Test Gear

[pwdrive]

Paul,

Amongst other things I imagine, it's used for testing explosive bolts. See here
http://www.richardsradios.co.uk/safety.html

Andrew

We had similar instruments when I was mining, they used to limit the current to a safe level when we were checking an explosive round that had been fired by the exploder but the round failed to go off, as a supplementry note of interest (maybe)
the first time I was sent in to do it I was a bag of nerves! We had just finnished drilling about thirty two 8ft holes plus the cut in a granite tunnel round, each hole apart from the center cut hole was primed with a stick of dynamite and a detonator then all the holes were rammed tight with dynamite, all the detonators are twist wired in series with the pair of wires from the exploder connected to the two ends of the series circuit.
Any way I must have done this a hundred times or more, however this time when we wound the exploder up and pressed the fire button 'nowt happened, muggins here was sent in to rectify the problem, it's a strange and erie feeling as when you walk up to the face all is quite exept for the dripping of water etc and you are all on your own standing in front of what amounts to a fully primed box of dynamite, the procedure was to break the circuit roughly in the middle and check either half for O/C connection and so on 'till you found the duff detonator then stuff a replacement detonator in the face end of the dynamite, then go back and fire the expoder, it always fired second time round...two duff detonators in a row would be a bad omen I think.
The safety proceedure for a missfire using electric detonators was to wait for 5 mins. after the first attempt at firing before going in to sought it out.
If using cut saftey fuses, (the ones that are lit like in the cowboy films) the proceedure was to wait 20 Mins before going in to sort it out, I have to say they were the worst.

Lawrence.