Ariz. Admin. Code § 11-1-273

Current through Register Vol. 30, No. 50, December 13, 2024

Section R11-1-273 - Initiating Blasts

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.

Ariz. Admin. Code § R11-1-273

Former Rule 2:73.