Excavation Chapter 3

Explosive Product Formulation

Achieve: ______
maximize _______
minimize ________

Must have enough _____ to _____

Must have enough ____ to _____

Principal reacting ingredients:(4)

Fuel: reacts with ____
(1+4)

Oxidizers: yield ____ to ____
(1+3)

Sensitizers:
promote_______ and ______ of
detonation reaction (2 + 4)

Other (Principal reacting agents)
(2+2+3)

Gelling agents:
Flame retardant:
Antacids:

Dynamites

Dynamites which are nitroglycerin based explosives are often called ___ dynamites.

Originally they were made of pure nitroglycerin absorbed in _____ or _____.

NG is a blend of two organic _______ ____ namely ______ and _____.


In today’s NG dynamites the proportion of ______ is less than _____, which lowers the freezing point, provides better heat stability and It is cheaper.

They also contain nitrocellulose, oxidizing salts and fuels.

Sub-classifications of dynamites (2)

Granular dynamite (4)

Straight dynamite (no ammonium nitrate)
made of NG, sodium nitrate (oxygen balance), wood pulp (absorb NG) and carbonaceous fuels

___ detonation velocities
____ shattering effect
___ detonation temperature
____ sensitivity
_____ flammability
___ water resistance
____ class 3

_____ for underground, used
mainly for ditching application

High density ammonia dynamite (extra dynamite)

High density ammonia dynamites are the most widely used cartridged high explosive.

They have the same composition as straight dynamites except some of the nitroglycerin and sodium nitrate is replaced by ammonium nitrate

____ density
_____ velocity of detonation
____ borehole pressure
____ heaving action
_______ water resistance
______ fume characteristics

_____ for dry blasting in relatively soft grounds.

Low density ammonia dynamite:
Similar in composition to the high density products except more ____ and____ is replaced with ______. ____ strength, useful in ___ rocks.

Granular permissible
Same as ammonia dynamites except ___ is added.

Gelatin Dynamites

Blasting Gelatin

Mixture of ___% ___ and __% ___to form a rubbery cohesive gel.

— They are considered _____.
— Have the ____ detonating velocities.
— Emits large volumes of ______.
— Very ______

Most powerful of all NG based explosives.

Straight gelatin (gelatin dynamite) up to __% ___

Same as blasting gelatin except_____ and
_______ and sometimes _____ is added.

Improved ___
High ____
_______
Fume class - _____ in _____, _____ in ____
High ______ when _____

Ammonia gelatin: also called special gelatin or gelatin extra

It is a straight gelatin in which ____ and ____ is partly replaced with _______.

Improved _____
Improved _______
Improves _______
Good ________
High ______
High ______

Good for underground work.

The higher strengths can be used as primer.

Semi-gelatin

They are similar to ammonia gelatin except that more of the __,____ and ____ is replaced by ___ .

They combine the economy of ammonia dynamites with the strength and some of the water resistance of ammonia gelatin.

They are ____ water resistant than ammonia gelatins and ____ economical.
They are ___ water resistant than the ammonia dynamites.

_____ densities
_____ velocities
Often used under ___ conditions and sometimes as primers for _____.

Permissible gelatin

Ammonia gelatin or semi-gelatin with ____ added.

Nitro-Starch Explosives

Non-headache producing high explosives. All of the ___ is replaced by _____. No ____ sensitizer.

Do not ____.
Do not ____.
______________________.

Blasting Agents

An explosive products that meets prescribed criteria for ______ to _____ .

Blasting Agents (4)

Dry Blasting Agents (5)

Dry Blasting Agents

No ____ added.

______ is synonymous with dry blasting agent

Most common of all industrial explosives, in excess of __% of use.

ANFO is a mixture of ____ and _____.

Ideal mixture
___% Ammonium nitrate (AN)
___% Fuel oil (FO)

Must be oxygen balanced for ________.

Zero oxygen balance is the point at which an explosive mixture has sufficient ____ to completely ______ all the _____ but have no excess _____ to react with the contained _____.

At zero oxygen balance all gases are ____ and consist of ___, ____ and ____.

94.3% AN - 5.7% FO (oxygen balanced)
3 NH₄NO₃ + CH₂--> 7 H₂0 + CO₂ + 3N₂ + 904 kcal / kg

92.0% AN - 8.0% FO (fuel excess) not enough oxygen
2 NH₄N0₃ + CH₂ --> 5H₂O + CO + 2N₂ + 810 kcal/kg

96.6% AN - 3.4% FO (fuel shortage) excess oxygen
5 NH₄NO₃ + CH₂ —> 11 H₂O + CO₂ + 4 N₂ + 2 NO + 600 kcal / kg

formation of CO and NO is ____(___ ___)

It is generally better to ___ ___ ANFO rather than ____ ____ it.

Ammonium Nitrate Prills

Prills are porous, spherical shaped pellets typically between _____ mesh U.S. standard screen size.

Manufactured by concentrating an ammonium nitrate solution to ___-___%, then _____it. Removal of the moisture during the process produce voids this porosity is carefully controlled.

Prills are also coated to add certain amount of ______ to prevent caking and allow free flow

ANFO is the _____ of all explosives and ___ to manufacture. Generally it is _____ and ______ .

It is hard to give exact characteristics of ANFO. They will vary with: (7)

Properties of ANFO

In general ANFO has the following properties:

___ weight strength
___ bulk strength
___ detonation velocity
___ detonation pressure
___ gas production
___ borehole pressure
___ Heaving action
___ to handle, transport and store
Relatively ____
___ to manufacture
Bulk mixing on site and direct borehole loading, makes it ___ and ___ _ ___

Problems with ANFO:

___ of fuel oil by ____ or ____ can
result in the generation of _____ quantities of fumes

can react with some _____ (i.e. ___)

not ___ ______

must be ___ _____

____ primed for full efficiency

no ________ in bulk form

Bulk ANFO

Blown (pneumatic) or augered from bulk trucks, can be _____

Bagged ANFO

_____ resistant
____ pressure reduced

Aluminized ANFO

finely divided aluminum for ____ energy

81.6% AN - 18.4% Al

3 NH₄NO₃ + 2Al -> 6 H₂0 + AL₂O₃ + 3N₂ + 1975 kcal/kg

87.6% AN - 2.5% FO - 9.9% AI
6NH₄NO₃ + CH₂+ 2Al --> 13 H₂O + AL₂O₃ + 6 N₂ + CO₂ + 1320 kcal/kg

Cartridged ANFO

______ by crushing __% of ____ or adding ____ compounds.

Heavy ANFO

Mixture of ANFO> __% and ___(in varying %)
Full range of __ depending on %
Varying degree of _______ depending on %
Density between ___ and ___
Weight strength __ than ANFO
Bulk strength between ___and ___ compared to ANFO of ___

Low Density ANFO

For _____ blasting near ____structures, or blasting ____, _____ jointed or ___ density rocks which requires _____ shock energy a ___ concentration of energy is needed.

ANFO diluted with _____ can be used.
The product is often called ___ or ____.
Size distribution of the polystyrene is _____ the prill.
As low as __% prill by volume can be used
Densities as low as __ or __ can be achieved
_____ based oil is used as fuel
Packaged or bulk with tackifying agent to prevent ______

ANFO Emulsion Blends

ANFO is added to some emulsion explosives to ____ their physical characteristics and ___ the rate of detonation.

As prill concentration ___the water resistance ______

Common blends contain between __ to __% prill

Weight strength between __ to __ compared to ANFO at 100

Densities between __ to __ corresponding to a bulk strength of between ___ and ____.

Water gels or Slurries

They are gelled water-based explosives.

The continuous phase consists of _____ dissolved in water with ____ ingredients suspended by a ____

Requires ____ to ____.

Watergels or Slurries

Oxidizer salts
-ammonium nitrate
-sodium nitrate

Fuel

Sensitizer
- TNT, smokeless powder, nitrostarch, ethylene glycol mononitrate(EGMN), methylamine nitrate, ethanolamine nitrate.
- Al, air bubbles, monometholamine, micro-balloon or micro-spheres

Water 10-30%

Gums, waxes

Thickener

Gelling agents (crosslinkers)

Watergel Characteristics

Relatively _____ compared to ANFO
________ in full concentration
Can be __ or ______
Densities between __ and ___
Weight strength ____ ANFO
Bulk strength_____ as/than ANFO
VOD ___ than ANFO for similar charge diameter and confinement

Emulsions

Emulsions are prepared in the form of ____-in-___ emulsions

The ____ phase is composed of a solution of oxidizer salts suspended as microscopically fine droplets surrounded by a continuous fuel phase

The mixture is ____ against liquid separation by an _______

Composition of Emulsions

_____ Phase
.__________


______ Phase
. _______________
. ______________

________ Agents

______ Agents for density and sensitivity control
. _________
. _________
. _________
. _________

Properties of Emulsions

___ detonation velocities
. due to extremely ___ particle size
. if Al is added VOD _____
. VOD ___ with ___ in charge diameter
Densities from __ to __
____ detonation pressure
____ water resistance
____ over wide range of temperatures (200-900F)
Used for hard ____, ____, ____ for _____

Matching Explosives Shock and Heave to Blasting Requirements:

degree of existing fracturing and in-situ block sizes which control the degree of new breakage required

where significant breakage is needed, rock strength and breakage characteristics control the type and amount of explosive energy required

the dynamic properties of the rock mass, which controls the ease with which the rock transmits or absorbs dynamic strain energy

the stiffness or degree of brittleness as opposed to the plasticity of the rock mass which influence its fracture and displacement behavior

the porosity and density of the rock mass controls the interaction with

the explosive gases and the time required for burden movement