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
On 12/17/2023 11:56 AM, Richard Smith wrote:
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
The folk here damn' well know about all this stuff, but looking to
other views. Other cultures of mining. Looking to learn.
On Sun, 17 Dec 2023 20:08:02 +0000
Richard Smith <null@void.com> wrote:
<snip>
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"
--
Leon Fisk
Grand Rapids MI
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).
On 12/17/2023 2:08 PM, Richard Smith wrote:
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 .
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 .
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 <none@none.com99> writes:
On 12/17/2023 11:56 AM, Richard Smith wrote:
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).
"Richard Smith" wrote in message news:lyr0jk64l5.fsf@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
On 12/17/2023 1:08 PM, Richard Smith wrote:
Bob La Londe <none@none.com99> writes:
On 12/17/2023 11:56 AM, Richard Smith wrote:
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.
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.
On Tue, 19 Dec 2023 07:55:41 +0000
Richard Smith <null@void.com> wrote:
<snip>
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...
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
...
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.
On 18/12/2023 7:24 am, Bob La Londe wrote:
On 12/17/2023 1:08 PM, Richard Smith wrote:...
Bob La Londe <none@none.com99> writes:
On 12/17/2023 11:56 AM, Richard Smith wrote:
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
...
"Richard Smith"Â wrote in message news:lybkaoe9k3.fsf@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: https://www.youtube.com/watch?v=i6k26SJFyB8
"Richard Smith" wrote in message news:lybkaoe9k3.fsf@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."
--------------------------------------- https://www.sunritadrillbit.com/holman-303-rock-drill/
What is "lofty-quality steel"?
"Richard Smith" wrote in message news:lyv88kdqtd.fsf@void.com...
"Jim Wilkins" <muratlanne@gmail.com> writes:
---------------------------------------
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?
"Jim Wilkins" <muratlanne@gmail.com> writes:
"Richard Smith" wrote in message news:lyv88kdqtd.fsf@void.com...
"Jim Wilkins" <muratlanne@gmail.com> writes:
---------------------------------------
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.
On Wed, 27 Dec 2023 23:10:16 +0000, Richard Smith <null@void.com>From my experience about sixty years ago, the crew opperating a
wrote:
"Jim Wilkins" <muratlanne@gmail.com> writes:
"Richard Smith" wrote in message news:lyv88kdqtd.fsf@void.com...
"Jim Wilkins" <muratlanne@gmail.com> writes:
---------------------------------------
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:
.<https://www.youtube.com/watch?v=VmIhSh_7gVA>
Joe Gwinn
On Wed, 27 Dec 2023 18:51:25 -0500, Joe Gwinn <joegwinn@comcast.net>
wrote:
...
I've never seen a diesel hammer in action.
Seen air-driven and hydraulic.
I've seen diesel pile-drivers in action. Like this:
.<https://www.youtube.com/watch?v=VmIhSh_7gVA>
Joe Gwinn
From my experience about sixty years ago, the crew opperating a
"Delmag" pile driver, wear black (beige when new) coverals!
Speaking of weird lawnmowers, I helped restore an MTD Yard Bug. >https://www.ebay.com/itm/175849445818
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.
On Thu, 28 Dec 2023 08:00:42 -0500
"Jim Wilkins" <muratlanne@gmail.com> wrote:
<snip>
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
You know you might be overdoing arcane interests when you get strange
dreams on the topic... :-)
"Richard Smith"Â wrote in message
news:ly5y0iov83.fsf@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.
Gerry <geraldrmiller@yahoo.ca> writes:
On Wed, 27 Dec 2023 18:51:25 -0500, Joe Gwinn <joegwinn@comcast.net>
wrote:
...
I've never seen a diesel hammer in action.
Seen air-driven and hydraulic.
I've seen diesel pile-drivers in action. Like this:
.<https://www.youtube.com/watch?v=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?
...
She also caught Covid there.
...
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!
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.
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
Gerry <geraldrmiller@yahoo.ca> writes:Goo description.
...
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?
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
On 17/12/2023 23:24, Bob La Londe wrote:
[...]
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
I think urea is the same as ammonium nitrate.
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.
Peter Fairbrother <peter@tsto.co.uk> writes:[...]
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 (?)
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.
On 30/12/2023 23:13, Richard Smith wrote:
Peter Fairbrother <peter@tsto.co.uk> writes:[...]
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.
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.
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" wrote in message news:lybkaoe9k3.fsf@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."
...
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.
...
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.
...
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,
...
"Jim Wilkins" wrote in message news:un2c3s$2u4u6$1@dont-email.me...
His style reminds me of Ambrose Bierce.
https://www.gutenberg.org/files/972/972-h/972-h.htm
On 12/20/2023 9:19 AM, Jim Wilkins wrote:
"Richard Smith"Â wrote in message news:lybkaoe9k3.fsf@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:
https://www.youtube.com/watch?v=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 !
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.
On 20/12/2023 21:59, Snag wrote:
On 12/20/2023 9:19 AM, Jim Wilkins wrote:...
"Richard Smith"Â wrote in message news:lybkaoe9k3.fsf@void.com......
...
Peter Fairbrother
"Richard Smith" wrote in message news:lyh6jpm797.fsf@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"Â wrote in message news:lyfrz9j62y.fsf@void.com...
"Jim Wilkins" <muratlanne@gmail.com> writes:
"Richard Smith"Â wrote in message news:lyh6jpm797.fsf@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.
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
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.
On 06/01/2024 21:17, Richard Smith wrote:
[...]
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
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.
Could you blast with black powder as a historical re-enactment without official hindrance?
On 3/24/2024 4:22 PM, Jim Wilkins wrote:
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 .
On 3/24/2024 2:39 PM, Snag wrote:
On 3/24/2024 4:22 PM, Jim Wilkins wrote:
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.
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 .
Snag <Snag_one@msn.com> on Sun, 24 Mar 2024 18:58:12 -0500 typed in rec.crafts.metalworking the following:
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.
Could you blast with black powder as a historical re-enactment without official hindrance?
"Jim Wilkins" <muratlanne@gmail.com> writes:
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.
negligible knowledge but - with stemming like grit the worse that can
happen is a rain of grit particles - cannot become a high-velocity projectile.
On the other hand I have seen videos of blasts being covered by all
sorts of things.
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 .
On Sun, 24 Mar 2024 20:59:06 -0500
Snag <Snag_one@msn.com> wrote:
<snip>
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 .
Tannerite can make some pretty good blows too😉
https://www.youtube.com/results?search_query=tannerite+barn+blow
On 3/25/2024 2:59 AM, Richard Smith wrote:
"Jim Wilkins" <muratlanne@gmail.com> writes:
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.
Its can also reasonably be made in a home shop.
On 3/25/2024 3:15 PM, Leon Fisk wrote:
On Sun, 24 Mar 2024 20:59:06 -0500
Snag <Snag_one@msn.com> wrote:
<snip>
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 .
Tannerite can make some pretty good blows too😉
https://www.youtube.com/results?search_query=tannerite+barn+blow
 Yeah , but doesn't Tannerite require a sharp impact to set it off ? Besides , I already have the Pyrodex ...
On 3/25/2024 2:02 PM, Snag wrote:
On 3/25/2024 3:15 PM, Leon Fisk wrote:
On Sun, 24 Mar 2024 20:59:06 -0500
Snag <Snag_one@msn.com> wrote:
<snip>
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 .
Tannerite can make some pretty good blows too😉
https://www.youtube.com/results?search_query=tannerite+barn+blow
  Yeah , but doesn't Tannerite require a sharp impact to set it off ?
Besides , I already have the Pyrodex ...
Commercial Tannerite does require a VERY sharp impact to set it off. generally from a high power rifle. I seem to recall there is a formula
that can be set off by a rim fire rifle impact, and a local associate of
mine claims there is a formulation he worked with that can be set off by
just fuse. His claim is the only one I have ever heard about
"Tannerite", but there are lots of "explosives" formulations that can be made. Mythbusters supposedly were working on one of their dropped
projects when they discovered a very easy one made with very common
household products. They opted to drop that project and swear not to
reveal it to the public. Adam Savage mentioned it in on his TESTED
YouTube channel a while back.
On 3/25/2024 2:59 AM, Richard Smith wrote:
"Jim Wilkins" <muratlanne@gmail.com> writes:
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.
Its can also reasonably be made in a home shop.
Thanks Peter for explaining all this to our across-the-Atlantic cousins.
Very much more restrictive here.
It is so normal to go up to the counter at the club and buy a box of
rounds for your host's handgun you are going to have a go with - in the
sense of being repectful of your host's hospitality - normal in the US.
Not here. No part of any of it is permitted.
Black powder licence to have typically a kilo provided you are a member
of a registered firearms club and have a firearms licence is fairly
readily had I gather.
"Peter Fairbrother" wrote in message news:uu2vuv$3d2k0$1@dont-email.me...
https://www.euronews.com/green/2023/11/23/this-english-city-is-banning-gas-stoves-in-new-homes-heres-why
...
I had <okay - self-sensoring here> - a go - with a smoothbore
reproduction flintlock pistol.
Some kick - best 20 grains you ever got - and when the pall of smoke
cleared couldn't believe how close to the bullseye the shot had landed.
Oh yes - missed out staring through a purple haze of the pan flaring for
what seemed enough time to real Tolstoy's "War and Peace" before that enormous bang and recoil.
In Britain you have to understand that this can only be licenced if it's
an absolutely serious sport and dedication.
No implication of fun and levity is implied or intended.
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