7 CCR 1101-9-6-3 - Electric Initiation of Blasts
(A) Electric
detonators may be used for blasting operations in congested districts, or on
highways, or adjacent to highways open to traffic, except where sources of
extraneous electricity make such use dangerous.
(B) Electric detonator wires shall be kept
short-circuited (shunted) until they are connected into the circuit for
firing.
(C) Signs shall be posted
warning against the use of mobile radio transmitters on all adjacent highways
and roads.
(D) Mobile radio
transmitters that are less than 100 feet away from electric detonators shall be
de-energized and effectively locked when the detonators are not in the original
containers.
(E) Electric detonators
shall be used in compliance with the recommendations of IME with regard to
blasting in the vicinity of radio transmitters as stipulated in Safety Guide
for the Prevention of Radio Frequency Radiation Hazards in the Use of
Commercial Electric Detonators (Blasting Caps), IME Safety Library Publication
No. 20, December 2011.
(F)
Precautions in accordance with the recommendations of IME with regard to
blasting in the vicinity of radio transmitters as stipulated in Safety Guide
for the Prevention of Radio Frequency Radiation Hazards in the Use of
Commercial Electric Detonators (Blasting Caps), IME Safety Library Publication
No. 20, December 2011 shall be taken to prevent accidental discharge of
electric detonators from current induced by radar, cellular telephones, radio
transmitters, battery contact, lightning, adjacent power lines, static
electricity, dust storms, blowing snow or other sources of extraneous
electricity.
(G) Before adopting
any system of electrical firing, the blaster shall conduct a thorough survey
for extraneous currents, and all dangerous currents shall be eliminated before
any holes are loaded.
(H) In any
single blast using electric detonators, all detonators shall be of the same
style or function and be of the same manufacture.
(I) Electric blasting shall be carried out by
using blasting circuits or power circuits, in accordance with the electric
detonator manufacturer's recommendations.
(J) The firing line shall be checked with an
approved testing device at the terminals before being connected to the blasting
machine or other power source.
(K)
The circuit, including all detonators, shall be tested with an approved testing
device before being connected to the firing line.
(L) When firing a circuit of electric
detonators, care shall be exercised to ensure that an adequate quantity of
delivered current is available, in accordance with the manufacturer's
recommendation.
(M) Connecting
wires and lead wires shall be insulated single solid wires of sufficient
current- carrying capacity and shall not be less than #20 gauge (American wire
gauge) solid core insulated wire.
(N) Firing line or leading wires shall be
solid single wires of sufficient current carrying capacity, and shall be not
less than #14 gauge (American wire gauge) solid core insulated wire. Bus wires
depend on the size of the blast, but #14 gauge (American wire gauge) copper is
recommended.
(O) The ends of lead
wires which are to be connected to a firing device shall be shorted by twisting
them together or otherwise connecting them before they are connected to the leg
wires or connecting wires, and they shall be kept in the possession of the
person who is doing the loading until loading is completed and the leg wires
attached. Lead wires shall not be attached to the firing device until the
blaster is ready to fire the shot and must be attached by the
blaster.
(P) The ends of the leg
wires on electric detonators shall be shorted in a similar manner and not
separated until all holes are loaded and the loader is ready to connect the leg
wires to the connecting wires or lead wires.
(Q) When firing electrically, the insulation
on all firing lines shall be adequate and in good condition.
(R) A power circuit used for firing electric
detonators shall not be grounded.
(S) When firing from a power circuit, the
firing switch shall be locked in the open or "off" position at all times,
except when firing. It shall be so designed that the firing lines to the cap
circuit are automatically short-circuited when the switch is in the 'off'
position. Keys to this switch shall be entrusted only to the blaster.
(T) Blasting machines shall be in good
condition and the efficiency of the machine shall be tested periodically to
make certain that it can deliver power at its rated capacity.
(U) When firing with blasting machines, the
connections shall be made as recommended by the manufacturer of the electric
detonators used.
(V) The number of
electric detonators connected to a blasting machine shall not be in excess of
its rated capacity. A series or circuit shall contain no more detonators than
the limits recommended by the manufacturer of the electric detonators in
use.
(W) The blaster shall be in
charge of the blasting machines, and no other person shall connect the leading
wires to the machine.
(X) Blasters,
when testing circuits to charged holes, shall use only blasting testers
especially designed for this purpose.
(Y) In electrical firing, only the person
making leading wire connections shall fire the shot. All connections shall be
made from the borehole back to the source of firing current, and the lead line
wires shall remain shorted and not be connected to the blasting machine or
other source of current until the charge is to be fired.
(Z) After firing an electric blast from a
blasting machine, the leading wires shall be immediately disconnected from the
machine and short-circuited.
(AA)
When electric detonators have been used, workers shall not return to misfired
holes for at least thirty minutes.
Notes
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