Demolitions & Military Engineering

Introduction to Demolitions

• Engineer units typically handle large-scale demolitions, excluding those from bombardments
• The army uses sappers for a variety of engineering tasks including bridging, road work, airfields and water
• Sappers are not usually available for non-engineering tasks

Troop Withdrawals and Explosives

• Troop withdrawals may necessitate abandoning equipment and vehicles including secret components
• Enemy equipment may need to be destroyed if recapture is imminent
• Explosives are the best way to deny utility of materials to the enemy
• Time constraints, scattered targets, and the need for sappers for specialized engineering skill necessitate training personnel in all arms in the use of standard explosives

Explosives for Engineering

• Explosives can be used for destructive and constructive purposes
• Charges can be used to loosen hard ground to more easily create positions, gunpits, and vehicle emplacements

Pamphlet Information

• Pamphlet No. 3 contains limited detail for all arms personnel
• This aligns with the policy on explosives use(Annex A)
• All arms personnel may protect bridges prepared for demolition, while preparation/execution is the Engineer's responsibility
• The pamphlet includes all-arms aspects with emphasis on demolition guard commander duties
• Chapter 5 discusses advancements in demolition explosives and equipment
• Annex D contains a training sequence for unit instructors

Types of Explosives

• Explosives are divided into "low" and "high" explosives
• Low explosives are chemical substances that burn very quickly - creating a lot of gas to remove obstacles
• They possess a high oxygen content, so they don't need external air to burn
• Gunpowder and cordite serve as examples; Cordite serves as a propellant for shells, bullets etc, and gunpowder acts as an igniting agent
• High explosives are chemical substances which detonate by shock, friction, or heat
• Detonation is an almost instantaneous conversion to gas in a “shock” wave
• High explosives produce an intense, shattering blow in addition to gas pressure
• Example: one pound of high explosive can cut a steel rail, where gunpowder would not
• High explosive shells are propelled by a low explosive like cordite contained within

Initiation of explosives

• "Initiation" constitutes the process for causing a high explosive to detonate
• Personnel must recognize and correct faults in firing circuits
• Service explosives are stabilized and need a substantial shock to detonate
• High explosives are detonated with a primer, a sensitive charge itself requiring initiation via detonator or cord
• Like lighting a coal fire, the fuze is the match, the detonator is the paper, the primer is the wood, and the explosive charge is the coal

Explosive Supply

• Explosives and accessories are ordnance supplied
• Field explosives are carried in explosive lorries
• Annex B compares the TO&E holdings of an engineer battalion and infantry battalion
• Only the explosives used by every one armed service are described

Basic/Prepared Explosives

• Service explosives include basic explosives with normal packing
• “Prepared charges”/“shaped charges designed for specific tasks as:
  • Beehives: blow bore holes
  • Hay rocks: cut reinforced concrete beams
  • Bangalore Torpedos: breach wire obstacles
• Apart from the Bangalore Torpedo, charges of this kind, together with specialist equipment like camouflet are written about in an arms pamphlet

Tetryl CE

• A high explosive from the coaltar group which is pale yellow
• Supplied as molded primers, wrapped in waterproof paper
• Mainly used as a primer in demolition
• Tetryl is moderately sensitive and can be set off by detonator
• They are affected slowly by moisture
• These keep well in hot climates and do not freeze

CE TNT Slab

• Yellow high explosive coming in 0.45kg rectangular slabs
• Each slab measures 11.43x6.35x4.45cm (4.5x2.25x1.75 inches) and are sealed in containers
• These are issued in a yellow colour and come in rectangular slabs. Slabs weigh 0.45kg each
• Slabs come with a 1cm primer
• Each box has 14 slabs that keep for long periods of time

PETN/TNT Pentolite

• A high explosive from coaltar that is pale yellow
• Available in casted nature for cutting and shaping
• Requires a primer in addition to a detonator to set off
• Keeps well in high temperatures and does not freeze

RDX/TNT

• Belongs to the coaltar group of explosives supplied in casted slabs or yellow blocks
• Normally detonated by using primer and detonator but in emergency detonator may be used
• Possesses good keeping properties in hot environments
• Insensitive to shock
• Is mainly used for cutting and shaped demolition

PP Plastic

• Black cartridge weighing 232 grams and sitting at 20.38cm
• Cartridge constitutes 80% RDX and 12% plasticizer in a waxed wrapper
• Loses plasticity under 32 degrees fahrenheit, but isn’t affected by hot ones
• Each case has 4 cartons of 2.3kg each

Bangalore Torpedo

• A prepared charge for breaching wire obstacles for infantry
• Is 3.81cm in dimension, Mark 1
• Filled with HE, in 1.83m sections weighing 6.36kg
• Sections have male and female ends, spring clip joints, and built-in primer
• It can construct gaps (Creates a gap of 3m) through obstacles

Improvised Charges

• Anti-tank mines, bombs, and shells can be used sans explosives
• They are inefficient; they need special initiation methods because of shape

Demolition Accessories List

• General requirements
• Crimpers: attach ignitors
• Igniters Safety Fuze Percussion: brass igniters
• Safety Fuze: initiates No 27 detonator

Safety Fuze Details

• For use to initiate a No. 27 detonator and add delay time
• Standard fuse, that comes 2x lengths of 7m in a cylinder
• Fuse burns at a rate of 0.6 NI, approximately, with a variation 2 feet per minute ± 6 seconds)
• cannot be used with other charges to create simultaneous initiation
• Absorbs moisture and will only burn at constant rate where powder is consistent

Safety Fuse Precautious

• First, cut the first 30cm off of the roll
• In addition, cut next 30cm off a part used roll to find a rate when not more than 33 seconds and not less than 27 seconds
• Also, should use above 45cm when detonating
• Any not for use in the immediate timeframe of 1.52m or less should be discarded to stock, though may be returned as dry stock
• Cut it clean, with the right tool
• Do not prep fuze, until that moment and keep armed
• In dire circumstances can use match, though igniter is standard

Detonator Details

• Used with safety fuze
• to initiate primers or cord
• Consists of a closed at one end metal tube and with
• designed to be initiated with safety fuze or fuze instantaneous
• rectifier inside tin and designed to increase axial hole in the guncotton primers.
• discouraged-if if detonation will not transpire destroys the acetone protection, before hand

detonator prep

• Cut with cleaner/squared ends
• Before crimping into wire/igniter - do not screw/damage to end
• Failures occur due to dust, don't poke

Primers

• Because of their comparative insensitivity, the current service explosives require a more sensitive charge to initiate them
• known as the primer, and itself requires initiation by means of a detonator or detonating cord

detonating cord and initiation practices

• approximately.64 centimetres with w/ HP
• used to simultaneously charge
• won't burn, it detonates ~5945-7960 m/sec
• though coated w/ WP
• render inert by damp

cord safety issues

• won't penetrate pass 30 c., leave space when using
• treat it with high explosive levels of safety
• cannot use match / high temp, must use other method
• double is good/ double the primer is ideal, at minimum however

Imitation

Faze Sealing

• For training purposes, imitate as best as possible, live and imitation cord
• Tube seals small ends
• Instant Fuze: w gunpowder, do not insert unless strip
• Striking Fure: brass cap ensures light
• Match version is more dangerous

Mark 2 Exploder Dynamos

• Rectangle, Bakelite w/ terminal
• When order, good ohms

Handling Exploders

• Read instructions on device
• fully charged is lethal!
• Cord first!
• Electrical Detonators require power

Detonator 33 Electrics

• Based on non electrics

Shock Wave Direction

• wave through curved direction.
• Force in travels directly direction.
• Changes direction is very smooth.
• Start points needs to point.

Individual Charge Assembly

• Point can be pressed into a charge
• slab with hole easy
• No problem

Detonator Cautions

General Improvised Charges

• Anti-Tank mines are unsafe - as bad as using old mines

Bombs

• Best is use "blast"
• Do not do air unexploded-distinguished by cylinder.

Table 3 - Bombs

• Fill fuze spot
• Fill with primer on top
• Insert charge within.

Detonating cords

• Main Lead
• taped at Clove

Hastey Circuits

In mines, Shells

Ring circuits

Multiple Charge Initiation

• Single limits
• Excavate gunpits and build fortifications

General electricals

• Electrics is a mine Pamphlet

Dangers Safety

To avoid failures, notes

Safey Fuze Notes

Dam Safety

Current Initatlum

Staff safety notes

• Demolitions often fail; misuse is due to the cord
• Bad training, not carefully following orders leads to mistakes.
• Have two sets ready
• discard 12 inches before use!

Quick Safety List

• Burn samples when outside normal
• No fuze.
• Crimp hard
• Shapr turn

Dampness

• Cover it with care
• HE is more stable
• Use CF

Table IY- Faults and Prevention

• Cut 15cm off and use

CHAPTER TARGET AND ATTACK

• Improvised Chargers

Guns Notes

• Take the Breech

Block for Tamping

• Block with good
• Prepare explosion lead

Other Weapons

• For small guns, need earth. Can use explosive to make good

Armour

• 9.Kilogram

Fuel Tank

• Pierced.

Vehicle Tips

• For wheel based vehicles, be sure wreck rad, and case cylinder and axle

Ground Emplacements and Explosives

Use of explosives

• Use exploes for ground pit
• Must clear as well.
• Mark Charge
• Center and use rule
• Then, clear, repeat and repeat

CHAPTER Safety

• Follow protocol

General precautions

• In Ops, use Officer to give clearance

Supervision

• Live exercise - give supervision , officer
• Supervised - given officer place for Jco

Danger Note

• Follow posted signs

Table V -Part I

• Use appropriate charge

Table 3 -

Distance from which varies

Use precautions before the activity

• Inspect lines

Table

Safely and operation in chart

Basic is as follow:

The General Notes

• No one goes to charge for thirty - to assess and reblast. Follow protocol.

Basic Tips

• Take 3 NCOs for any failures
• Never dump charges.
• Follow procedure . Keep clear . Listen • Mark. - No mess* Clear. Seek

Safety

• All stuff is "live!" Never mix. Learn "drill". Good habits

• Cord may be imitation or real. See notes for difference