman Silver 303.
The expression in English about the drill is brilliant.
Air-powered, at one place it's got an internal petrol (gasoline)
engine - in another it has an internal diesel engine ... (!)
I imagine "lofty quality" is excessive use of a thesaurus to find
synonyms for "high" - "high quality"
Rich S
---------------------------------
I would be worse translating to or from technical French or German. I
subscribed to the German language version of the Daimler in-house
magazine and couldn't find many of the high tech words in a
dictionary. Although much of English descended from Saxon German the
modern usage is considerably different, they don't translate word for
word the way French sometimes does.
https://emercedesbenz.com/tag/high-tech-report/
I watched a pile driver that was obviously a Diesel from the black
smoke puffs. Are Diesel hammers practical for horizontal drilling in
tunnels?

The "Delmag" type pile-driver...

They work by the piston falling in gravity.
For a horizontal cylinder there could be a spring or gas pressure.

The problem would be clean combustion.
You wouldn't want sooty and tarry waste gases down a mine.

Maybe use something like propane, with spark-ignition.
Would still need ventilation - would get through oxygen in the air.

Beauty of air-tool is exhausts breatable air and the tool gets cooler
as it works - makes it handlable for hard work.

I think suffer the inefficiency of compressed air systems for the
simplicity, robustness, safety, avoidance of environmental problems
down the mine, etc.

My impression is compressed air systems are about 10% efficient.
eg. 3kW into the compressor motor to get the equivalent of about 300W
of electrical power in something like an angle-grinder.

I've never seen a diesel hammer in action.
Seen air-driven and hydraulic.

[Joe Gwinn]

Post by Richard Smith

Post by Richard Smith

Post by Jim Wilkins
---------------------------------------
https://www.sunritadrillbit.com/holman-303-rock-drill/
What is "lofty-quality steel"?

This looks to be a copy (something like a copy?) of the Holman Silver 303.
The expression in English about the drill is brilliant.
Air-powered, at one place it's got an internal petrol (gasoline)
engine - in another it has an internal diesel engine ... (!)
I imagine "lofty quality" is excessive use of a thesaurus to find
synonyms for "high" - "high quality"
Rich S
---------------------------------
I would be worse translating to or from technical French or German. I
subscribed to the German language version of the Daimler in-house
magazine and couldn't find many of the high tech words in a
dictionary. Although much of English descended from Saxon German the
modern usage is considerably different, they don't translate word for
word the way French sometimes does.
https://emercedesbenz.com/tag/high-tech-report/
I watched a pile driver that was obviously a Diesel from the black
smoke puffs. Are Diesel hammers practical for horizontal drilling in
tunnels?

The "Delmag" type pile-driver...
They work by the piston falling in gravity.
For a horizontal cylinder there could be a spring or gas pressure.
The problem would be clean combustion.
You wouldn't want sooty and tarry waste gases down a mine.
Maybe use something like propane, with spark-ignition.
Would still need ventilation - would get through oxygen in the air.
Beauty of air-tool is exhausts breatable air and the tool gets cooler
as it works - makes it handlable for hard work.
I think suffer the inefficiency of compressed air systems for the
simplicity, robustness, safety, avoidance of environmental problems
down the mine, etc.
My impression is compressed air systems are about 10% efficient.
eg. 3kW into the compressor motor to get the equivalent of about 300W
of electrical power in something like an angle-grinder.
I've never seen a diesel hammer in action.
Seen air-driven and hydraulic.

I've seen diesel pile-drivers in action. Like this:

Joe Gwinn

[Gerry]

Post by Joe Gwinn

Post by Richard Smith

Post by Richard Smith

Post by Jim Wilkins
---------------------------------------
https://www.sunritadrillbit.com/holman-303-rock-drill/
What is "lofty-quality steel"?

This looks to be a copy (something like a copy?) of the Holman Silver 303.
The expression in English about the drill is brilliant.
Air-powered, at one place it's got an internal petrol (gasoline)
engine - in another it has an internal diesel engine ... (!)
I imagine "lofty quality" is excessive use of a thesaurus to find
synonyms for "high" - "high quality"
Rich S
---------------------------------
I would be worse translating to or from technical French or German. I
subscribed to the German language version of the Daimler in-house
magazine and couldn't find many of the high tech words in a
dictionary. Although much of English descended from Saxon German the
modern usage is considerably different, they don't translate word for
word the way French sometimes does.
https://emercedesbenz.com/tag/high-tech-report/
I watched a pile driver that was obviously a Diesel from the black
smoke puffs. Are Diesel hammers practical for horizontal drilling in
tunnels?

The "Delmag" type pile-driver...
They work by the piston falling in gravity.
For a horizontal cylinder there could be a spring or gas pressure.
The problem would be clean combustion.
You wouldn't want sooty and tarry waste gases down a mine.
Maybe use something like propane, with spark-ignition.
Would still need ventilation - would get through oxygen in the air.
Beauty of air-tool is exhausts breatable air and the tool gets cooler
as it works - makes it handlable for hard work.
I think suffer the inefficiency of compressed air systems for the
simplicity, robustness, safety, avoidance of environmental problems
down the mine, etc.
My impression is compressed air systems are about 10% efficient.
eg. 3kW into the compressor motor to get the equivalent of about 300W
of electrical power in something like an angle-grinder.
I've never seen a diesel hammer in action.
Seen air-driven and hydraulic.

http://youtu.be/VmIhSh_7gVA
Joe Gwinn

From my experience about sixty years ago, the crew opperating a
"Delmag" pile driver, wear black (beige when new) coverals!

[Richard Smith]

Post by Gerry

Post by Joe Gwinn

Post by Richard Smith

...

I've never seen a diesel hammer in action.
Seen air-driven and hydraulic.

http://youtu.be/VmIhSh_7gVA
Joe Gwinn

From my experience about sixty years ago, the crew opperating a
"Delmag" pile driver, wear black (beige when new) coverals!

From grease lubrication and from part-burned fuel?

[Jim Wilkins]

Post by Gerry

Post by Joe Gwinn

Post by Richard Smith

...

I've never seen a diesel hammer in action.
Seen air-driven and hydraulic.

http://youtu.be/VmIhSh_7gVA
Joe Gwinn

From my experience about sixty years ago, the crew opperating a
"Delmag" pile driver, wear black (beige when new) coverals!

From grease lubrication and from part-burned fuel?
-------------------------------

The video shows what I remembered, except for the smoke color. The firing
rate is at or below once a second so the chamber walls may not warm to
operating temperature quickly.

Last night I dreamed about being offered a very inexpensive batch of used
lawnmowers with a strange electric drive, powered by a 2 cylinder rotary
(like WW1) engine built into the rotor of the alternator, as simple to make
as a model airplane engine, and cheap surplus 90V electric motors to spin
the blade. The seller's explanations all made sense, but I woke up before he
answered if it required unavailable carbon brushes or castor oil.

Speaking of weird lawnmowers, I helped restore an MTD Yard Bug.
https://www.ebay.com/itm/175849445818

[Leon Fisk]

On Thu, 28 Dec 2023 08:00:42 -0500
"Jim Wilkins" <***@gmail.com> wrote:

<snip>

Post by Jim Wilkins
Speaking of weird lawnmowers, I helped restore an MTD Yard Bug.
https://www.ebay.com/itm/175849445818

Only saw one once mowing in a ditch... but thought the "Hover Mowers"
were pretty unusual😉

https://www.ebay.com/sch/i.html?_nkw=flymo+hover+mower&_sop=12

[Snag]

Post by Leon Fisk
On Thu, 28 Dec 2023 08:00:42 -0500
<snip>

Post by Jim Wilkins
Speaking of weird lawnmowers, I helped restore an MTD Yard Bug.
https://www.ebay.com/itm/175849445818

Only saw one once mowing in a ditch... but thought the "Hover Mowers"
were pretty unusual😉
https://www.ebay.com/sch/i.html?_nkw=flymo+hover+mower&_sop=12

My uncle had one of those back in the late 50's (?) or maybe early 60's
. As I recall it did a reasonably decent job .

[Richard Smith]

You know you might be overdoing arcane interests when you get strange
dreams on the topic... :-)

[Jim Wilkins]

"Richard Smith" wrote in message news:***@richards-air-2.home...

You know you might be overdoing arcane interests when you get strange
dreams on the topic... :-)

---------------------------
While visiting Britain my sister bought a fairly technical book on the
Spitfire at the IWM for Christmas and I've been reading it, but it's not
related to WW1 rotaries or lawnmowers.

She also caught Covid there.

[Snag]

Post by Richard Smith
You know you might be overdoing arcane interests when you get strange
dreams on the topic...  :-)
---------------------------
While visiting Britain my sister bought a fairly technical book on the
Spitfire at the IWM for Christmas and I've been reading it, but it's not
related to WW1 rotaries or lawnmowers.
She also caught Covid there.

Did you know that a Harley 45° V-twin is actually a partial radial
engine ?

[Jim Wilkins]

"Snag" wrote in message news:uml25o$i904$***@dont-email.me...

Did you know that a Harley 45° V-twin is actually a partial radial
engine ?
Snag
------------------------
Sort of. The forked connecting rod puts both cylinders in the same plane,
but the V-12 Merlin is built that way too. A real radial has one master
connecting rod that rides on the crank pin and the other rod "big ends" are
on pins around it.
http://www.aviation-history.com/engines/radial.htm

The lawnmower engine/alternator was a 2 cycle opposed twin, like this;
https://www.ebay.com/itm/235110607332
but set up as a rotary, with the cylinders part of the alternator rotor
casting. I have no idea what prompted that notion but the seller's
explanations all seemed logical even after I woke up, which is unusual.

I saw a one cylinder, 4-stroke Saito FA-80 model engine at a flea market and
examined it until the seller dropped the price to $30. At that price it
doesn't have to run, just sit on a shelf with other curios.
https://saito-engines.info/

This interview mentions fully developed ideas popping up.
https://www.harpersbazaar.com/culture/features/a22020940/taylor-swift-interviews-pattie-boyd/
"There are definitely moments when it’s like this cloud of an idea comes and
just lands in front of your face, and you reach up and grab it."

Often while I was in the shower and couldn't write it down immediately.

I found that link while researching song inspirations, Pattie Boyd was the
subject of quite a few. In the 60's I was the tech/roadie for a film maker
who was doing music videos so I saw something of the off stage lives of
musicians on tour, and was happy -not- to be one. His studio partly imitated
Warhol's Factory, minus the drugs.

[Richard Smith]

Post by Jim Wilkins
...
She also caught Covid there.

Is everywhere and endemic now.
I assumed I must have had it without symptoms having worked all the
way through covid19 pandemic - then a year ago got something which
really left me flattened for a week which was covid. Had to stay warm
under two duvets to mitigate the discomfort of it.
It clearly mutates "like mad" so comes in waves as variants evade
natural immunity to previousl strains.
We are getting "normal" "colds" again - streaming but only for a day
or so. Immune systems back up and running after the "lockdowns" which
if prolonged would have themselves lead to higher mortality. Everyone
without honed immunity and when a virus does break through it would be
at the worst time, likely mid-winter, and we would have had the huge
wave of serious illness and mortality we sought to avoid.
Looking back - slowing the initial propagation, at huge effort, was a
good idea. Turning it into a "Wow this is good - let's do it for
ever" was manifestation of general pervasive institutional stupidity.

Hope she enjoyed time in England / Britain.

[Snag]

Post by Richard Smith
You know you might be overdoing arcane interests when you get strange
dreams on the topic... :-)

Well , I wouldn't call my dreams about guns "strange" ... disturbing
maybe . But not strange .

[Richard Smith]

I remember a couple of disturbed dreams during my doctoral years.

In one I was on holiday in Yugoslavia - was during the break-up.
Given I fondly remember Yugoslavia.
I was crawling between rocks try to admire some monastry or something
like that while bullets went overhead.

In another I was in a laboratory which was all brown dark and dusty,
hopelessly cramped so you could only move sideways in some places and
the floor kept collapsing - your foot kept going through the
floorboards.

It is plausible that these were connected to what was happening.
The situation was politically tense during my research.

The workshops were a mess. Only had to be gone a few days and every
machine was - well, motors and things ran, but saw blades had not a
tooth left due to misuse, coolant was run-out and the machines were
jammed-full of swarf, etc.
I'd have to do a lot of "housekeeping", refill soluable-oil coolants -
and get out my own sawblades to do the proper cuts through a lot of
plate steel (then put the toothless on back in - they'd reduce a good
blade to the same state in minutes to an hour anyway).

[Jim Wilkins]

"Richard Smith" wrote in message news:***@richards-air-2.home...

I remember a couple of disturbed dreams during my doctoral years.

In one I was on holiday in Yugoslavia - was during the break-up.
Given I fondly remember Yugoslavia.
I was crawling between rocks try to admire some monastry or something
like that while bullets went overhead.

In another I was in a laboratory which was all brown dark and dusty,
hopelessly cramped so you could only move sideways in some places and
the floor kept collapsing - your foot kept going through the
floorboards.

It is plausible that these were connected to what was happening.
The situation was politically tense during my research.

The workshops were a mess. Only had to be gone a few days and every
machine was - well, motors and things ran, but saw blades had not a
tooth left due to misuse, coolant was run-out and the machines were
jammed-full of swarf, etc.
I'd have to do a lot of "housekeeping", refill soluable-oil coolants -
and get out my own sawblades to do the proper cuts through a lot of
plate steel (then put the toothless on back in - they'd reduce a good
blade to the same state in minutes to an hour anyway).

------------------------------
The Goes Wrong Show. I was put in charge of an open-access company model
shop that fit that description. You can't cut a rotary lawnmower blade on a
bandsaw at woodcutting speed, though someone kept trying. The gearbox was
broken so I couldn't drop it to the lowest speed. Fortunately the electrical
engineers didn't understand and weren't tempted to abuse the other machines.

In the sci-fi novel The Mote in God's Eye the aliens show the Earthlings a
museum of technology, in which the chief engineer notices that everything is
defective. It's a test of mechanical aptitude, which for the aliens
classifies one as Aspergic with no interpersonal skills. They are amazed
that he can also function as a supervisor. As an electronic technician I had
to be careful to not slip into that bin, thus my exposure to the arts.

[Jim Wilkins]

"Jim Wilkins" wrote in message news:ummjvq$rp7s$***@dont-email.me...

"Richard Smith" wrote in message news:***@richards-air-2.home...

The workshops were a mess. Only had to be gone a few days and every
machine was - well, motors and things ran, but saw blades had not a
tooth left due to misuse, coolant was run-out and the machines were
jammed-full of swarf, etc.
I'd have to do a lot of "housekeeping", refill soluable-oil coolants -
and get out my own sawblades to do the proper cuts through a lot of
plate steel (then put the toothless on back in - they'd reduce a good
blade to the same state in minutes to an hour anyway).

---------------------------
I bought a how-to book, whose title I apparently don't remember well enough
for Google, that turned out to be a British socialist fantasy of communal
ownership of all lawn and garden equipment, to avoid the alleged waste of
everyone buying their own. I suspect it was written out of frustration that
the neighbors had learned not to lend anything to the author.

[Gerry]

Post by Richard Smith

Post by Gerry

Post by Joe Gwinn

Post by Richard Smith

...

I've never seen a diesel hammer in action.
Seen air-driven and hydraulic.

http://youtu.be/VmIhSh_7gVA
Joe Gwinn

From my experience about sixty years ago, the crew opperating a
"Delmag" pile driver, wear black (beige when new) coverals!

From grease lubrication and from part-burned fuel?

Black rain!

[Richard Smith]

Post by Gerry

Post by Richard Smith
...

Post by Gerry
From my experience about sixty years ago, the crew opperating a
"Delmag" pile driver, wear black (beige when new) coverals!

From grease lubrication and from part-burned fuel?

Black rain!

The exhaust has thick liquidy raining-down hydrocarbon residues?

[Gerry]

Post by Richard Smith

Post by Gerry

Post by Richard Smith
...

Post by Gerry
From my experience about sixty years ago, the crew opperating a
"Delmag" pile driver, wear black (beige when new) coverals!

From grease lubrication and from part-burned fuel?

Black rain!

The exhaust has thick liquidy raining-down hydrocarbon residues?

Goo description.

[Jim Wilkins]

"Richard Smith" wrote in message news:***@void.com...

My impression is compressed air systems are about 10% efficient.
eg. 3kW into the compressor motor to get the equivalent of about 300W
of electrical power in something like an angle-grinder.

------------------------------
I saw about 20%, comparing the metered 2.48KW of my air compressor to the
claimed 500W of an electric angle grinder. The time to grind welds was
similar for both tools. I didn't measure carefully because I can't fine tune
the process, only choose between them.

I read an analysis of a proposed compressed air automotive drive that said
the energy loss was mainly from compression heating and expansion cooling,
and in the installation they proposed insulation and a heat exchanger would
increase efficiency, for instance if the compressed air remained hot its
energy would be retained. PV=nRT. Compound steam engines were developed to
reduce the loss from steam cooling the cylinders as it expanded.

[Jim Wilkins]

"Richard Smith" wrote in message news:***@void.com...

I've never seen a diesel hammer in action.
Seen air-driven and hydraulic.

-----------------------------
https://en.wikipedia.org/wiki/Paslode_Impulse

[Leon Fisk]

On Wed, 27 Dec 2023 23:10:16 +0000
Richard Smith <***@void.com> wrote:

<snip>

Post by Richard Smith
I think suffer the inefficiency of compressed air systems for the
simplicity, robustness, safety, avoidance of environmental problems
down the mine, etc.
My impression is compressed air systems are about 10% efficient.
eg. 3kW into the compressor motor to get the equivalent of about 300W
of electrical power in something like an angle-grinder.

See the Taylor Hydraulic Air Compressor for some interesting reading. A
patent with some info and related pointers here:

https://patents.google.com/patent/US4797563A/en

and an old report:

https://archive.org/details/IllustratedDescriptionOfTheTaylorHydraulicAirCompressorAndTransmission

[BobEngelhardt]

Post by Leon Fisk
See the Taylor Hydraulic Air Compressor for some interesting reading. A
https://patents.google.com/patent/US4797563A/en
https://archive.org/details/IllustratedDescriptionOfTheTaylorHydraulicAirCompressorAndTransmission

That's SO neat! So out-of-the-box! An air compressor with no rotating
parts.

One of the best features: the air pressure is independent of the head of
the water power source. The air pressure is determined by the depth of
shaft that the compressor is housed in. The head determines the flow &
power, but not the pressure.

[Leon Fisk]

On Fri, 29 Dec 2023 10:27:20 -0500

Post by BobEngelhardt
That's SO neat! So out-of-the-box! An air compressor with no rotating
parts.
One of the best features: the air pressure is independent of the head of
the water power source. The air pressure is determined by the depth of
shaft that the compressor is housed in. The head determines the flow &
power, but not the pressure.

I put another small doc here (5 images) about the Victoria Mine
installation. It's from scraps I picked up from a friend in the area:

https://postimg.cc/gallery/Q3mhSXK

[BobEngelhardt]

Post by Leon Fisk
I put another small doc here (5 images) about the Victoria Mine
https://postimg.cc/gallery/Q3mhSXK

Thanks. It was interesting, but missing some referenced figures. So I
went looking for the article. I found it here:
https://archive.org/details/miningscientific93sanfuoft/page/204/mode/2up?view=theater

But it is what you posted - i.e. missing some figures. Oh well.

[Leon Fisk]

On Sat, 30 Dec 2023 15:56:36 -0500
BobEngelhardt <***@comcast.net> wrote:

<snip>

Post by BobEngelhardt
Thanks. It was interesting, but missing some referenced figures. So I
https://archive.org/details/miningscientific93sanfuoft/page/204/mode/2up?view=theater
But it is what you posted - i.e. missing some figures. Oh well.

I had access to two "scrap books" from the Victoria Mine for a
short period a long time ago and scanned them. It had all sorts of
compiled news articles, ephemera concerning the mine. They were all
clippings in various shapes and not always easy to decipher how they
originally went together. I likely have the "missing" items just didn't
know where they belonged🤷

I used to vacation in the area and collected several more recent books
on the subject along with other odds & ends. It was a long time ago...

[Jim Wilkins]

"BobEngelhardt" wrote in message news:ummogp$sclg$***@dont-email.me...

That's SO neat! So out-of-the-box! An air compressor with no rotating
parts.

-----------------------------

The same principle creates vacuum.
https://www.flinnsci.com/products/apparatus/laboratory-equipment/water-aspirators/

Before water use appeared on sewage bills it was a cheap, zero maintenance
way to evaporate water or solvent from a solution without risking
contamination or condensation damage to a mechanical vacuum pump.

A jet of steam sucking in water can raise the water's velocity and kinetic
energy high enough to force open a check valve into the boiler that provided
the steam, thus it's a feed pump with no moving parts except the control
valves.
https://en.wikipedia.org/wiki/Injector

On steam locomotives it was usually more practical to use a vertical jet of
cylinder exhaust steam at the base of the stack to increase the draft
through the firebox than to condense and reuse it, since smokestacks had to
be short enough to clear bridges and tunnels and air-cooled condensers were
bulky and fragile. This is why the stack puffed. The exception was trains
passing through large deserts.

https://en.wikipedia.org/wiki/Henri_Giffard
The Wright's achievement was powered flight on wings, manned ballooning
began in 1783.

[Peter Fairbrother]

Post by Snag

Post by Richard Smith
https://www.epc-groupe.co.uk/products/
where they list many products for blasting.
------------------------------
http://youtu.be/i6k26SJFyB8

erm, probably not quite.

They may well have used Nonel for the leadline from the exploder to the
trunklines along the bridge, and possibly for the downlines from the
trunklines to the charges, but the trunklines along the bridge were
detcord, not nonel.

tl-dr:

at 04s18f the trunkline on the nearest section detonates. It is clearly
not a nonel detonation, far too visible and extensive for anything but a
detcord detonation. (nonel detonations are hard to see in daylight,
especially at a distance).

Note also that the detonation is both begun and over within the frame,
there is no visible travel along the trunkline to be seen.

At 30 fps one frame takes 33ms; the main span is 50m, so at 6km/s the
detonation takes 8ms; the detonation is over well within one frame,
though its effects may take longer to manifest.

at 04s19f the trunkline on the center section detonates.

at 04s21f the trunkline on the far section detonates.

The delays between the sections are deliberate. One reason for using
delays is to minimise acoustic and overpressure loads.

at 05s00f the first two main charges blow

at 05s01f the next two charges blow

at 05s02f the last two charges blow

To step single frames in youtube pause the video and use the < and > keys

Post by Snag
IIRC primacord detonation head propagates at about 2000 meters/second .
I only got to play with it once or twice but it sure was fun !

Detcord/Primacord (usually plasticised PETN, loadings for transfer cord
go from about 1.5 gram per meter to about 10 g/m, effects cords go to
about 50 g/m) is usually about 6 km/s or a little higher.

Nonel (which is a tube dusted on the inside with PETN powder held in
place by electrostatic attraction) is about 2,100 m/s

You can hold detonating nonel in your bare hand, though I'd recommend
gloves. Try that with detcord and you will lose fingers at best.

Nonel speed:

Peter Fairbrother

[Richard Smith]

Post by Peter Fairbrother

...

...

...
Peter Fairbrother

Done my Winter / xmas / lurghi season "asperg"!!!

Last year it was "Froude number" (basic hydrodynamics) related to an unusually rapid boat I worked on.
http://weldsmith.co.uk/tech/marine/221231_fhs/221231_froudehs_eg.html

This years is done!
Moving to West Cornwall it had to be
http://weldsmith.co.uk/tech/minerals/tunneldb_learn/240103_blast_info.html

I was in a pub in Camborne with a lot of ex (and some current) tin
miners. Who were explaining thing like "You just stick a stick of
dynamite to it with a lump of clay and it does a job" and "No, we
couldn't use gelignite in South Crofty - too hot - the rock was at
about 80degrees - it would have gone off by itself before we finished
loading it" (that would be an "ooops") - and the sort of things kindly
Cornish ex-miners will explain over a few pints of beer.

So I am really happy with what I did through the journey through the
shortest days of the year :-)

[Jim Wilkins]

"Richard Smith" wrote in message news:***@void.com...

I was in a pub in Camborne with a lot of ex (and some current) tin
miners. ...

-------------------------

I first read that as Cambronne, a French name from British military history.
https://www.napoleon-series.org/research/miscellaneous/c_cambronne.html

Victor Hugo dramatically fictionalized the event and added the "Word of
Cambronne" in Les Miserables.

[Richard Smith]

Jim - I lost your message - but I want to say to all of you how happy
I am.
The shortest days are over and the days are visibly lengthening, the
cold (virus) season is running its course, the new year has started
and thoughts turn to its opportunities.
It doesn't matter that any one study - eg. any one book or article -
is read to completion, because the collage of pieces so far got me
where I need to be.
The topic "full-on mission" is a couple of days behind me now.

I went back to the mine and all was good, then in the eve. went to the
group at the working persons' club where posed with the guy and his
6ft rock-drill-bit - nd there was the lady sat at the bar with a
couple of rocks in front of her on the bar (maybe that's a "pulling"
technique used by ladies here?!)

So simply wanted to say to all - thanks.

[Richard Smith]

I forgot to comment the obvious - when I set out I didn't know what
the goal looked like - then I realised I was there and it had come
into view.

"millisecond-timed detonators" set me going - idea that it is possible
to blast when there are buildings up above at the surface
(at the surface the maximum effect is the power of one charge is timed
milliseconds apart - yet at the blast location the effect for the
tunneling is the sum of all blasts).

However, the "learning payload" took me to realising this is boath
very expensive and far too complicated for learning "per-blast"

Then realising the answer is right there - in rock where "nothing is
going on" - drill a pattern of holes and blast one at a time - thereby
needing on a "cheap" single "no timing" detonator - and looking at
what each blast does - what you intended and what you see and why.
Lots of learning.

As I said, I had no idea what the destination looked like then you
realise you are looking at it "clear as daylight".

The comments and inputs prompted the path to finding I was at "the
goal" (for now).

[Jim Wilkins]

"Richard Smith" wrote in message news:***@void.com...

"millisecond-timed detonators" set me going - idea that it is possible
to blast when there are buildings up above at the surface
(at the surface the maximum effect is the power of one charge is timed
milliseconds apart - yet at the blast location the effect for the
tunneling is the sum of all blasts).

--------------------------------

As I understood it, the blasts are timed 0.1-0.5 Sec apart to let the rock
fragments exit the central opening at 40-70 m/Sec, and the charges are large
enough to fragment the rock but not so large they pulverize and pack it
against the opposite wall.

[Richard Smith]

Post by Richard Smith
"millisecond-timed detonators" set me going - idea that it is possible
to blast when there are buildings up above at the surface
(at the surface the maximum effect is the power of one charge is timed
milliseconds apart - yet at the blast location the effect for the
tunneling is the sum of all blasts).
--------------------------------
As I understood it, the blasts are timed 0.1-0.5 Sec apart to let the
rock fragments exit the central opening at 40-70 m/Sec, and the
charges are large enough to fragment the rock but not so large they
pulverize and pack it against the opposite wall.

I'll tread carefully - especially as I see how far I have to go and
all the practical ahead of me - having just one 1.5m-deep blast-sized
hole in granite to my portfolio so far...

Yes - groups timed about 0.1-0.5sec apart - broadly representing
radial rings of charges.

However, in those rings there will be charges on the same "timing" and
if you need to avoid the crockery on the mantlepieces in houses above
bouncing you do have to have a subsequence milliseconds apart.

I am told that in Camborne/Pool/Redruth in the mining times up 'til
the 1990's, even though the workings were by then hundreds of metres
deep crockery rattling was just the familiar thing...
Thousands worked in mining and many times that worked in something
related to or supporting by mining and that was life there.
The blasts were at an expected time, one infers from the following...
They blasted just after the end of the day-shift - all but the
blasters left, the charges were detonated and everyone left the mine
while the ventilation cleared the fumes. ie. by the arrival of the
night-shift of the trammers, who moved the ore to the shafts, where it
was finer-crushed and loaded into skips hoisted to the surface.


Digressing into other detail:

I need to check this, but I think the stopers wrote on the "cousin
jack chutes" the number of wagons-full they wanted taking away from
under the working ends of the stopes, so that just the right amount of
"head-height" room was left for them to continue next day shift.
Given the blasted mineral takes up more volume than it occupied as
solid mineral forming the lode - hence needing to create space to
continue. Then the trammers could make up a full load in their train
with any amount from the "cousin jack chutes" back where the stope was
already cleared to full height below the next higher level. I think
that nightly how-many-wagons is the writing you see on cousin jack
chutes see in video of abandoned-mine explorers.

I've got plenty more to find out about...

[Jim Wilkins]

Post by Richard Smith
"millisecond-timed detonators" set me going - idea that it is possible
to blast when there are buildings up above at the surface
(at the surface the maximum effect is the power of one charge is timed
milliseconds apart - yet at the blast location the effect for the
tunneling is the sum of all blasts).
--------------------------------
As I understood it, the blasts are timed 0.1-0.5 Sec apart to let the
rock fragments exit the central opening at 40-70 m/Sec, and the
charges are large enough to fragment the rock but not so large they
pulverize and pack it against the opposite wall.

I'll tread carefully - especially as I see how far I have to go and
all the practical ahead of me - having just one 1.5m-deep blast-sized
hole in granite to my portfolio so far...

Yes - groups timed about 0.1-0.5sec apart - broadly representing
radial rings of charges.

However, in those rings there will be charges on the same "timing" and
if you need to avoid the crockery on the mantlepieces in houses above
bouncing you do have to have a subsequence milliseconds apart.

I am told that in Camborne/Pool/Redruth in the mining times up 'til
the 1990's, even though the workings were by then hundreds of metres
deep crockery rattling was just the familiar thing...
Thousands worked in mining and many times that worked in something
related to or supporting by mining and that was life there.
The blasts were at an expected time, one infers from the following...
They blasted just after the end of the day-shift - all but the
blasters left, the charges were detonated and everyone left the mine
while the ventilation cleared the fumes. ie. by the arrival of the
night-shift of the trammers, who moved the ore to the shafts, where it
was finer-crushed and loaded into skips hoisted to the surface.


Digressing into other detail:

I need to check this, but I think the stopers wrote on the "cousin
jack chutes" the number of wagons-full they wanted taking away from
under the working ends of the stopes, so that just the right amount of
"head-height" room was left for them to continue next day shift.
Given the blasted mineral takes up more volume than it occupied as
solid mineral forming the lode - hence needing to create space to
continue. Then the trammers could make up a full load in their train
with any amount from the "cousin jack chutes" back where the stope was
already cleared to full height below the next higher level. I think
that nightly how-many-wagons is the writing you see on cousin jack
chutes see in video of abandoned-mine explorers.

I've got plenty more to find out about...

----------------------------
You've gone far past welding.

A few years back there was some granite blasting within about 50m of my
house. They planted a seismograph next to the foundation to record the shock
intensity and fired much smaller shots than later and further away. That was
my only exposure to blasting practice. I caught most of the shots on video
just in case.

There was no central hole and they fired all the charges simultaneously as
far as I could tell. The blasts left deep pits filled with fairly large
boulders under the blasting mats, which didn't move much. After they left a
neighbor collected all the scrap metal and gave me a 3" drill bit with round
black (carbide?) buttons. The granite here is somewhat fractured and
contains many finer grained dikes.
https://en.wikipedia.org/wiki/New_England_hotspot

[Snag]

Post by Richard Smith

Post by Richard Smith
"millisecond-timed detonators" set me going - idea that it is possible
to blast when there are buildings up above at the surface
(at the surface the maximum effect is the power of one charge is timed
milliseconds apart - yet at the blast location the effect for the
tunneling is the sum of all blasts).
--------------------------------
As I understood it, the blasts are timed 0.1-0.5 Sec apart to let the
rock fragments exit the central opening at 40-70 m/Sec, and the
charges are large enough to fragment the rock but not so large they
pulverize and pack it against the opposite wall.

I'll tread carefully - especially as I see how far I have to go and
all the practical ahead of me - having just one 1.5m-deep blast-sized
hole in granite to my portfolio so far...
Yes - groups timed about 0.1-0.5sec apart - broadly representing
radial rings of charges.
However, in those rings there will be charges on the same "timing" and
if you need to avoid the crockery on the mantlepieces in houses above
bouncing you do have to have a subsequence milliseconds apart.
I am told that in Camborne/Pool/Redruth in the mining times up 'til
the 1990's, even though the workings were by then hundreds of metres
deep crockery rattling was just the familiar thing...
Thousands worked in mining and many times that worked in something
related to or supporting by mining and that was life there.
The blasts were at an expected time, one infers from the following...
They blasted just after the end of the day-shift - all but the
blasters left, the charges were detonated and everyone left the mine
while the ventilation cleared the fumes.  ie. by the arrival of the
night-shift of the trammers, who moved the ore to the shafts, where it
was finer-crushed and loaded into skips hoisted to the surface.
I need to check this, but I think the stopers wrote on the "cousin
jack chutes" the number of wagons-full they wanted taking away from
under the working ends of the stopes, so that just the right amount of
"head-height" room was left for them to continue next day shift.
Given the blasted mineral takes up more volume than it occupied as
solid mineral forming the lode - hence needing to create space to
continue.  Then the trammers could make up a full load in their train
with any amount from the "cousin jack chutes" back where the stope was
already cleared to full height below the next higher level.  I think
that nightly how-many-wagons is the writing you see on cousin jack
chutes see in video of abandoned-mine explorers.
I've got plenty more to find out about...
----------------------------
You've gone far past welding.
A few years back there was some granite blasting within about 50m of my
house. They planted a seismograph next to the foundation to record the
shock intensity and fired much smaller shots than later and further
away. That was my only exposure to blasting practice. I caught most of
the shots on video just in case.
There was no central hole and they fired all the charges simultaneously
as far as I could tell. The blasts left deep pits filled with fairly
large boulders under the blasting mats, which didn't move much. After
they left a neighbor collected all the scrap metal and gave me a 3"
drill bit with round black (carbide?) buttons. The granite here is
somewhat fractured and contains many finer grained dikes.
https://en.wikipedia.org/wiki/New_England_hotspot

I've seen explosives in use twice as an adolescent/teen . A guy was
using half-sticks of dynamite to bust up the foundation wall of an old
electric train station across the road from my childhood home . He would
park a front loader in front of each charge to catch any debris from
coming across the street towards the houses . The other time U&I Sugar
blasted a large limestone* formation up on the mountainside above town .
A large chunk of hillside jumped , and a few seconds later the shock
wave hit . We were leaning against the side of a house , felt the whole
house move .
* The limestone was processed into lime , used in the beet sugar
refining process .

[Richard Smith]

Thanks Jim, Snag. Adds to dimensions to understandings

[Jim Wilkins]

"Richard Smith" wrote in message news:***@void.com...

I am told that in Camborne/Pool/Redruth in the mining times up 'til
the 1990's, even though the workings were by then hundreds of metres
deep crockery rattling was just the familiar thing...
-----------------------------
This is perhaps too technical,
https://wiki.seg.org/wiki/Seismic_attenuation
but it contains this:
"Completely dry rocks display negligible attenuation."
meaning the energy loss from blast to house may be only the geometric 1/r^2,
by the inverse square law.

[Peter Fairbrother]

On 06/01/2024 21:17, Richard Smith wrote:
[...]

Post by Richard Smith
I was in a pub in Camborne with a lot of ex (and some current) tin
miners. Who were explaining thing like "You just stick a stick of
dynamite to it with a lump of clay and it does a job" and "No, we
couldn't use gelignite in South Crofty - too hot - the rock was at
about 80degrees - it would have gone off by itself before we finished
loading it" (that would be an "ooops") - and the sort of things kindly
Cornish ex-miners will explain over a few pints of beer.

Talking of small diameter brisant explosives for small-scale mining, how
about PETN detcord?

While usually loaded at 10 g/m for transmitting trunkline shocks and
directly initiating the more sensitive charges, it is also available in
up to 100 g/m loading, which is about 1/2" diameter, and possibly more.
It can be used up to 70C plus - one manufacturer says 107C is okay.

Not going to give you a huge face loading, but you could use fairly
close-spaced 1/2" holes?

Just an idea, I have no practical experience of this, but sometimes you
see detcord advertised for "pre-splitting", whatever that means.

Don't know about cost either, but I think a 50m roll of 100 or 150 g/m
should be a few £100's - and will last a long time. And it can be
detonated directly by standard 10g/m detcord, simple and providing a
saving on detonators, though you may need delays.



You didn't say whether the tunnel is through soft rock or granite?


Peter Fairbrother

[Richard Smith]

Post by Peter Fairbrother
[...]

Post by Richard Smith
I was in a pub in Camborne with a lot of ex (and some current) tin
miners. Who were explaining thing like "You just stick a stick of
dynamite to it with a lump of clay and it does a job" and "No, we
couldn't use gelignite in South Crofty - too hot - the rock was at
about 80degrees - it would have gone off by itself before we finished
loading it" (that would be an "ooops") - and the sort of things kindly
Cornish ex-miners will explain over a few pints of beer.

Talking of small diameter brisant explosives for small-scale mining,
how about PETN detcord?
While usually loaded at 10 g/m for transmitting trunkline shocks and
directly initiating the more sensitive charges, it is also available
in up to 100 g/m loading, which is about 1/2" diameter, and possibly
more. It can be used up to 70C plus - one manufacturer says 107C is
okay.
Not going to give you a huge face loading, but you could use fairly
close-spaced 1/2" holes?
Just an idea, I have no practical experience of this, but sometimes
you see detcord advertised for "pre-splitting", whatever that means.
Don't know about cost either, but I think a 50m roll of 100 or 150 g/m
should be a few £100's - and will last a long time. And it can be
detonated directly by standard 10g/m detcord, simple and providing a
saving on detonators, though you may need delays.
You didn't say whether the tunnel is through soft rock or granite?
Peter Fairbrother

Is all granite.
No killas (Cornish name for metamorphised sedimentary rock).
Up on top of Carn Brea, hence entirely granite.

What the granite looks like can be seen in my webpage on
boulder-splitting
http://www.weldsmith.co.uk/tech/minerals/240314_rocksplit/240314_rocksplit_drill_feathers.html
The split sections...

I have seen vids for using these about 1/4inch cartridges to split rock
in USA.
Apparently won't do much if not confined, so have dispensation to be
purchased without presenting explosives licence.

Thanks for detcord idea.
You couldn't drill deeply at 1/2inch (clearance at 14mm)...
At the 32mm of traditional Cornish drilling, could get 2m to 3m (?) - (I
managed 1.5m in a few minutes).

Ah - I see - way to cheaply practice - do it in miniature - make little
cubby-holes for storing tools in in the side of passageways, etc.

My instinct says one problem - with 14mm drill at longer lengths you can
get, could not get water to flow down flutes to where cutting happening.
Turn drillings into a harmless slurry, but also keep the drilling-tip
cool doing a lot of work in this hard granite.
You will be knowing - the drill-bits used in the likes of the Cornish
Holman rock-drill and the American Gardner rock-drill (?) have a hole
down the middle for the continuous supply of water which the rock-drill
supplies.


Rich S

[Jim Wilkins]

"Richard Smith" wrote in message news:***@void.com...

What the granite looks like can be seen in my webpage on
boulder-splitting
http://www.weldsmith.co.uk/tech/minerals/240314_rocksplit/240314_rocksplit_drill_feathers.html
The split sections...

--------------------------------

Congratulations on your successful innovation that leaps a major hurdle.

When the corded hammer drill proved useless on granite I was lucky enough to
be given the big Makita (to fix) which drills 1/2" (13mm) holes into granite
adequately, and my jobs are close enough to the house to not need cordless
tools for the harder slogging in granite or 1" holes in oak.

I didn't know there was an application for a close quarters masonry drill.
I've used right angle drills only between house studs and under cars. The
contractor bought the Makita and a long 1-1/4" bit for plumbing and wiring
holes through concrete foundations. It takes spline drive bits which are
becoming rare, he replaced it with SDS Plus.
SDS = Steck-Dreh-Sitz, Insert-Turn-Seat.

[Richard Smith]

Thanks for encouragement.
My instinct is "never say it's until until it's done".
It's done. But it took some drive to get there.

[Peter Fairbrother]

On 24/03/2024 08:29, Richard Smith wrote:
[..]

Post by Richard Smith
Thanks for detcord idea.
You couldn't drill deeply at 1/2inch (clearance at 14mm)...
At the 32mm of traditional Cornish drilling, could get 2m to 3m (?) - (I
managed 1.5m in a few minutes).
Ah - I see - way to cheaply practice - do it in miniature - make little
cubby-holes for storing tools in in the side of passageways, etc.

PLEASE NOTE: I AM NOT AN EXPERT ON ROCK BLASTING

I was thinking more like, for a person width and height tunnel, say 3x9
shots at 8" spacing, with 50cm deep holes with 40cm of 100g/m high
loading detcord and 10cm stemming, connected by some low loading detcord.

Or possibly better, 15cm hldc, 10cm stemming, 15cm hldc, 10cm stemming,
with a low loading detcord going past both hldc charges. Or even
8-8-8-8-8-10, if you can bear to do that.

Either no delays and only one detonator, or say divide it into four
sections and use maybe three delay detonators.

That kind of cautious blasting, if it would work on the rock (it should
be about right, but no guarantees), should not make too big a
disturbance with aboveground at 20m. It might even be unnoticeable, even
though it's a kilo of PETN.

For a hobby program.

As the tunnel isn't going to be very long - how long? one, a few, ten
meters? - it shouldn't take too many shots.

Not that cheaply though; but a 50m roll of high loading detcord will get
you maybe 5 to 8 shots. The low loading detcord will probably come in a
much longer roll, and cost a little less.

Say £100 per shot, or a little more at 60cm of tunnel per shot.

PLEASE NOTE: I AM NOT AN EXPERT ON ROCK BLASTING

Post by Richard Smith
My instinct says one problem - with 14mm drill at longer lengths you can
get, could not get water to flow down flutes to where cutting happening.
Turn drillings into a harmless slurry, but also keep the drilling-tip
cool doing a lot of work in this hard granite.
You will be knowing - the drill-bits used in the likes of the Cornish
Holman rock-drill and the American Gardner rock-drill (?) have a hole
down the middle for the continuous supply of water which the rock-drill
supplies.

I didn't know that, specifically, though I do use through-fluid cooled
drill bits from time to time. I don't know much about mining.

But I was only thinking of half a meter deep. That will still give you
some rock to cart away between shots.

And if you can drill some larger diameter unfilled holes as well, so
much the better. If the rock is only a few meters thick, you might drill
through on the first try with a larger longer drill.



Peter Fairbrother

[Richard Smith]

I like your thinking Peter.
How to practice at manageable cost.
That's the crucial point.
Don't know what would happen.
Would be interesting to find-out.

[Jim Wilkins]

Could you blast with black powder as a historical re-enactment without
official hindrance?

[Snag]

Post by Jim Wilkins
Could you blast with black powder as a historical re-enactment without
official hindrance?

Don't know what the laws are Over There , but here in Arkansas ... I
have several part-containers of Pyrodex that I've picked up here and
there . Mostly yard sale stuff . My neighbor has some stumps . One in
particular is right in the middle of where he wants his driveway . The
plan is to drill it 1 1/2 inches and about 12-14" deep . Load about 2
ounces of Pyrodex R-S with a small charge of BP on top to ensure
ignition and pack the hole with clay . We'll use cannon fuse to initiate
the festivities . The objective is to split the stump into pieces he can
drag out with his front-loader .

[Bob La Londe]

Post by Jim Wilkins
Could you blast with black powder as a historical re-enactment without
official hindrance?

  Don't know what the laws are Over There , but here in Arkansas ... I
have several part-containers of Pyrodex that I've picked up here and
there . Mostly yard sale stuff . My neighbor has some stumps . One in
particular is right in the middle of where he wants his driveway . The
plan is to drill it 1 1/2 inches and about 12-14" deep . Load about 2
ounces of Pyrodex R-S with a small charge of BP on top to ensure
ignition and pack the hole with clay . We'll use cannon fuse to initiate
the festivities . The objective is to split the stump into pieces he can
drag out with his front-loader .

I'd like to hear how that goes. I may or may not have some knowledge of
BP being easy to make firecrackers with, and Pyrodex in the same
packaging becoming spinners or rockets instead of going pop.

[Snag]

Post by Jim Wilkins
Could you blast with black powder as a historical re-enactment
without official hindrance?

   Don't know what the laws are Over There , but here in Arkansas ...
I have several part-containers of Pyrodex that I've picked up here and
there . Mostly yard sale stuff . My neighbor has some stumps . One in
particular is right in the middle of where he wants his driveway . The
plan is to drill it 1 1/2 inches and about 12-14" deep . Load about 2
ounces of Pyrodex R-S with a small charge of BP on top to ensure
ignition and pack the hole with clay . We'll use cannon fuse to
initiate the festivities . The objective is to split the stump into
pieces he can drag out with his front-loader .

I'd like to hear how that goes.  I may or may not have some knowledge of
BP being easy to make firecrackers with, and Pyrodex in the same
packaging becoming spinners or rockets instead of going pop.

It's all about confinement . Lots of difference between a few layers
of paper and about 8"-10" of solid wood .

[pyotr filipivich]

Post by Snag

I'd like to hear how that goes.  I may or may not have some knowledge of
BP being easy to make firecrackers with, and Pyrodex in the same
packaging becoming spinners or rockets instead of going pop.

It's all about confinement . Lots of difference between a few layers
of paper and about 8"-10" of solid wood .

Tamp it well, or you're likely to have a rocket launcher / cannon.

We once made a "signal gun" for the 4th out of a bored out chunk
of maple.

[Snag]

Post by pyotr filipivich

Post by Snag

I'd like to hear how that goes.  I may or may not have some knowledge of
BP being easy to make firecrackers with, and Pyrodex in the same
packaging becoming spinners or rockets instead of going pop.

It's all about confinement . Lots of difference between a few layers
of paper and about 8"-10" of solid wood .

Tamp it well, or you're likely to have a rocket launcher / cannon.
We once made a "signal gun" for the 4th out of a bored out chunk
of maple.

We are blessed here with an abundance of clay ... I was talking with
a guy that has some experience with this and he suggested clay as an
ideal tamping medium . There's a large flat rock right next to the stump
that I might lay on top too .

[Richard Smith]

Post by Jim Wilkins
Could you blast with black powder as a historical re-enactment without
official hindrance?

Black powder can be had - you are allowed to own muzzle-loaders here in
the UK. With licencing yes; but "doable".

Whether a larger amount in the kg's could be had that way...

Black powder is used by stone masons because it will split rock without
any shattering.
It is on sale in bulk - but sure you would need a licence for that.

[Snag]

Post by Richard Smith
Sorry - that's "ANFO", as you point out.
"Little puffs of dust" - apparently (my local connections) that's
exactly what you should get.
Exasperated comment that many Company "buy our wonderful product"
videos have plumes of ejected material because it looks good - but is
technically wrong and misleading.
Urea - I was thinking ammonium nitrate?
Apparently mining companies using tonnes of the stuff do their own
mixing.
However there are the made-up "prills" - seen as pink "bits" - for
more modest users it seems.

Yup , ammonium nitrate as the oxidizer , fuel oil as the fuel . I had
a couple of years back in the late 70's working with some very good
engineers of various disciplines at Thiokol Chemical's Wasatch Division
. A couple of things I learned about ANFO is that the AN will absorb
just exactly the right amount of FO to be perfectly oxygen balanced and
that you've got to hit it pretty hard to make it detonate .

Post by Richard Smith
Shaped charges - not in this application?

Shaped charges are easy and very effective . Stick a funnel in the
end of a tube with the pointed end in the tube . Fill the tube with
explosive and initiate from the opposite end from the funnel . Crude and
there's a lot more science involved to get the exact results you want
but you just built a shaped charge . Probably not effective for the type
of tunneling you're doing .

Post by Richard Smith
The pattern the holes are drilled is doing all the "focusing" to get
optimal result. Cylindrical holes metres long filled with blasting
agent.
The thrill about using the Holman rock-drill - the "Holman Silver 3
Airleg" - N.Am. = "jackleg"
which I didn't mention (?) because I could find no good photos and
didn't take a camera with me down the mine because didn't know I
would be in the granite section (dry - killas section is like being
in a shower at times) and having my first go with a rock-drill -
anyway I ran a hole the size of a stick of gelignite (about 35mm?)
1~1/2metres into the hard granite wall of one of the levels in
minutes -- that was promising with the ex-miner stepping-away after
about a minute, satisfied to leave me running the hole -- the
drilling being parallel in the horizontal and vertical planes to
the central "reference" hole
lead to this next thought - the purpose of hole-drilling which can now
be done is blasting. And there is hope of finding a lode to the side
of the existing workings. Clear so cannot disturb historical workings.
The folk here damn' well know about all this stuff, but looking to
other views. Other cultures of mining. Looking to learn.
I have seen videos of blasting "panels" of rock in quarries.
This was done in quarries near where I grew-up.
When I was ill off school at home during the day, you would hear the
siren going for a couple of minutes, then a "bang". From the
limestone area a few miles away...
As I mentioned, the overall pattern of this blasting here in mining is
radial, about the lengthwise centre of the level being extended (if I
understand rightly - mainly from Geevor Mine museum).

Happy blasting ! You mentioned at some point in this discussion
"small puffs" coming from the blasting holes . Actually those holes
should be packed with material to confine the blast . Anything being
ejected into open air is wasted energy that was not used for the primary
task of (in this case) shattering rock . (I also studied Dad's copy of
the DuPont Blaster's Handbook whenever I could sneak a peek.)

[Bob La Londe]

Post by Richard Smith
Sorry - that's "ANFO", as you point out.
"Little puffs of dust" - apparently (my local connections) that's
exactly what you should get.
Exasperated comment that many Company "buy our wonderful product"
videos have plumes of ejected material because it looks good - but is
technically wrong and misleading.
Urea - I was thinking ammonium nitrate?
Apparently mining companies using tonnes of the stuff do their own
mixing.
However there are the made-up "prills" - seen as pink "bits" - for
more modest users it seems.

  Yup , ammonium nitrate as the oxidizer , fuel oil as the fuel . I had
a couple of years back in the late 70's working with some very good
engineers of various disciplines at Thiokol Chemical's Wasatch Division
. A couple of things I learned about ANFO is that the AN will absorb
just exactly the right amount of FO to be perfectly oxygen balanced and
that you've got to hit it pretty hard to make it detonate .

Post by Richard Smith
Shaped charges - not in this application?

  Shaped charges are easy and very effective . Stick a funnel in the
end of a tube with the pointed end in the tube . Fill the tube with
explosive and initiate from the opposite end from the funnel . Crude and
there's a lot more science involved to get the exact results you want
but you just built a shaped charge . Probably not effective for the type
of tunneling you're doing .

Post by Richard Smith
The pattern the holes are drilled is doing all the "focusing" to get
optimal result.  Cylindrical holes metres long filled with blasting
agent.
The thrill about using the Holman rock-drill - the "Holman Silver 3
Airleg" - N.Am. = "jackleg"
    which I didn't mention (?) because I could find no good photos and
    didn't take a camera with me down the mine because didn't know I
    would be in the granite section (dry - killas section is like being
    in a shower at times) and having my first go with a rock-drill -
    anyway I ran a hole the size of a stick of gelignite (about 35mm?)
    1~1/2metres into the hard granite wall of one of the levels in
    minutes -- that was promising with the ex-miner stepping-away after
    about a minute, satisfied to leave me running the hole -- the
    drilling being parallel in the horizontal and vertical planes to
    the central "reference" hole
lead to this next thought - the purpose of hole-drilling which can now
be done is blasting.  And there is hope of finding a lode to the side
of the existing workings.  Clear so cannot disturb historical workings.
The folk here damn' well know about all this stuff, but looking to
other views.  Other cultures of mining.  Looking to learn.
I have seen videos of blasting "panels" of rock in quarries.
This was done in quarries near where I grew-up.
When I was ill off school at home during the day, you would hear the
siren going for a couple of minutes, then a "bang".  From the
limestone area a few miles away...
As I mentioned, the overall pattern of this blasting here in mining is
radial, about the lengthwise centre of the level being extended (if I
understand rightly - mainly from Geevor Mine museum).

  Happy blasting ! You mentioned at some point in this discussion
"small puffs" coming from the blasting holes . Actually those holes
should be packed with material to confine the blast . Anything being
ejected into open air is wasted energy that was not used for the primary
task of (in this case) shattering rock . (I also studied Dad's copy of
the DuPont Blaster's Handbook whenever I could sneak a peek.)

Going back before my time farmers used to keep dynamite for blasting out
trees. My mom told me her dad blasted out trees on their farm because
it would pop giant stumps right out of the ground and it left the earth
nice and soft for cultivation.

My dad tells a story about when he was a kid. I might have retold this
one here before. Near where he grew up he and his buddies used to play
and swim in French Creek. They had a spot they call their swimming
hole. It was the biggest pool on the creek, but there was a stump right
in the middle of it. The bunch of them griped about it for a while, and
one of the kids mentioned his dad had a case of dynamite in the garage.
It took them a while to work up their nerve, but they planned one day to
meet up at the creek, dig in under that stump, and blast it out. As my
dad and his buddy Tom where headed to the creek with tools to meet up
with the other guys the kid who had the dynamite came running back up
over that hill yelling, "Get down its about to blow!"

(My dad tells the story better.)

They all hit the ground and felt the earth shake from the explosion.
They saw the stump flying through the air back towards the main rode
where it landed in the driveway of the kid who brought the dynamite. It
just barely missed his dad's car as he was pulling in from the road.

They got to talk to him for a minute to ask how much he had used before
they heard his dad yelling for him.

He had debated about how much to use. He didn't want to go to light and
have to blast again. He knew after the first blast he'd have to clear
out because people might come to see what was going on if only to help a
neighbor drag out a stump in a field. He kept adding more, and before
he knew it he had packed the whole case under the stump.

My dad said after that they didn't have a swimming hole in the creek
anymore. They had a swimming pool, but they didn't see the kid with the
dynamite for the rest of the summer.

[Richard Smith]

Kids... We've all done it...

[Bob La Londe]

Post by Richard Smith

Post by Bob La Londe

Post by Richard Smith
Anyone here know about blasting person-height&width tunnels in hard
rock?
I have some contacts here (UK), but broadening the casting around for
information. Maybe bringing in North American perspective.
Especially noting how much I have gained here from previous ask about
mine haulage-shafts and skips.
New to me. If I'm pointed in the right direction and told the real
deal(s) to look out for, I can do a lot of my own reading.
Some of the rock here is "killas" - a heated "metamorphosed"
sedimentary rock which is quite brittle. Usually associated with
"wet" mines.
Then there is hard granite. Very hard. A 4-carbide-teeth drill bit
cannot touch some when driven by a rock-drill which can go 1~1/2metres
in minutes with a simple chisel-edged carbide-tipped drill bit. Mines
in that can go a mile out under the sea and be dry.
As best I can explain from what I have seen; being a metallurgist and
welder.
There's something which would be very useful here making everything
possible, so it seems.
Something about electronically timed detonators which can serially
detonate "go off at the same time" charges a few microseconds apart,
which is apparently enough that at the surface only the effect of one
charge is felt.
So pointers on that would be appreciated.
Blasting mine tunnels is done radially here I gather from what I have
seen explained at mining museums - blast from the middle outwards,
sending the fractured rock towards the middle (heard of the central
hole being "reamed" - no charge in it obviously - provides the first
void to collapse the first ring of rock into).
Historically gelignite but noted that "ampho" is usually cheaper now.
Another reason for asking for a North American viewpoint is that folk
are much less restricted there - and therefore you get a lot of very
practically experienced folk. eg. when in Texas my host took me to
the range every morning with two holdalls full of hardware - learned a
lot quickly.
Everyone has to be very stern and restricted here trying to appease
the powers-that-be that everyone is very serious and narrow focussed -
no "plinking" or anything like that - and carries over into methods to
make lighter of rearranging rock.
Searching the Web on my own, I wouldn't know when I am "finding gold"
and when it's rubbish.
If you want to personal-message me, go to my website "weldsmith.co.uk"
and use the "Contact me" form and we can pick up on a private email
chat if you prefer that.
Thanks in advance,
Rich Smith

No. Not one bit. I suspect small shaped charges might be the ticket
if blasting were the only option, but the little bit of blasting I've
been around used "cruder" explosives due to cost. Things like bags or
urea dropped down a hole with diesel and blasting caps. Somewhere
around my dad's house is a VHS tape I recorded out in the desert from
when Western rock removed almost the entire south face of Aztec hill.
I don't recall how much urea they said they used any more, but it was
a lot. Not much of a show. Three little puffs of dust out the bore
holes, a hint of movement, and then 30-45 minutes waiting for the dust
to clear even though it was a windy day.
They'd spent weeks talking up their big blast in local stores and bars...
I might see if my dad still has that tape. It might be fun to
digitize and put on YouTube....
350LB of Urea & Diesel GOES POP!
--
Bob La Londe
CNC Molds N Stuff
--
This email has been checked for viruses by AVG antivirus software.
www.avg.com

Sorry - that's "ANFO", as you point out.
"Little puffs of dust" - apparently (my local connections) that's
exactly what you should get.
Exasperated comment that many Company "buy our wonderful product"
videos have plumes of ejected material because it looks good - but is
technically wrong and misleading.
Urea - I was thinking ammonium nitrate?
Apparently mining companies using tonnes of the stuff do their own
mixing.
However there are the made-up "prills" - seen as pink "bits" - for
more modest users it seems.
Shaped charges - not in this application?
The pattern the holes are drilled is doing all the "focusing" to get
optimal result. Cylindrical holes metres long filled with blasting
agent.
The thrill about using the Holman rock-drill - the "Holman Silver 3
Airleg" - N.Am. = "jackleg"
which I didn't mention (?) because I could find no good photos and
didn't take a camera with me down the mine because didn't know I
would be in the granite section (dry - killas section is like being
in a shower at times) and having my first go with a rock-drill -
anyway I ran a hole the size of a stick of gelignite (about 35mm?)
1~1/2metres into the hard granite wall of one of the levels in
minutes -- that was promising with the ex-miner stepping-away after
about a minute, satisfied to leave me running the hole -- the
drilling being parallel in the horizontal and vertical planes to
the central "reference" hole
lead to this next thought - the purpose of hole-drilling which can now
be done is blasting. And there is hope of finding a lode to the side
of the existing workings. Clear so cannot disturb historical workings.
The folk here damn' well know about all this stuff, but looking to
other views. Other cultures of mining. Looking to learn.
I have seen videos of blasting "panels" of rock in quarries.
This was done in quarries near where I grew-up.
When I was ill off school at home during the day, you would hear the
siren going for a couple of minutes, then a "bang". From the
limestone area a few miles away...
As I mentioned, the overall pattern of this blasting here in mining is
radial, about the lengthwise centre of the level being extended (if I
understand rightly - mainly from Geevor Mine museum).

I think urea is the same as ammonium nitrate. A lot of companies mix it
up on site because of transport regulations. In the states many
explosive components require little or no licensing to transport. They
would still need licensing for the blasting caps.

There is a watch on buying quantities of ammonium nitrate since the
Oklahoma Federal building truck bombing, but its still no more difficult
to transport than any other relatively safe farm chemical.

Here is an interesting aside. I can legally make a few explosives on my
own property for use on site for entertainment purposes only, but if I
put them in a strong container with a fuse or igniter they are a
destructive device which is required to be registered individually. I
can't legally make a pipe bomb, but I can legally make black powder (and
a few other things) as long as I don't transport it on public roads or
government regulated transport. (planes, trains, etc.) Now if I buy
that black powder at a store I can carry it around in my truck all day
long if I want to. LOL.

Being lazy, and wanting to take my Pennsylvania rifle to where the deer
are I buy my black powder (substitute) from a store.

[Richard Smith]

black powder...

I have fired some black-powder firers in the UK. Replicas.

I was surprised to see black powder listed in current stock with a
wholesaler when looking yesterday for timers, etc.
What??! :-)
Amazed, I looked with curiousity - and find it has a niche.
Masoned stone. Quarries for, I assume (?) Avoid shattering the rock
you want to extract in big "as it's been for hundreds of millions of
years" blocks.
Well, well, well - always a surprise.

[David Brooks]

Post by Richard Smith

Post by Richard Smith
Anyone here know about blasting person-height&width tunnels in hard
rock?
I have some contacts here (UK), but broadening the casting around for
information.  Maybe bringing in North American perspective.
Especially noting how much I have gained here from previous ask about
mine haulage-shafts and skips.
New to me.  If I'm pointed in the right direction and told the real
deal(s) to look out for, I can do a lot of my own reading.
Some of the rock here is "killas" - a heated "metamorphosed"
sedimentary rock which is quite brittle.  Usually associated with
"wet" mines.
Then there is hard granite.  Very hard.  A 4-carbide-teeth drill bit
cannot touch some when driven by a rock-drill which can go 1~1/2metres
in minutes with a simple chisel-edged carbide-tipped drill bit.  Mines
in that can go a mile out under the sea and be dry.
As best I can explain from what I have seen; being a metallurgist and
welder.
There's something which would be very useful here making everything
possible, so it seems.
Something about electronically timed detonators which can serially
detonate "go off at the same time" charges a few microseconds apart,
which is apparently enough that at the surface only the effect of one
charge is felt.
So pointers on that would be appreciated.
Blasting mine tunnels is done radially here I gather from what I have
seen explained at mining museums - blast from the middle outwards,
sending the fractured rock towards the middle (heard of the central
hole being "reamed" - no charge in it obviously - provides the first
void to collapse the first ring of rock into).
Historically gelignite but noted that "ampho" is usually cheaper now.
Another reason for asking for a North American viewpoint is that folk
are much less restricted there - and therefore you get a lot of very
practically experienced folk.  eg. when in Texas my host took me to
the range every morning with two holdalls full of hardware - learned a
lot quickly.
Everyone has to be very stern and restricted here trying to appease
the powers-that-be that everyone is very serious and narrow focussed -
no "plinking" or anything like that - and carries over into methods to
make lighter of rearranging rock.
Searching the Web on my own, I wouldn't know when I am "finding gold"
and when it's rubbish.
If you want to personal-message me, go to my website "weldsmith.co.uk"
and use the "Contact me" form and we can pick up on a private email
chat if you prefer that.
Thanks in advance,
Rich Smith

No.  Not one bit.  I suspect small shaped charges might be the ticket
if blasting were the only option, but the little bit of blasting I've
been around used "cruder" explosives due to cost.  Things like bags or
urea dropped down a hole with diesel and blasting caps.  Somewhere
around my dad's house is a VHS tape I recorded out in the desert from
when Western rock removed almost the entire south face of Aztec hill.
I don't recall how much urea they said they used any more, but it was
a lot.  Not much of a show.  Three little puffs of dust out the bore
holes, a hint of movement, and then 30-45 minutes waiting for the dust
to clear even though it was a windy day.
They'd spent weeks talking up their big blast in local stores and bars...
I might see if my dad still has that tape.  It might be fun to
digitize and put on YouTube....
350LB of Urea & Diesel GOES POP!
--
Bob La Londe
CNC Molds N Stuff
--
This email has been checked for viruses by AVG antivirus software.
www.avg.com

Sorry - that's "ANFO", as you point out.
"Little puffs of dust" - apparently (my local connections) that's
exactly what you should get.
Exasperated comment that many Company "buy our wonderful product"
videos have plumes of ejected material because it looks good - but is
technically wrong and misleading.
Urea - I was thinking ammonium nitrate?
Apparently mining companies using tonnes of the stuff do their own
mixing.
However there are the made-up "prills" - seen as pink "bits" - for
more modest users it seems.
Shaped charges - not in this application?
The pattern the holes are drilled is doing all the "focusing" to get
optimal result.  Cylindrical holes metres long filled with blasting
agent.
The thrill about using the Holman rock-drill - the "Holman Silver 3
Airleg" - N.Am. = "jackleg"
    which I didn't mention (?) because I could find no good photos and
    didn't take a camera with me down the mine because didn't know I
    would be in the granite section (dry - killas section is like being
    in a shower at times) and having my first go with a rock-drill -
    anyway I ran a hole the size of a stick of gelignite (about 35mm?)
    1~1/2metres into the hard granite wall of one of the levels in
    minutes -- that was promising with the ex-miner stepping-away after
    about a minute, satisfied to leave me running the hole -- the
    drilling being parallel in the horizontal and vertical planes to
    the central "reference" hole
lead to this next thought - the purpose of hole-drilling which can now
be done is blasting.  And there is hope of finding a lode to the side
of the existing workings.  Clear so cannot disturb historical workings.
The folk here damn' well know about all this stuff, but looking to
other views.  Other cultures of mining.  Looking to learn.
I have seen videos of blasting "panels" of rock in quarries.
This was done in quarries near where I grew-up.
When I was ill off school at home during the day, you would hear the
siren going for a couple of minutes, then a "bang".  From the
limestone area a few miles away...
As I mentioned, the overall pattern of this blasting here in mining is
radial, about the lengthwise centre of the level being extended (if I
understand rightly - mainly from Geevor Mine museum).

I think urea is the same as ammonium nitrate.  A lot of companies mix it
up on site because of transport regulations.  In the states many
explosive components require little or no licensing to transport.  They
would still need licensing for the blasting caps.
There is a watch on buying quantities of ammonium nitrate since the
Oklahoma Federal building truck bombing, but its still no more difficult
to transport than any other relatively safe farm chemical.
Here is an interesting aside.  I can legally make a few explosives on my
own property for use on site for entertainment purposes only, but if I
put them in a strong container with a fuse or igniter they are a
destructive device which is required to be registered individually.  I
can't legally make a pipe bomb, but I can legally make black powder (and
a few other things) as long as I don't transport it on public roads or
government regulated transport.  (planes, trains, etc.)   Now if I buy
that black powder at a store I can carry it around in my truck all day
long if I want to.  LOL.
Being lazy, and wanting to take my Pennsylvania rifle to where the deer
are I buy my black powder (substitute) from a store.

Urea /= Ammonium Nitrate. See Wikipedia: AN is mixed with diesel to make
an explosive; urea is inert of itself, & must be reacted with nitric
acid to give urea nitrate, which is explosive (needing no oil).

As stated, large mining operations use ANFO (ammonium nitrate - fuel
oil) in ton lots. Here in Perth (Australia), we often follow a
"B-double" (semi-trailer with 2 trailers) with a big hazmat plate on the
back warning of ammonium nitrate. It's not unknown for these trucks to
be involved in an accident, & the whole lot goes bang. See
https://www.abc.net.au/news/2022-11-03/truck-explosion-wa-goldfields-mining-blasting-/101609164

The mines mix AN & fuel oil in what's basically a truck-cement mixer, &
pump it straight down the holes. The holes are wired together, with a
sub-second delay between each, so you get a ripple effect, rather than
one big bang.

[Richard Smith]

Post by Richard Smith
Anyone here know about blasting person-height&width tunnels in hard
rock?
I have some contacts here (UK), but broadening the casting around for
information.  Maybe bringing in North American perspective.
Especially noting how much I have gained here from previous ask about
mine haulage-shafts and skips.
New to me.  If I'm pointed in the right direction and told the real
deal(s) to look out for, I can do a lot of my own reading.
Some of the rock here is "killas" - a heated "metamorphosed"
sedimentary rock which is quite brittle.  Usually associated with
"wet" mines.
Then there is hard granite.  Very hard.  A 4-carbide-teeth drill bit
cannot touch some when driven by a rock-drill which can go 1~1/2metres
in minutes with a simple chisel-edged carbide-tipped drill bit.  Mines
in that can go a mile out under the sea and be dry.
As best I can explain from what I have seen; being a metallurgist and
welder.
There's something which would be very useful here making everything
possible, so it seems.
Something about electronically timed detonators which can serially
detonate "go off at the same time" charges a few microseconds apart,
which is apparently enough that at the surface only the effect of one
charge is felt.
So pointers on that would be appreciated.
Blasting mine tunnels is done radially here I gather from what I have
seen explained at mining museums - blast from the middle outwards,
sending the fractured rock towards the middle (heard of the central
hole being "reamed" - no charge in it obviously - provides the first
void to collapse the first ring of rock into).
Historically gelignite but noted that "ampho" is usually cheaper now.
Another reason for asking for a North American viewpoint is that folk
are much less restricted there - and therefore you get a lot of very

...
trucks to be involved in an accident, & the whole lot goes bang. See
https://www.abc.net.au/news/2022-11-03/truck-explosion-wa-goldfields-mining-blasting-/101609164
...

Job done well! :-)

[Richard Smith]

Post by David Brooks
The mines mix AN & fuel oil in what's basically a truck-cement mixer,
& pump it straight down the holes. The holes are wired together, with
a sub-second delay between each, so you get a ripple effect, rather
than one big bang.

With houses only a few 10's of metres overhead, might be looking for a
more sophisticated timing sequence than that.

Perth - sounds like the place to be a miner.
One tin mine is going to reopen here in Cornwall, UK.
Is South Crofty.
Being pumped. Over a year to go before down to the sump and can
tunnel deeper going for tin down there.

[Peter Fairbrother]

On 17/12/2023 23:24, Bob La Londe wrote:
[...]

Post by Bob La Londe
I think urea is the same as ammonium nitrate.

Urea itself is not explosive, and is seldom used in explosives, though
it is sometimes added in small proportions to ANFO to prevent noxious
gases when eg pyrite is present.

Urea nitrate is sometimes used in home made explosives, but it is not
used in any civil explosives I know of, or for blasting purposes -
that's mostly the province of ANFO and water gels, with gelignites and
dynamites occasionally used on smaller scales and for demolition work.

Water gels and emulsion explosives are typically mixed on-site from
ammonium nitrate solutions plus fuels. They are usually not
cap-sensitive, though cap-sensitive ones do exist, and need a booster
explosive charge to detonate. The non-cap-sensitive ones are easier to
transport.

ANFO is also often made on site. Ammonium nitrate prills come in two
types, in one the prills are carefully engineered so that they will
absorb exactly the right amount of fuel oil if they are to be used in
ANFO explosives, and in the other they are engineered so they won't
absorb fuel oil if the AN is to be used as fertiliser.


Sorry, I don't have any practical experience in blasting tunnels. You do
usually need higher velocity explosives like dynamite or gelignite for
hard rocks though.


Peter Fairbrother

[Richard Smith]

Post by Peter Fairbrother
[...]

Post by Bob La Londe
I think urea is the same as ammonium nitrate.

Urea itself is not explosive, and is seldom used in explosives, though
it is sometimes added in small proportions to ANFO to prevent noxious
gases when eg pyrite is present.
Urea nitrate is sometimes used in home made explosives, but it is not
used in any civil explosives I know of, or for blasting purposes -
that's mostly the province of ANFO and water gels, with gelignites and
dynamites occasionally used on smaller scales and for demolition work.
Water gels and emulsion explosives are typically mixed on-site from
ammonium nitrate solutions plus fuels. They are usually not
cap-sensitive, though cap-sensitive ones do exist, and need a booster
explosive charge to detonate. The non-cap-sensitive ones are easier to
transport.
ANFO is also often made on site. Ammonium nitrate prills come in two
types, in one the prills are carefully engineered so that they will
absorb exactly the right amount of fuel oil if they are to be used in
ANFO explosives, and in the other they are engineered so they won't
absorb fuel oil if the AN is to be used as fertiliser.
Sorry, I don't have any practical experience in blasting tunnels. You
do usually need higher velocity explosives like dynamite or gelignite
for hard rocks though.
Peter Fairbrother

Thanks for that.
Since I posted this question I have learned a lot.

The "traditional" blasting medium used in Cornwall was gelignite.
I've had comment that cost would make you have second thoughts about
doing that to conform with tradition.
Brings ANFO to the fore now.
I've read about "emulsion". Seems is "the business" when you have a
big tanker driving around pouring into many big blasting holes.
"per-unit" cost very favourable - but the costs of maintaining a
storage of "ANBI", pumps to safely handle ANBI, etc. - the set-up and
maintenance costs - might have you looking at ANFO (?)

I have a lot more learning to do.
Couple of articles recommended here which I am reading.
Wanted to post something along the lines of "Wow!" in that what was
unintelligible before now in the main makes sense.
Will continue to read and learn in other ways then report back.

The granite I met here is so hard that a powerful rock-drill
(percussion plus rotation) could not drill with a four-cutting-tips
cutter - had to revert back to a carbide-tipped chisel-edge drill.

Implies that need a goodly blasting medium.

Anyway, hopefully will be back here soon.

Rich S

[Jim Wilkins]

"Richard Smith" wrote in message news:***@void.com...

The granite I met here is so hard that a powerful rock-drill
(percussion plus rotation) could not drill with a four-cutting-tips
cutter - had to revert back to a carbide-tipped chisel-edge drill.

Implies that need a goodly blasting medium.

Anyway, hopefully will be back here soon.

Rich S
------------------------
With my drill NH granite cuts faster by starting with a 1/2" bit. "Fast" is
relative, at least I can see it move.

By Hiram Maxim's brother:
https://www.gutenberg.org/files/46039/46039-h/46039-h.htm

https://www.gutenberg.org/files/65791/65791-h/65791-h.htm

[Peter Fairbrother]

[...]

Post by Richard Smith

Post by Peter Fairbrother
Urea nitrate is sometimes used in home made explosives, but it is not
used in any civil explosives I know of, or for blasting purposes -
that's mostly the province of ANFO and water gels, with gelignites and
dynamites occasionally used on smaller scales and for demolition work.
Water gels and emulsion explosives are typically mixed on-site from
ammonium nitrate solutions plus fuels. They are usually not
cap-sensitive, though cap-sensitive ones do exist, and need a booster
explosive charge to detonate. The non-cap-sensitive ones are easier to
transport.
ANFO is also often made on site. Ammonium nitrate prills come in two
types, in one the prills are carefully engineered so that they will
absorb exactly the right amount of fuel oil if they are to be used in
ANFO explosives, and in the other they are engineered so they won't
absorb fuel oil if the AN is to be used as fertiliser.
Sorry, I don't have any practical experience in blasting tunnels. You
do usually need higher velocity explosives like dynamite or gelignite
for hard rocks though.
Peter Fairbrother

Thanks for that.
Since I posted this question I have learned a lot.
The "traditional" blasting medium used in Cornwall was gelignite.
I've had comment that cost would make you have second thoughts about
doing that to conform with tradition.

Yes, it is more expensive. As is NG-dynamite. However they are about
twice as powerful as ANFO, so you need less.

Post by Richard Smith
Brings ANFO to the fore now.
I've read about "emulsion". Seems is "the business" when you have a
big tanker driving around pouring into many big blasting holes.
"per-unit" cost very favourable - but the costs of maintaining a
storage of "ANBI", pumps to safely handle ANBI, etc. - the set-up and
maintenance costs - might have you looking at ANFO (?)

I'm unsure whether the AN used in ANFO is itself an ANBI - if AN is
prilled for explosives purposes it might well be. Or perhaps it is
controlled under one of the many AN control orders, which I have only a
passing familiarity with.


However there is another problem or three with ANFOs, AN water gels and
emulsions - they need bigger holes than NG-dynamites or gelignites, as
they will not explode properly when the diameter of the hole is small.

In practice, combined with the fact that they are only about half as
powerful, you end up using a lot more. Which means a lot more nasty
gases to get out of your tunnel.

Second, they really need boosters. There are cap-sensitive gels and
emulsions, but then you are getting into the same legal hassles as the
higher velocity explosives - plus you need different certificates and
licenses for the boosters. Some people use detcord as a booster, but the
same requirement for an explosives certificate etc applies (in the UK).

Third, and perhaps most important, especially when used for tunnels in
hard rock, they aren't really brisant enough to cope with hard granite.
The NG-based (or NC-based) high velocity explosives produce shock waves
which will fracture granite, but the lower velocity of detonation of the
AN-based explosives give more of a hard push than a breaking shock.

Post by Richard Smith
The granite I met here is so hard that a powerful rock-drill
(percussion plus rotation) could not drill with a four-cutting-tips
cutter - had to revert back to a carbide-tipped chisel-edge drill.
Implies that need a goodly blasting medium.

Indeed. Gelignite, or a NG-dynamite, seems called for.

Also, for a a small tunnel, AN-based explosives are generally less
useful - though they do make small diameter cap-sensitive AN emulsions,
AN-based explosives are generally better for larger charges.

You didn't say how long the tunnel is, but unless it is very long
jelly/NG might even be cheaper. It will certainly be more practical and
need less drilling.

BTW, Cranfield sometimes do a short course on mining explosives.

Peter Fairbrother

[Richard Smith]

Post by Peter Fairbrother
[...]

Post by Richard Smith

Post by Peter Fairbrother
Urea nitrate is sometimes used in home made explosives, but it is not
used in any civil explosives I know of, or for blasting purposes -
that's mostly the province of ANFO and water gels, with gelignites and
dynamites occasionally used on smaller scales and for demolition work.
Water gels and emulsion explosives are typically mixed on-site from
ammonium nitrate solutions plus fuels. They are usually not
cap-sensitive, though cap-sensitive ones do exist, and need a booster
explosive charge to detonate. The non-cap-sensitive ones are easier to
transport.
ANFO is also often made on site. Ammonium nitrate prills come in two
types, in one the prills are carefully engineered so that they will
absorb exactly the right amount of fuel oil if they are to be used in
ANFO explosives, and in the other they are engineered so they won't
absorb fuel oil if the AN is to be used as fertiliser.
Sorry, I don't have any practical experience in blasting tunnels. You
do usually need higher velocity explosives like dynamite or gelignite
for hard rocks though.
Peter Fairbrother

Thanks for that.
Since I posted this question I have learned a lot.
The "traditional" blasting medium used in Cornwall was gelignite.
I've had comment that cost would make you have second thoughts about
doing that to conform with tradition.

Yes, it is more expensive. As is NG-dynamite. However they are about
twice as powerful as ANFO, so you need less.

Post by Richard Smith
Brings ANFO to the fore now.
I've read about "emulsion". Seems is "the business" when you have a
big tanker driving around pouring into many big blasting holes.
"per-unit" cost very favourable - but the costs of maintaining a
storage of "ANBI", pumps to safely handle ANBI, etc. - the set-up and
maintenance costs - might have you looking at ANFO (?)

I'm unsure whether the AN used in ANFO is itself an ANBI - if AN is
prilled for explosives purposes it might well be. Or perhaps it is
controlled under one of the many AN control orders, which I have only
a passing familiarity with.
However there is another problem or three with ANFOs, AN water gels
and emulsions - they need bigger holes than NG-dynamites or
gelignites, as they will not explode properly when the diameter of the
hole is small.
In practice, combined with the fact that they are only about half as
powerful, you end up using a lot more. Which means a lot more nasty
gases to get out of your tunnel.
Second, they really need boosters. There are cap-sensitive gels and
emulsions, but then you are getting into the same legal hassles as the
higher velocity explosives - plus you need different certificates and
licenses for the boosters. Some people use detcord as a booster, but
the same requirement for an explosives certificate etc applies (in the
UK).
Third, and perhaps most important, especially when used for tunnels in
hard rock, they aren't really brisant enough to cope with hard
granite. The NG-based (or NC-based) high velocity explosives produce
shock waves which will fracture granite, but the lower velocity of
detonation of the AN-based explosives give more of a hard push than a
breaking shock.

Post by Richard Smith
The granite I met here is so hard that a powerful rock-drill
(percussion plus rotation) could not drill with a four-cutting-tips
cutter - had to revert back to a carbide-tipped chisel-edge drill.
Implies that need a goodly blasting medium.

Indeed. Gelignite, or a NG-dynamite, seems called for.
Also, for a a small tunnel, AN-based explosives are generally less
useful - though they do make small diameter cap-sensitive AN
emulsions, AN-based explosives are generally better for larger
charges.
You didn't say how long the tunnel is, but unless it is very long
jelly/NG might even be cheaper. It will certainly be more practical
and need less drilling.
BTW, Cranfield sometimes do a short course on mining explosives.
Peter Fairbrother

Thanks Peter
Amazing info.

I'll cover a later question first.
The tunnel would not be long. Metres to tens of metres if I infer
rightly.
Would be a crosscut from an existing working in one lode to intercept
another lode.
There are mine and mineral charts of the area which lead the
suggestion to be made. Far beyond me to even know what this
information is, let alone how to interpret it yet.

I'll go to another implicit question.
The new crosscut would be down a small decline I have not been down
yet. So I don't know if that part is granite (hard) or killas
[metamophosed sedimentary rock] (brittle; readily drilled).
About half the mine is hard granite (dry); about half is killas (like
standing in a shower sometimes).

So your point about "nitro" blasting material points to more
questions. Thanks - will pursue that.
Meaning the traditional very brisant blasting material.

If the crosscut is in hard granite then another constraint might
present itself - the drill-hole I tried was clearly the size for
sticks of jelly. That was running at about the claimed 0.3m/min with
the powerful rockdrill used
http://weldsmith.co.uk/tech/minerals/condurrow/231207_rockdrill1st/231224_holman_silver_900.html
"rock-drill of 07Dec2023 - Holman Silver 900"
This is apparently a monster machine which can only be used on hard
granite.
So if it's on its "sweet-spot" with a drill for jelly then a bigger
drill for ANFO might be beyond possible.
Noting this "mega" rock-drill cannot run a 4-tips jelly-sized cutter
in the hard granite - has to be a chisel-edge cutter.
Thanks for makign that point.

This is not a workplace. It's a hobby activity. So...
The only way drilling can be done is with a "carryable"
"human-operated" drill (cannot be a "jumbo").
Hence you might be raising a very good point.

Well, wow, thanks so much.

One of the enthusiusts / volunteers at the mine is sending me
info. and giving me some guidance.
So hopefully all will be well.

If you want to "PM" me there is a contact form on my website, at the
"Index" and other pages.

Best wishes and a successful happy new year,
Rich Smith

PS thanks for "Cranfield" lead. Did my welding engineer Masters
there, including my fatigue of metals / welds project. Could look
whether that blasting materials course can be done.

[Jim Wilkins]

"Richard Smith" wrote in message news:***@void.com...

Anyone here know about blasting person-height&width tunnels in hard
rock?
...
Then there is hard granite. Very hard. A 4-carbide-teeth drill bit
cannot touch some when driven by a rock-drill which can go 1~1/2metres
in minutes with a simple chisel-edged carbide-tipped drill bit.

------------------
I can't help with this. My only rock drilling experience is on granite
boulders with a Makita HR3851 rotary hammer drill I was given because it had
broken. I use it with wedges and shims to trim inconveniently protruding
outcrops.

Your comments on your technohistorical wanderings are always interesting.

https://www.amazon.com/Ancient-Engineers-Astonishing-Wonders-Creators/dp/0345482875
The author was a rare example of a scientifically literate historian:
https://en.wikipedia.org/wiki/L._Sprague_de_Camp

[Richard Smith]

Post by Richard Smith
Anyone here know about blasting person-height&width tunnels in hard
rock?
...
Then there is hard granite. Very hard. A 4-carbide-teeth drill bit
cannot touch some when driven by a rock-drill which can go 1~1/2metres
in minutes with a simple chisel-edged carbide-tipped drill bit.
------------------
I can't help with this. My only rock drilling experience is on granite
boulders with a Makita HR3851 rotary hammer drill I was given because
it had broken. I use it with wedges and shims to trim inconveniently
protruding outcrops.
Your comments on your technohistorical wanderings are always interesting.
https://www.amazon.com/Ancient-Engineers-Astonishing-Wonders-Creators/dp/0345482875
https://en.wikipedia.org/wiki/L._Sprague_de_Camp

I've seen breaking boulders by drilling a hole, putting in
semicircular taper wedges and driving a metal solid cylindrical wedge
down the middle (low friction?).

Seen chalcopyrite (sulfide copper ore) glistening in the fractured
section where it has been there hermetically sealed in the granite for
the 300million-ish years since it was deposited (not commercially
viable extraction, but there)

Thanks for the
Ancient-Engineers-Astonishing-Wonders-Creators
L._Sprague_de_Camp
hint - looks a good book to get.

I've just had a good week teaching welding (I said "No way!", they
said "Yes it will be fine", so I gave it a whirl and it worked).

So looking forward to finding out blasting as a part of mining over
the Christmas period. "Busperson's holiday" from what I have devoted
myself to (metallurgy and welding) over the decades.

Best wishes and season's greetings

[Leon Fisk]

On Tue, 19 Dec 2023 07:55:41 +0000
Richard Smith <***@void.com> wrote:

<snip>

Post by Richard Smith
So looking forward to finding out blasting as a part of mining over
the Christmas period. "Busperson's holiday" from what I have devoted
myself to (metallurgy and welding) over the decades.

Suspect you may find the book "The Anarchist Cookbook" of interest:

https://annas-archive.org/search?q=anarchist+cookbook+powell

several copies, different formats there. This maybe a decent pdf🤷

https://annas-archive.org/md5/e369ed0f88454868628e6395da158a30

Has quite a bit of info on explosives...

[Bob La Londe]

Post by Leon Fisk
On Tue, 19 Dec 2023 07:55:41 +0000
<snip>

Post by Richard Smith
So looking forward to finding out blasting as a part of mining over
the Christmas period. "Busperson's holiday" from what I have devoted
myself to (metallurgy and welding) over the decades.

https://annas-archive.org/search?q=anarchist+cookbook+powell
several copies, different formats there. This maybe a decent pdf🤷
https://annas-archive.org/md5/e369ed0f88454868628e6395da158a30
Has quite a bit of info on explosives...

I've often wondered if there is a legit copy of the anarachist cookbook
that isn't explicitly dangerous to the reader. The reason I say this is
I have never held a print copy. However many years ago with a different
frame of mind we once logged onto a server in France through a relay
that appeared to be a black market trading board. Lots of early scripts
and hacking tools, trading stolen credit card and bank account numbers.
That sort of thing. One thing in the archives was a text file claiming
to be the Anarchist Cookbook. We read many recipes, and most appeared
to be more annoying than anything else. A few were downright dangerous
to follow. I don't recall reading anything that was really good nuts
and bolts of destructive mixture/devices.

[Leon Fisk]

On Tue, 19 Dec 2023 13:04:40 -0700
Bob La Londe <***@none.com99> wrote:

<snip>

Post by Bob La Londe
I've often wondered if there is a legit copy of the anarachist cookbook
that isn't explicitly dangerous to the reader. The reason I say this is
I have never held a print copy. However many years ago with a different
frame of mind we once logged onto a server in France through a relay
that appeared to be a black market trading board. Lots of early scripts
and hacking tools, trading stolen credit card and bank account numbers.
That sort of thing. One thing in the archives was a text file claiming
to be the Anarchist Cookbook. We read many recipes, and most appeared
to be more annoying than anything else. A few were downright dangerous
to follow. I don't recall reading anything that was really good nuts
and bolts of destructive mixture/devices.

The original (Powell) was from 1971. Amazon reviewers (1 star) don't
think much of it... Thought it might give Richard a few grins or
possibly some ideas to search for better info😉

I see Amazon has several "More items to explore" that might treat
explosives in a better manner:

https://www.amazon.com/Anarchist-Cookbook-William-Powell/dp/1607966123/

[Richard Smith]

Post by Leon Fisk

...

The original (Powell) was from 1971. Amazon reviewers (1 star) don't
think much of it... Thought it might give Richard a few grins or
possibly some ideas to search for better info
...

:-)

[Richard Smith]

Thanks everyone for the amazing depth and knowledge of help you provided
on this topic.
While visiting family in Australia

* the neighbour had worked in a gold mine in Aus. and explained some
realities I was unsure about

That sent me looking / searching online and I found

* As presented in
http://www.weldsmith.co.uk/tech/minerals/240205_yt_goldmine/240205_yt_goldmine.html
"Thanks - Mt. Baker Mining and Metals "Opening My Gold Mine!" series"
All explained there.
Link to the "YouTube" "channel" where the 17 videos are. Which tell an
amazing story.

I learned a lot.

Best wishes to all,
Rich S