Blasting and Rock Breaking

[BlasterJ]

Hi all,

I'm new to the forum, but have been rock hounding, prospecting and doing abandoned mine rescue on a search & rescue team for about 15 years. I started with microblasting, and eventually got more training and acquired my own state blaster's license, ATF license and local permits.

If anyone has questions about drilling, breaking and blasting hard rock, I am happy to answer. I'm based out of Southern California.




Cheers,

John

 

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[Clay Diggins]

Welcome to Tnet John.

Thanks for offering to share your experience!

Heavy Pans

 

[HuntH2002]

Welcome from Texas

 

[pczim]

Hi and nice to have you here. Look forward to learning from you...

 

[BlasterJ]

Hi and nice to have you here. Look forward to learning from you...

So I've been doing a lot of R&D on small mining techniques. In my interpretation of USFS and BLM regs, you should probably have at least a "notice level" claim before you start using high explosives and moving serious rock. You're going to need to rent a Bobcat or excavator to muck it anyway, and "explosives" are spelled out in a lot of the publications as being in the same category as heavy equipment.

For a smaller mine project, you can drill the holes with the gas-powered Pionjar drill (up to about 6' deep) and shoot maybe 10 yards of in-place rock at a time without a lot of difficulty. Once you have a clean, free face mucked out, you can move a lot more material per shot and don't need to dig down to get it out. A properly designed blast can pre-fragment the rock and throw it in a particular direction.

If we're talking "recreational level" claims, my understanding is that "man portable" power tools are allowed. The lower end of "pyrotechnic blasting cartridges" or "non-explosive rock breakers" can plausibly be called a powder-actuated tool, especially if they have a metal tool component.

The EZ-break cartridges contain about 1g of smokeless powder and you can use up to 4 in an 18" deep hole. The Sierra Blaster uses a 10mm hole, and the cartridges are somewhat bigger. Using a cordless or electric hammer drill and one of those systems, you can move 1-4 cubic feet of rock per shot pretty reliably with these.



There are larger pyro cartridges available from Royex, Autostem and NXBurst. There are a few others that aren't commonly found in the U.S. They range from 20g to over 1kg in size, and can move many yards of rock if used in the correct spacing and quantity. They work great on free-standing boulders and work pretty well on rock with 1-2 free faces. Totally buried, in-situ rock requires a lot more product to get good fragmentation.


I have a manufacturing license and have been working on a 5-10g electric cartridge that works with in a 1/2" hole. This is still feasible for cordless drilling, and 24" SDS+ bits are pretty available.

I've also got a 40 gram cartridge that will split up a cubic yard boulder into small fragments. I drill these using a 1" Whirley bit on the gas drill.



The key to making these work is strong rock without a lot of cracks and stemming with tightly packed wet sand and/or a fabricated steel hole iron. The catridges will not explode if unconfined - they need to be completely contained in order to build up the 100K psi+ pressure they use to break the rock up.


Note that anything larger than the Sierra Blaster requires ATF licensing and other permits in the US. You need an ATF license and a magazine to use any amount of smokeless or black powder for blasting here, even though you can buy it over the counter for reloading. In Canada and some other places, packaged blasting cartridges like the Royex can be bought over the counter after you take a short training, much like the microblaster here.

 

[tamrock]

Your post left me to recall an old friend and customer of mine named Mel Dirksen of Pioneer Sales, who I knew for years years when I was a sales rep for Brunner & Lay. The man knew just about all there was to know about a Pionjar drill and his one man company focused specifically on that machine. Heck he even talked about me coming to work for him and learning all the ropes with the idea of taking over and buying him out, so he could retire. He did pretty good selling those drills to contractors and his biggest account was the US Forest Service. https://www.google.com/amp/s/www.legacy.com/amp/obituaries/denverpost/160934705

 

[BlasterJ]

Your post left me to recall an old friend and customer of mine named Mel Dirksen of Pioneer Sales, who I knew for years years when I was a sales rep for Brunner & Lay. The man knew just about all there was to know about a Pionjar drill and his one man company focused specifically on that machine. Heck he even talked about me coming to work for him and learning all the ropes with the idea of taking over and buying him out, so he could retire. He did pretty good selling those drills to contractors and his biggest account was the US Forest Service. https://www.google.com/amp/s/www.legacy.com/amp/obituaries/denverpost/160934705

They're great machines, and I don't know why they aren't more popular. Maybe cost. The newer model of the Pionjar is the Atlas Copco Combi, which sells for about $5K new. Rebuilt Pionjar 120s can be had for $1200-1500, or around the same price as a new Chinese knockoff that is not as good of quality.

I've rebuilt 3 of these so far and am waiting on parts for a 4th. One issue is that these are kind of weird and different, and regular small engine shops don't usually work on them. Parts from Sweden are also expensive. but I have an aftermarket supplier for a lot of the hard parts. The Cobra Combi shares a lot of the same mechanical parts, so they can also be rebuilt economically.

These units take 7/8x4 1/4" drill steels and there are a whole bunch of other tools available. I have a spade, tamper, moil point, ground rod driver and more. They hit about like a 55lb breaker in jackhammer mode.

If any of y'all have one that won't run, they are definitely worth rebuilding. They usually stop working when they get so filled up with crud (the 12:1 2-stroke fuel mix also lubricates the machinery) and rock dust that they won't run more than a few minutes. Or the rings are too worn out to hold any compression and they need a full overhaul.

Just got this one back together.


Crated up, they will fit in the trunk of a car.

 

[tamrock]

They're great machines, and I don't know why they aren't more popular. Maybe cost. The newer model of the Pionjar is the Atlas Copco Combi, which sells for about $5K new. Rebuilt Pionjar 120s can be had for $1200-1500, or around the same price as a new Chinese knockoff that is not as good of quality.

I've rebuilt 3 of these so far and am waiting on parts for a 4th. One issue is that these are kind of weird and different, and regular small engine shops don't usually work on them. Parts from Sweden are also expensive. but I have an aftermarket supplier for a lot of the hard parts. The Cobra Combi shares a lot of the same mechanical parts, so they can also be rebuilt economically.

These units take 7/8x4 1/4" drill steels and there are a whole bunch of other tools available. I have a spade, tamper, moil point, ground rod driver and more. They hit about like a 55lb breaker in jackhammer mode.

If any of y'all have one that won't run, they are definitely worth rebuilding. They usually stop working when they get so filled up with crud (the 12:1 2-stroke fuel mix also lubricates the machinery) and rock dust that they won't run more than a few minutes. Or the rings are too worn out to hold any compression and they need a full overhaul.

Just got this one back together.
View attachment 1818878

Crated up, they will fit in the trunk of a car.

We bought 6 new Chinese copy gas drills. When I first got my hands on one I about died of exhaustion trying to pull start the POS. One of our guys dinked around with the jets I believe and that got one to fire up better. I know we got one new one left and I'm not out all that hard trying to sell it, as I really don't want my name attached to such junk. I'm dealing with a mine now who are testing the autostems to open up an old heading to a 10' by 10' in order to mine with larger rubber tire haul trucks, LHDs and Jumbo drill. The place I work had just merged with the Midwest rockdrill company who manufacturers the former Gardener Denver S83 pneumatic rock drill. https://btemw.com

 

[BlasterJ]

We bought 6 new Chinese copy gas drills. When I first got my hands on one I about died of exhaustion trying to pull start the POS. One of our guys dinked around with the jets I believe and that got one to fire up better. I know we got one new one left and I'm not out all that hard trying to sell it, as I really don't want my name attached to such junk. I'm dealing with a mine now who are testing the autostems to open up an old heading to a 10' by 10' in order to mine with larger rubber tire haul trucks, LHDs and Jumbo drill. The place I work had just merged with the Midwest rockdrill company who manufacturers the former Gardener Denver S83 pneumatic rock drill. https://btemw.com

I've never actually run the Chinese one, so that's good to know. The originals can be rebuilt just fine 1-2 times before they need a new cylinder and piston. The ones I have purchased either got used like hell building trails, or sat around forever in a damp shed.

I'm thinking about trying a machine shop that skim bores and Nikasil plates motorcycle cylinders next time I build one. This should be a "better than original" build, although a little expensive.

Just curious: How does a drill like the S83 compare to a 55 or 90lb sinker drill like you'd use for surface drilling? What makes them so much more expensive - the pneumatic leg and lighter weight?

 

[Mad Machinist]

Anytime you go to a level of using explosives and heavy equipment you will need a plan of operations and proper bonding. At least this is what I was told by out new state director here and she is pro mining.

Here's a link to the BLM online bond calculator.

https://www.blm.gov/documents/arizo...d-calculation-spreadsheet-2018-bond-estimator

The BLM isn't gonna say much about a Sierra Blaster or anything with an engine under about 5 horsepower but much over that and your risking some serious fines.

 

[BlasterJ]

Anytime you go to a level of using explosives and heavy equipment you will need a plan of operations and proper bonding. At least this is what I was told by out new state director here and she is pro mining.

Here's a link to the BLM online bond calculator.

https://www.blm.gov/documents/arizo...d-calculation-spreadsheet-2018-bond-estimator

The BLM isn't gonna say much about a Sierra Blaster or anything with an engine under about 5 horsepower but much over that and your risking some serious fines.

Looking at the bond calculator, it seems like they see explosives as also a hazmat issue. It might be a good idea to specify that you will be using a contractor or never storing the fuel, cartridges, etc. on-site. I have seen mine sites with abandoned explosives here in California. BLM just cleaned one up.

 

[tamrock]

Just curious: How does a drill like the S83 compare to a 55 or 90lb sinker drill like you'd use for surface drilling? What makes them so much more expensive - the pneumatic leg and lighter weight?[/QUOTE]

The S83 jackleg complete is a much bigger and heavier machine built for high output for underground drifting and roof bolting, so yes with the leg and all its gonna be costing more than the average sinker drill, plus its built in the USA. Also it can be made as a HD sinker and a stoper drill which I just last month sold 6 to a silver mine so they can put in a drill and blast from the bottom up Alimak-raise shaft.

 

[BlasterJ]

Just curious: How does a drill like the S83 compare to a 55 or 90lb sinker drill like you'd use for surface drilling? What makes them so much more expensive - the pneumatic leg and lighter weight?

The S83 jackleg complete is a much bigger and heavier machine built for high output for underground drifting and roof bolting, so yes with the leg and all its gonna be costing more than the average sinker drill, plus its built in the USA. Also it can be made as a HD sinker and a stoper drill which I just last month sold 6 to a silver mine so they can put in a drill and blast from the bottom up Alimak-raise shaft.[/QUOTE]

Looks like a great machine, and you get what you pay for.

 

[tamrock]

The S83 jackleg complete is a much bigger and heavier machine built for high output for underground drifting and roof bolting, so yes with the leg and all its gonna be costing more than the average sinker drill, plus its built in the USA. Also it can be made as a HD sinker and a stoper drill which I just last month sold 6 to a silver mine so they can put in a drill and blast from the bottom up Alimak-raise shaft.

Looks like a great machine, and you get what you pay for.[/QUOTE]Indeed you gotta pay for the things build to perform, as that's the case with your Pionjar's. Form what I hear there's no better gas rockdrill out there. Thing with rockdrill, pneumatic, hydraulic, electric, or internal combustion they are all self destructing machines. A heavy operated MW 83 will average about $900. to $1200. in maintenance a month.

 

[BlasterJ]

Indeed you gotta pay for the things build to perform, as that's the case with your Pionjar's. Form what I hear there's no better gas rockdrill out there. Thing with rockdrill, pneumatic, hydraulic, electric, or internal combustion they are all self destructing machines. A heavy operated MW 83 will average about $900. to $1200. in maintenance a month.

Can that type of maintenance be done by the customer, or are they typically sent in for service/overhaul on a regular basis? Sounds like the basic platform is bulletproof and designed for service, unlike basically everything import.

So if I'm reading this correctly, Gardner-Denver originally made the machine and Midwest took it over? I have seen these sold under other names too - are they out of patent and knocked off, or do you let other companies rebrand them?

 

[tamrock]

Midwest was knocking off the GD machine before GD discontinued making and supporting the S83 in around the late 1980s if I recall. At one time we had a company in Japan making the S83. They came to us and we were ordering up as may as 250 a month. The company was called Toku and they built an excellent machine as they were probably the most modern state of art pneumatic tool manufacturer in existence. They manufactured much of Chicago Pneumatic's, Indersol Rand and other re-lable brands of all kinds of air tools from die grinders to jackhammers. Atlas Copco took over the company and their management decided to drop us because we couldn't produce the volume of business like Ingersoll Rand could which may have be as much as a 100% in revenue we could throw at em. Here recently Midwest with other investors have taken over the place I work, so I guess I'm only gonna be pushing the Midwest product as of now. I have sold and supported a fair amount of the Canadian built pneumatic rock drills over the years, but those aren't the preferred machine by American miners. Great Canadian built machines, but the Canucks prefer theirs over ours. Thing is there's a lot of Canadian mining people in this country and we'll still keep providing support on those unless the new powers tell me different.

 

[tamrock]

Can that type of maintenance be done by the customer, or are they typically sent in for service/overhaul on a regular basis? Sounds like the basic platform is bulletproof and designed for service, unlike basically everything import.

So if I'm reading this correctly, Gardner-Denver originally made the machine and Midwest took it over? I have seen these sold under other names too - are they out of patent and knocked off, or do you let other companies rebrand them?

Most mine maintenance fix their own rockdrills. Midwest began manufacturing an identical copy of the original Gardner Denver, I guess after the patent ran out on GD and GD just discontinued producing it. Gardner Denver pretty much gave up on all their pneumatic tool line, jackhammers, chippers and others when so many more import brands came along in the late 70s and early 80s. Garden Denver is still around producing mostly stationary industrial air compressors and other machinery, such as hydraulic track drills, which I believe Caterpillar took over now recently. At one time GD made just about every kind of pneumatic equipment a small mine operation would need like overshot muckers, slushers and rock drilling bits and rods. I guess they got out of all that because the smaller mining operations just became less and less.

 

[BlasterJ]

Most mine maintenance fix their own rockdrills. Midwest began manufacturing an identical copy of the original Gardner Denver, I guess after the patent ran out on GD and GD just discontinued producing it. Gardner Denver pretty much gave up on all their pneumatic tool line, jackhammers, chippers and others when so many more import brands came along in the late 70s and early 80s. Garden Denver is still around producing mostly stationary industrial air compressors and other machinery, such as hydraulic track drills, which I believe Caterpillar took over now recently. At one time GD made just about every kind of pneumatic equipment a small mine operation would need like overshot muckers, slushers and rock drilling bits and rods. I guess they got out of all that because the smaller mining operations just became less and less.

There's still lots of good equipment like that at auctions and in people's yards if you know where to look. The really small operations I have seen get around some of the regulations by virtue of everyone being a partner and thus having no employees. Some of that stuff probably can't be used at all anymore, such as heavy equipment that isn't factory-equipped with ROPS (roll over protection) and similar.

 

[Mad Machinist]

Most mine maintenance fix their own rockdrills. Midwest began manufacturing an identical copy of the original Gardner Denver, I guess after the patent ran out on GD and GD just discontinued producing it. Gardner Denver pretty much gave up on all their pneumatic tool line, jackhammers, chippers and others when so many more import brands came along in the late 70s and early 80s. Garden Denver is still around producing mostly stationary industrial air compressors and other machinery, such as hydraulic track drills, which I believe Caterpillar took over now recently. At one time GD made just about every kind of pneumatic equipment a small mine operation would need like overshot muckers, slushers and rock drilling bits and rods. I guess they got out of all that because the smaller mining operations just became less and less.

So now we build our own. Hydraulics and pneumatics really are not that hard to understand. Just have to be smart about discharging all pressure before maintenance activitles.

 

[Mad Machinist]

There's still lots of good equipment like that at auctions and in people's yards if you know where to look. The really small operations I have seen get around some of the regulations by virtue of everyone being a partner and thus having no employees. Some of that stuff probably can't be used at all anymore, such as heavy equipment that isn't factory-equipped with ROPS (roll over protection) and similar.

I have a guy local to me here that has acres of the stuff. Most is beyond repair butbit does make for a good pattern to follow.