Arizona Administrative Code › Title 11 - MINES › Chapter 1 - STATE MINE INSPECTOR › Article 2 - EXPLOSIVES AND BLASTING › Section R11-1-273 - Initiating Blasts

Current through Register Vol. 30, No. 28, July 12, 2024
A. When fuse is
				used, the blast cap shall be securely attached to the safety fuse with a
				standard ring-type (or other approved) cap crimper.
B. No primers shall be assembled or fuse
				capped closer than 50 feet from any magazine.
C. Only wooden or non-sparking tools shall be
				used for making holes in a cartridge of explosives.
D. Explosives shall not be extracted from a
				hole that has once been charged or has misfired unless it is impossible to
				detonate the unexploded charge by insertion of a fresh additional
				primer.
E. If there are any
				misfires while using cap and fuse, all persons shall remain away from the
				charge for at least one hour. On electrical misfires, all persons shall remain
				away from the charge for at least 15 minutes. Electrical misfires shall be
				handled under the direction of the person in charge of the blasting and all
				wires shall be carefully traced and search made for unexploded
				charges.
F. Blasters, when testing
				circuits to charged holes, shall use only blasting galvanometers designed for
				this purpose.
G. Only the man who
				makes the leading wire connections in electrical firing shall fire the shot.
				All connections should be made progressively from borehole back to the source
				of firing current, and the leading wires shall remain shorted and not be
				connected to the blasting machine or other source of current until the charge
				is to be fired.
H. Blasts in shafts
				or winzes shall be initiated from a safe location outside the shaft or
				winze.
I. When blasting
				electrically, the electric blasting cap leg wire shunt shall not be removed
				from the leg wires until loading operations have been completed.
J. When firing from 1 to 15 blastholes with
				safety fuse ignited individually using hand-held lighters, the fuses shall be
				of such lengths to provide the minimum burning time specified in the following
				table for a particular size round:
Number of Holes in a Round
Minimum Burning Time, Minutes
1
2
2-5
2 2/3
6-10
3 1/3
11-15
5
In no case shall any 40-second-per-foot safety fuse less than
				  36 inches long or any 30-second-per-foot safety fuse less than 48 inches long
				  be used.
K. Not over 15
				fuses shall be spit by each blaster if being individually ignited. At least two
				men shall be present when lighting fuses, and no man shall light more than 15
				individual fuses. To avoid an unsafe delay in the operation, all men shall
				carry out the lighting of fuses simultaneously. If more than 15 holes per man
				are to be fired, igniter cord and connectors or electric blasting shall be
				used.
L. No fuse shall be used that
				burns faster than one foot in 30 seconds or slower than one foot in 55 seconds.
				The burning rate of every shipment of fuse received at a mine shall be
				determined. If a shipment of fuse lasts more than 60 days, the burning rate
				must be rechecked each 60 days. The burning rate of the safety fuse in use at
				any time shall be measured, posted in conspicuous locations, and brought to the
				attention of all men concerned with blasting.
M. Fuse shall be ignited with hot wire
				lighters, lead spitters, igniter cord or other such approved type device as
				designed for this purpose. Carbide lights shall not be used to light
				fuses.
N. Where electric blasting
				is to be performed, electric circuits to equipment in the immediate area to be
				blasted shall be de-energized before electric detonators are connected to the
				blasting circuit; the power shall not be turned on until after the shots are
				fired or the blast is deactivated by removing or shunting each electric
				detonator.
O. Trunklines, in
				multiple-row blasts initiated by detonating cord, shall make one or more
				complete loops, with crossties between loops at intervals of not over 200
				feet.