Ingo,
        An addendum to my previous message.  I should have added:
        As far as I was told a "fire boss" detonated the round(s) after
all the other miners had left the mine (for safety reasons -
particularly to avoid miners being trapped should methane gas in a coal
mine ignite from the blast).  In hard rock mines, a miner who had earned
a blasting certificate was entirely responsible for the blasting and no
shifter could order him to detonate a blast (or not to detonate one).
        This fact was very much responsible for my being trained by an
old timer for a full year after I had completed mining school.  Vic had
been asked by his shift boss to drill "test" holes.  Each time, Vic
obeyed, but told the shifter that he was a miner and "blasted any holes
that he drilled".  At a convenient time, Vic loaded all the "test" holes
(which he had aimed in an appropriate direction) and blasted them.  The
company became aware of this when the miners suddenly made $30.00 per
day contract (at a time when contract was held to $3.00 per day).
Because Vic was LEGALLY entitled to do what he did (and was too good a
miner to fire), he was SENTENCED to train a young miner for a year (and
fortunately for me, he chose me).
        I wrote the blasting test at the completion of mining school,
but all miners were required to have a full years experience before
being granted a permanent blasting certificate (we were issued an
"interim" certificate).  Needless to say, I met this requirement while
still working with Vic.
        Also, I did not mean to imply that an electrical boss had to be
present for wiring diamond drill blasts.  Geordy was probably only a
journeyman when this incident happened.
        The idea of blasting "experts" amuses me. While I was working
with Vic, another well-meaning miner gave me the following rule for
blasting: "Slow powder blows upward, medium powder blows sideways, and
fast powder blows downward.  Having first year university physics, I
found this ridiculous, and remarked on it to the old man.
        Vic then questioned me about my own theories of blasting
(involving equal pressures in all directions, inertia, etc.).  After I
had explained when I would use the different speeds of powder,  Vic
pointed out that this miners rule would "work" in all cases and was much
easier to explain to a young miner than my complicated theory.  When I
returned to university to major in physics, the wise old man's lesson
served me well.  Physics is interested only in "how" and "how much" not
in "why".  So many useful formulae are theoretically "not exactly
correct".



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