Is anyone aware of any studies into the ‘real-world’ life/viability of ICI/Orica Powergel 500 cartridges and IXI/Orica No 8 detonators once buried for seismic surveys in a sand environment? Quoted shelf-life is 12 months but I’m trying to make a considered assessment for cartridges and detonators that have been buried for a number of years. Cheers and thanks
Unlike NG products the manufacturer will give 12 months self life on this product.
These products degrade to safety once time as passed unlike NG products.
So one would expect after a year down a shot hole it will loose most of its performance and would be difficult to initiate if the Detonator was still intact in cartridge.
Again dealing with this needs the same precautions as dealing with any unexploded products in any shot hole
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Unfortunately I have no information relating to the shelf life of this particular product
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Considering the environment in which they have been placed I would suggest that you contact Orica UK.
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Hi, I work for RPS Explosives Engineering Services we conducted a program in the Middle East for an O&G company to locate, recover, inspection and render safe “misfired” seismic charges within the clients concession. Obliviously I can’t discus further in an open forum but if you contact me directly we can speak further under an NDA.
Regards Dave H
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The explosive properties of the material will remain long after the performance has degraded past the point of normal use. Depending upon the conditions, the Powergel may or may not therefore remain hazardous. The detonators will probably remain viable for many years and will remain hazardous: if damaged or corroded they should certainly not be used and must be handled with extreme caution. I am not aware of any formal study into explosives life under the circumstances described.
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I would concur with Ian McKay’s comments.
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I have known Powergel to miss fire after as little as 6 months but it is the detonators you need to be concerned about. If they are instant dets they could certainly work after 25 years or more, particularly if the sand is dry and non-corrosive. Delay detonators may not initiate from the fuse head as the delay compounds do breakdown but the petn charge may still be explosive.
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OK, so here at S&T for instruction purposes I rely on donated explosives, much of which is a bit long in the tooth. In my experience Dynamites can last well over 3 years depending on their Ammonium and Sodium Nitrate content (which makes them degrade quicker). Emulsions depending on the emulsifier can last many years. I have just finished using some top end product that was nearly 3 years old and still shot really well. In the past I have shot 4 year old 1.1 product with success. We have had cases where some emulsions including Emulite that was found by a construction contractor that used to blast was still in good enough condition to shoot and it was over 10 years old. So it depends on whether it is 1.1 or not and how good/expensive a product it is. A gassed emulsion will degrade faster than one with micro balloons and a poor emulsifying agent in a cheaper emulsion will usually result in recrystallization of the AN in a year or so. You can tell when an emulsion is getting old and suspect when the chub starts to get crinkles in it, this is a sign of the gas bubbles collapsing.
Regarding caps: electric caps don’t tend to be reliable after 25 years in general even when stored in magazines. Once they start going bad they all tend to go bad in rapid order, same for shock tube caps and dog bones.
The oldest electric caps in my mags have a date code of 14FE01 and they are still fully functional. My oldest shock tube caps are go back to 1995 and are getting a little suspect so every year I test shoot 20 of them to make sure they are still functioning correctly.
Hopefully this has been of some use.
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