drgjs Posted June 20, 2014 Posted June 20, 2014 (edited) ***ADVISORY: these rock breaking propellants are not the same as what you put in model rockets or otherwise. You must not try this at home**** This post is about some potentially high impact technologies under development, which have lead to some really interesting scientific advances along the way. There is little peer review work I can offer, due to this being truly industry and market driven R&D. However, there is plenty of video evidence from around the world and I have made a playlist here https://www.youtube.com/playlist?list=PLXlGYIt2uJKP4XoLQ1GWlrZJLm4w9_yxx The 2nd and 3rd of these intriguing articles we were involved with, but the rest are completely independent. The scientific challenge is to perfect the next generation of "breaking engines" for rock blasting and demolition, using similar classes of materials to rocket fuels ("propellants") to break, instead of high explosives. While in rockets, a propellant's main function is provide maximum thrust and controlling the chamber pressure is essential. here the challenge is to keep the **specially designed*** propellant confined in the drill hole for as long as possible. In other words we want to produce maximum pressure, without the exhaust gases venting at all. The results can be astonishing. I hope you find these videos as fascinating and thought provoking as I do. Edited June 20, 2014 by drgjs
Acme Posted June 20, 2014 Posted June 20, 2014 Looks cool. But hey, who doesn't like watching things blow up in slo-mo? What are the benefits over conventional explosives? Cheaper? Safer? Smaller drill holes? Lighter weight? Other? 1
drgjs Posted June 20, 2014 Author Posted June 20, 2014 (edited) Looks cool. But hey, who doesn't like watching things blow up in slo-mo? What are the benefits over conventional explosives? Cheaper? Safer? Smaller drill holes? Lighter weight? Other? Cheaper - potentially, because we need barely any to break the rock. Those concrete cylinders had charges of 4g. A spoonful. Safer - YES. These cartridges do not explode until they are confined. They cannot go bang even in a fire unless they are completely confined by something. They are so safe they can be sent by courier. Imagine doing that with explosives. But also because the pressures they generate are more commensurate with the rock strengths they do no produce the excessive noise, vibration of dust that high explosives do. Commercial explosives produce pressures of a few gigapascals - thats 100,000 atmospheres. The tensile strength of rock is in the 10 megapascal range. These are now in use underground mining, quarrying and concrete removal as well as other applications. Edited June 20, 2014 by drgjs
Acme Posted June 20, 2014 Posted June 20, 2014 Cheaper - potentially, because we need barely any to break the rock. Those concrete cylinders had charges of 4g. A spoonful. Safer - YES. These cartridges do not explode until they are confined. They cannot go bang even in a fire unless they are completely confined by something. They are so safe they can be sent by courier. Imagine doing that with explosives. But also because the pressures they generate are more commensurate with the rock strengths they do no produce the excessive noise, vibration of dust that high explosives do. Commercial explosives produce pressures of a few gigapascals - thats 100,000 atmospheres. The tensile strength of rock is in the 10 megapascal range. These are now in use underground mining, quarrying and concrete removal as well as other applications. So the propellant is similar to what we find in Estes model rocket engines? I noticed in one of the concrete barrel tests that the igniter was ejected out the top; was this a failure of the seal? 1
drgjs Posted June 20, 2014 Author Posted June 20, 2014 So the propellant is similar to what we find in Estes model rocket engines? I noticed in one of the concrete barrel tests that the igniter was ejected out the top; was this a failure of the seal? No. Estes engines are black powder if I recall compressed into a solid motor with a hole down the middle. Not right for this job. Please don't try this at home folks whatever you do!!! The rock breaking cartridges are special, as are the igniters as are the other bits and bobs. This does not mean makeshift things are safe - they are not and we witnessed some hazards in a quarry where they were using loose black powder just the other day. Some of the science is in the chemistry or formulation of these new mixture which is designed for safety and performance factors. Not its not the igniter ejecting its part of the "confinement engine".
Acme Posted June 20, 2014 Posted June 20, 2014 No. Estes engines are black powder if I recall compressed into a solid motor with a hole down the middle. Roger. Just asked as you used the terms 'rocket science' and 'rocket propellant'. I didn't know Estes engines were black powder, so thanks for that info. Not right for this job. Please don't try this at home folks whatever you do!!! The rock breaking cartridges are special, as are the igniters as are the other bits and bobs. This does not mean makeshift things are safe - they are not and we witnessed some hazards in a quarry where they were using loose black powder just the other day. Some of the science is in the chemistry or formulation of these new mixture which is designed for safety and performance factors. Roger. Appreciate your adding disclaimer to OP. Not that I had any intentions of trying this at home, or out at the mine on my own. Nice to know about the stuff though. Should the need arise to seek out professionals I have some idea what to ask for. Not its not the igniter ejecting its part of the "confinement engine". Did that lessen the effectiveness of the shot? Was it one of the stemming plugs shown in the last video?
drgjs Posted June 20, 2014 Author Posted June 20, 2014 (edited) Roger. Just asked as you used the terms 'rocket science' and 'rocket propellant'. I didn't know Estes engines were black powder, so thanks for that info. Roger. Appreciate your adding disclaimer to OP. Not that I had any intentions of trying this at home, or out at the mine on my own. Nice to know about the stuff though. Should the need arise to seek out professionals I have some idea what to ask for. Did that lessen the effectiveness of the shot? Was it one of the stemming plugs shown in the last video? Yes realized was drawing parallels too closely in attempt to put things in familiar terms. Source for black powder info is internet - might want to double check. Some commercial motors are AP. With black powder ones you have to be a little careful as if you damage motor you get cracks in the compressed powder I believe. This makes burn rate quicker and pressures higher than one might expect. Having said that model rocketry is very safe hobby according to statistics. It made the breakage different. In all those shots, the cartridges are exactly the same, its other things in the hole which makes difference [apart from cases where there are two cartridges per block - 4,7,8,11 if i recall]. No, these plugs are brand new design - we are going to put them to the test soon. Edited June 20, 2014 by drgjs
Acme Posted June 20, 2014 Posted June 20, 2014 Yes realized was drawing parallels too closely in attempt to put things in familiar terms. Catchy title never hurts. Source for black powder info is internet - might want to double check. Some commercial motors are AP. Roger. Checked and said Estes was black powder. I never cared for the stuff in my persussion-cap pistol and used Pyrodex instead. (Until their factory blew up anyway. ) With black powder ones you have to be a little careful as if you damage motor you get cracks in the compressed powder I believe. This makes burn rate quicker and pressures higher than one might expect. Having said that model rocketry is very safe hobby according to statistics. Yep; pretty safe as long as you observe the rules & regulations. Seems the biggest concern these days is setting fires. It made the breakage different. In all those shots, the cartridges are exactly the same, its other things in the hole which makes difference [apart from cases where there are two cartridges per block - 4,7,8,11 if i recall]. No, these plugs are brand new design - we are going to put them to the test soon. Good info. Sounds like a blast.
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