Electric

TM 9-1300-277

WARNING

b. Electric.

A MISFIRE WILL BE APPROACHED

BY THE PERSON IN CHARGE, OR

NOTE

WHO HAS THE MOST KNOWLEDGE

When preparing and using an

OF THE FIRING SYSTEM INVOLVED.

electric ignition train, all applicable

A SECOND PERSON WILL ACT AS A

safety precautions in paragraph 5-7

SAFETY BACKUP.

will be observed.

A misfire may occur in spite of all precautions.

Squibs and firing wiring will be

Therefore, working on or near a misfire is the most

tested prior to preparation of the

hazardous of all disposal operations. One qualified

ignition train; squibs in the same

person will examine the misfire with a second qualified

manner as electric blasting caps in

person acting as a safety backup. The safety backup

paragraph 5-8b; firing wire in

will stay clear of the immediate danger area. He will

accordance with paragraph 5-8c.

utilize natural barriers or obstructions for protection, but

remain in a position to observe the actions of the person

(1) Attach M1 flash-vented squib lead

examining the misfire. He will be prepared to go to the

wire to firing wire.

aid of the person examining the misfire if an accident

should occur.

(2) Secure bag to squib by taping top of

bag to squib lead wires.

5-25. PREVENTION OF NONELECTRIC MISFIRES

All safety precautions will be followed In

(3) Insert bag into combustible material

addition, the probability of a misfire may be reduced if

in pit.

the following procedures are adhered to:

(4) Attach firing wire to blasting

a. Prepare all initiators properly, ensuring use of

machine and operate in accordance with paragraph 5-

proper blasting cap.

11.

b. Place charges carefully.

5-24. MISFIRES

WARNING

c. Place initiator properly.

WAIT AT LEAST 30 MINUTES AFTER

EXPECTED

DETONATION

d. Perform any tamping operation with care to

IGNITION BEFORE APPROACHING

avoid damage to an otherwise carefully prepared

ANY MISFIRE.

IF IT CAN BE

charge.

POSITIVELY ASCERTAINED THAT

THE

FAILURE

STRICTLY

e. Ensure time blasting fuse is ignited prior to

ELECTRICAL IN NATURE, AND IT IS

withdrawing.

POSITIVELY KNOWN THAT THE

EXPLOSIVES ARE NOT BURNING,

f. Fire charge according to proper technique.

CORRECTIVE ACTION MAY BE

TAKEN IMMEDIATELY.

g. If possible, a dual firing system will be used. If

both initiators are properly assembled, the possibility of

NOTE

a misfire is reduced to a minimum.

The above warning applies to all

nonelectric firing systems, all dual

5-26. HANDLING NONELECTRIC MISFIRES

systems (figs. 5-23, 5-24, 5-25, and 5-

26), and to detonating cord primed

Nonelectric misfires will be handled as follows:

with nonelectric blasting caps. An

exception is made only for single

a. Nonelectric Blasting Cap Misfire.

electrical firing systems (one firing

circuit) and single detonating cord

firing systems primed with an

(1) Allow a minimum of 30 minutes after

electric blasting cap.

expected detonation before starting investigation.

Change 2

5-22