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rinciples of thermochemistry are applied for this process.

Thermochemistry is concerned with the changes in internal energy, principally asheat, in chemical reactions. An explosion consists of a series of reactions, highly exothermic, involving decomposition of the ingredients and recombination toform the products of explosion. Energy changes in explosive reactions are calculated either from known chemical laws or by analysis of the products.

For most common reactions, tables based on previous investigations permit rapidcalculation of energy changes. Products of an explosive remaining in a closed calorimetric bomb (a constant-volume explosion) after cooling the bomb back to room temperature and pressure are rarely those present at the instant of maximum temperature and pressure. Since only the final products may be analyzed conveniently, indirect or theoretical methods are often used to determine the maximum temperature and pressure values.

Some of the important characteristics of an explosive that can be determined bysuch theoretical computations are:

Oxygen balanceHeat of explosion or reactionVolume of products of explosionPotential of the explosive

Balancing chemical explosion equationsIn order to assist in balancing chemical equations, an order of priorities is presented in table 1. Explosives containing C, H, O, and N and/or a metal will form the products of reaction in the priority sequence shown. Some observation youmight want to make as you balance an equation:

The progression is from top to bottom; youmay skip steps that are not applicable, but you never back up.At each separate step there are never more than two compositions and two pro

ducts.At the conclusion of the balancing, elemental nitrogen, oxygen, and hydrogen

are always found in diatomic form.

Table 1. Order of Priorities Priority Composition of explosive Productsof decomposition Phase of products1

A metal and chlorine Metallic chlorideSolid2

Hydrogen and chlorine HClGas3

A metal and oxygen Metallic oxideSolid4

Carbon and oxygen COGas5

Hydrogen and oxygen H2OGas6

Carbon monoxide and oxygen CO2Gas7

Nitrogen N2

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Gas8

Excess oxygen O2Gas9

Excess hydrogen H2Gas10

Excess carbon CSolid

Example, TNT:

C6H2(NO2)3CH3; : 7C + 5H + 3N + 6O

Using the order of priorities in table 1, priority 4 gives the first reaction products:

7C + 6O 6CO with one mol of carbon remaining

Next, since all the oxygen has been combined with the carbon to form CO, priority 7 results in:

3N 1.5N2

Finally, priority 9 results in: 5H 2.5H2

The balanced equation, showing the products of reaction resulting from the detonation of TNT is:

C6H2(NO2)3CH3 6CO + 2.5H2 + 1.5N2 + C

Notice that partial moles are permitted in these calculations. The number of moles of gas formed is 10. The product carbon is a solid.Example of thermochemical calculations

The PETN reaction will be examined as an example of thermo-chemical calculations

.PETN: C(CH2ONO2)4Molecular weight = 316.15 g/molHeat of formation = 119.4 kcal/mol

(1) Balance the chemical reaction equation. Using table 1, priority 4 gives thefirst reaction products:

5C + 12O 5CO + 7O

Next, the hydrogen combines with remaining oxygen:

8H + 7O 4H2O + 3O

Then the remaining oxygen will combine with the CO to form CO and CO2.

5CO + 3O 2CO + 3CO2

Finally the remaining nitrogen forms in its natural state (N2).

4N 2N2

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The balanced reaction equation is:

C(CH2ONO2)4 2CO + 4H2O + 3CO2 + 2N2

(2) Determine the number of molar volumes of gas per mole. Since the molar volume of one gas is equal to the molar volume of any other gas, and since all the products of the PETN reaction are gaseous, the resulting number of molar volumes of gas (Nm) is:

Nm = 2 + 4 + 3 + 2 = 11 Vmolar/mol

(3) Determine the potential (capacity for doing work). If the total heat liberated by an explosive under constant volume conditions (Qm) is converted to the equivalent work units, the result is the potential of that explosive.

The heat liberated at constant volume (Qmv) is equivalent to the heat liberatedat constant pressure (Qmp) plus that heat converted to work in expanding the surrounding medium. Hence, Qmv = Qmp + work (converted).

a. Qmp = Qfi (products) Qfk (reactants)

where: Qf = heat of formation (see table 1)

For the PETN reaction:

Qmp = 2(26.343) + 4(57.81) + 3(94.39) (119.4) = 447.87 kcal/mol

(If the compound produced a metallic oxide, that heat of formation wouldbe included in Qmp.)

b. Work = 0.572Nm = 0.572(11) = 6.292 kcal/mol

As previously stated, Qmv converted to equivalent work units is taken as thepotential of the explosive.

c. Potential J = Qmv (4.185 106 kg)(MW) = 454.16 (4.185 106) 316.15 = 6.01 106 J kg

This product may then be used to find the relative strength (RS) of PETN, which is

d. RS = Pot (PETN) = 6.01 106 = 2.21 Pot (TNT) 2.72 106 The Many Uses of Explosives

Many people know that explosives are used in Mining, Building Demolition, Pyrotechnics and even Construction. Many would be surprised to know about some of theunusual uses of explosives. Did you know that explosives were used to carve Mount Rushmore? Explosives are also used to control Avalanches and are used in the backcountry for Trail Maintenance. Explosives are even used in Medicine to break-up kidney stones!

In the United States, explosives are primarily used in Mining, Quarrying and Construction as shown below:

Nationwide explosive use:Coal Mining 67%Non-metal mines and quarries 14%Metal mining 10%Construction 7% andMiscellaneous 3%

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The Many Uses of Explosives:

Aerospace - As in Ejector Seats and Separation Devices for Rocket Boosters

Agriculture - Farmers use explosives to break up boulders, blow tree stumps, felling trees and loosening soil.

Aggregate Blasting Art - As in Metalclad art and large projects such asMountaincarving

Automotive Restraint Systems - to inflat Airbags

Avalanche ControlAvalanche Control

Coal Blasting Commercial and Industrial Products - Door Systems, for example

Construction

Demilitarization Work

ImplosionDemolition - The quantities of explosive used on this type of operation vary, depending on the size, construction and location, of the structure to be demolishe

d. Whether it be Bridges, Buildings, Chimneys, or Towers.Diamond Manufacturing - Jewelry grade and Very fine industrial-type diamonds used for grinding and polishing are produced by the carefully controlled action ofexplosives on carbon.

Emergencies at Sea - project lifelines to ships in distress off storm-beaten shores

Excavation - to dig Foundations and clear Underwater Channels/Dredging

Fire Fighting - Along fire paths to cut off oxygen to a large fire and to extinguish oil well fires.

Fire Suppression Systems

Fireworks (See Pyrotechnics)

Food Preparation - Meat Tenderizing

Forestry - Trail Blazing

Hazardous Wastes - for destruction of some hazardous waste materials

Ice Jams

Law Enforcement and Security - used in Exploding Dye Capsules and other SecuritySystems.

Logging - For cutting and removing timber

Manufacturing - Man-made diamonds

Medical Uses Medicines / Fracturing Kidney and Gall Stones

Metalworking - Hardening of Metals - Including railway frogs and hardening of cr

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usher wear parts, shovel teeth, ripper shanks, and speciality wear components such as striker bars and striker plates for mills. The explosive depth hardening process will take manganese steel from 350 brinell up to 490 brinell after two shots. The EDH process increases wear life substantially.

Metal-cladding - Explosives are sometimes used to bond various metals to each other.

Mining and Quarrying - Explosives are used to break up rock and displace large quantities of earth.

Nail guns

Oil Well Perforation

Pile driving - When pile drivers are not available, exploding dynamite on an iron plate placed on top of the piles can do their work.

Pyrotechnics - Display fireworks / Theatrical Special Effects

Quarrying

Railroads - Hardening and removing track parts

Riveting - Blind rivets are needed when space limitations make conventional rivets impractical. Explosive riveting is an engineering practice.

Rocketry

Seismic Exploration

Signal Lights

Soil Compaction - For large-scale construction projects, soil compaction is often accomplished with the use of explosives.

Sport Shooting - Gunpowder (blackpowder and smokeless powder) is used for shooti

ng purposes, such as muzzle-loading handguns and rifles, or events where re-enactments of historical battles involve the use of muzzle-loading muskets and cannon.

Tools - Hand tools

Tunneling

Welding - Explosives jigs are often used to weld large diameter Pipelines.History of Explosives and Blasting

In the US and Canada alone, blasters use more than 6 billion pounds of explosives and 75 million detonators per year. Coal mining accounts for two-thirds of con

sumed explosives of which more than 80% of it is ANFO.

Today, sophisticated explosive materials and new technologies are being utilizedto improve the quality of life for all of us. Computers are used to: drill, logand monitor blastholes automate blending and delivery with bulk trucks determine bench heights and face conditions analyze production efficiency, design blastpatterns and more.

The time line below presents the history of the explosives industry... a tradition of excellence in mining, quarrying, construction, and many other pursuits inv

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olving the peaceful use of explosives to break rock in service to mankind.50 B.C.

Early form of seismoscope used by Chang Heng in China.668 A.D.

"Greek-fire" used in battle.1200 A.D.

Arabian author Abd Allah records use of saltpeter as main ingredient of black powder.13th Centur

yChinese use "Roman Candles" in seige of Kai-Feng Fu.1242

English Friar Roger Bacon publishes gunpowder formula.1380

German Franciscan Monk, Berthold Schwarts developed gunpowder and its use in guns.

German Franciscan Friar Sebastian Munster

Berthold SchwartsGerman Franciscan Monk1627

First recorded use of black powder for rock blasting (Hungary).1670

Black powder use spreads to tin mines of Cornwall England by German miners.1675

First powder mill in U.S. constructed in Milton, Mass.1696

First recorded use of black powder for road construction in Switzerland.1745

Doctor Watson of British Royal Society explodes black powder with an electric spark.1749

Hungarian Miners introduce chisel bit.1750

American inventor Benjamin Franklin encases and compresses powder in cartridges.1773

Black powder first used in U.S. at Copper Mine in Connecticut.1785

Machine to detect earthquake vibrations invented.1818-1821

First use of black powder in construction of road tunnel in Pennsylvania.1830

Moses Shaw of New York patents electric firing of black powder.

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1831

William Bickford of Cornwall, England invents Safety Fuse.1832

Dr. Robert Hare of University of Pennsylvania demonstrates bridge wire electricblasting cap.1841

Milne invents "Seismometer" to detect ground vibrations by earthquakes.1846

Italian chemist Ascanio Sobrero discovers nitroglycerine.1849

Jonathan Couch patents first practical American percussion-style steam powered rock drill.1861

First practical use of piston-type compressed air mechanical drill in 8-mile long Mount Cenis Tunnel in the Alps.1863

Wilbrand invents Trinitrotoluene (TNT).

1864Swedish inventor Alfred Nobel develops first detonating blasting cap.

Alfred Nobel

Alfred NobelThe Father of Explosives1866

Swedish chemist Alfred Nobel invents dynamite by mixing kieselguhr with nitroglycerine.1866

First U.S. plant to make nitroglycerine, Little Ferry, NJ.1869

First use of diamond drills for prospecting and blasthole drilling.1870

First U.S. dynamite plant, Giant Powder Co., San Francisco, California.1871

Simon Ingersoll patents tripod mount for steam powered rock drill.1872

Gunpowder Trade Association formed in U.S.1875

Nobel patents blasting gelatine.1878

Rack bar electric blasting machine developed by H. Julius Smith.1884

Ammonium Nitrate (AN) becomes widely used in dynamite formulations.

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U.S. National Academy of Sciences studies Ammonium Nitrate (AN) after explosionin Oppau, Germany.1924

First use of seismograph for oil prospecting by Gulf Production.

Largest industrial blast to date in U.S. fired at California Blue Diamond quarryusing 328,000 lbs. of dynamite 1924.1926

Blasting cap safety education program launched by IMEMid 1920s

Liquid Oxygen based explosives commercialized in U.S.1927

History of Explosives Industry in America published by IME.1928

Detachable drill bits introduced at Anaconda Copper Mine, Butte, Montana.1930

U.S. Bureau of Mines forms geophysical section headed by Dr. F. Lee.

Early 1930sJackleg drill introduced.1931

Fiberboard cases approved for dynamite shipping.1933

Roller cone bits introduced in oil fields.1935

U.S. Geological Survey develops blast vibration machine cost $25,000.1935

duPont introduces first commercially successful non-nitroglycerin ammonium nitrate (AN) blasting agent.1936

IME establishes fume classes for explosives in underground mines.1938

Modern PETN-filled fabric-covered detonating cord introduced in U.S.1939

U.S. Bureau of Mines begins work on vibration standards.

Modern plastic explosives invented during WWII.1940s

Self propelled open pit rock drills introduced.

Use of tungsten carbide bits began in mining in Sweden.1946

Short interval millisecond delay electric blasting caps introduced.1947

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Industry assists with federal investigation of Texas City, Texas Ammonium Nitrate explosion.1948

Pennsylvania issues regulations limiting blast vibrations.

First shot on Crazy Horse monument South Dakota.

U.S. production of ammonium nitrate (AN) for fertilizer totally converted to prilling method.

Crazy Horse Memorial

Crazy Horse Memorial - 20031950

First portable 3 component monitor developed, the Leet Seismograph weighs 65 lbs.

Seismograph

Leet Seismograph1952

New Jersey issues regulations on seismic effects and airblast.1955

Maumee Collieriers Drilling & Blasting Superintendent Bob Akre introduces "Akremite" at Coal Show in Cleveland, Ohio.1955

Down hole drill introduced using high-pressure portable air compressors.1956

First use of ANFO by U.S. Steel Corp.s OliverMining Division.

Dr. Mel Cook introduces Slurry to mining.1957

Underground explosives consumption reaches 100million pounds in the United States.

First bulk vehicles blow mixed ANFO down-the-hole at Iron Ore Co. of Canada.1959

Roseberg, Oregon fire and explosives truck explosion (Download Full Story).

August 7, 1959Roseburg, Oregon

Thirty-nine dynamite plants operating in the United States.1950s.

High-speed photography for blast analysis introduced.Late 1950s

Prilled AN fuel mixture begins to replace dynamite.

Bulk trucks and loaders developed.1960s

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Tunnel boring machines begin to seriously impact the use of explosives in largetunnel jobs.1964

Dromedary trucks used to haul explosives approved by US ICC.1967

Shock tube-type non-electric delay detonators introduced in Sweden.1969

Emulsion explosives introduced.1960s & 70s

Large rotary drills with drag bits and roller cone bits come into use.1971

Emulsion ANFO blends introduced.1972

Lang & Favreau introduce Computer Modeling of Blast Design.1973

Electronic sequential blasting introduced at first Kentucky Blasters Conference.

Largest pre-production shot to date - 4 million pounds at Old ReliableMine in Arizona.1970s

Hydraulic powered drifter drills come into use.Early 1970s.

First electronic recording seismographs developed by Dallas Instruments.1974

British Institute of Explosives Engineering established.

Shock tube-type non-electric delay detonators introduced in U.S.The Society of Explosives Engineers officially formed to "advance the art and science of explosives engineering" on August 20, 1974 in Pittsburgh, Pennsylvania.1977

First commercial use of glass "bubbles."1978

OSMR created under U.S. Dept of Interior. MSHA created under Dept of Labor.

J. Wiss & P. Lineham complete research on controlling vibrations through shot design for USBM.

Twenty-six story hotel, tallest steel structure demolished to date using explosives, Oklahoma City.1979

IME member and S.E.E. Director Deane Boddorff demonstrate easy removal of taggants from dynamite for U.S. Senate Committee.1980

Bulk Blends introduced.

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Dr. Per-Anders Persson of Sweden, inventor of the Nonel (non-electric) blastingsystem, receives Society of Explosives Engineers first Distinguished Service Award.1980s

Digital sampling seismographs developed.

Drill monitoring equipment first used.

Commercial use of computers to improve blast timing patterns and blast shot plans introduced.1985

Society of Explosives Engineers members assist with rescue and clean-up effortsafter 5,000 die in Mexico City earthquake. (Download Full Story)

September 20, 1985Mexico City, Mexico1987

Largest underground shot in Western Europe 628,000 pounds shot in Ireland.1988

Laser profiling for blast design and analysis, developed in Britain, introducedin the United States.1989

Society of Explosives Engineers assists Congressional Committee with investigation of USS Iowa explosion.Late-1980s

Electronic delay detonators (EDDs) introduced.1991

Industry works with USDOT to adopt HM 181, UN classifications for explosives packaging.

1992Explosives used to extinguish most of 700 Kuwaiti oil well fires after Gulf War.1990s

Use of automated drilling, GPS hole spotting and PLC operated drills for surfacemining.1994

Society of Explosives Engineers Education Foundation formed.

First Annual Golf Outing in memory of former member Jerry McDowell raises fundsfor SEE Education Foundation scholarships.

1995

One dynamite plant still operating in the United States.

Australias largest shot ever, 1.25 million pounds of explosives at Ord River project.

U.S. Bureau of Mines dismantled despite strong industry and ISEE support.1996

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ISEE goes online at www.isee.org/

IME video released, Explosives: The Power Tool, cosponsored by ISEE andNobel Insurance.1998

Virginia Polytechnic and University of Missouri-Rolla are the first student chapters chartered by ISEE.

International Society of Explosives Engineers (ISEE) celebrates 25th Annual Conference and 25 years of service to the explosives industry.2001

ISEE members assist with World Trade Center clean-up efforts.

ISEE members assist in anti-terrorism efforts in Afghanistan.2004

Public Education Committee of ISEE releases DVD "Understanding Vibrations from BlastingHow Explosives Work

Explosives are chemicals and, like all chemicals, should be treated safely and with respect.

Unlike other chemicals, most explosives detonate rather than burn. A detonationis a very rapid chemical reaction using oxygen that is contained in thematerialrather than in the air. In a detonation, the chemical reaction releases gases that rapidly expand and give off energy as they become hot.Two Basic Types

Explosives are categorized into two basic types, low explosives and high explosives. Low explosives tend to deflagrate, rather than detonate, which means that they burn at a slower rate and create less pressure than high explosives. Low explosives are often used as propellants to force a bullet out of a gun or send a rocket into space.Low Explosives

For many years, black powder was the most common low explosive used throughout the world. But black powder, or gun powder as it was commonly called, produced alarge amount of smoke and was dangerous to use. Today black powder is still usedfor pyrotechnics (fireworks), special effects, and other specialized work, butit has been replaced in commercial blasting by safer, more productive explosivematerials.High Explosives

High explosives createmore pressure and burnmore quickly, detonating almost instantaneously. The proper use of high explosives by todays explosives engineer, produces minimal ground vibrations and air overpressure.

The first high explosive used in commercial blasting was nitroglycerine, also called "blasting oil." Nitroglycerine was dangerous to use because it is an unstable chemical. But in the late 1800s, a Swedish chemist, named Alfred Nobel, invented dynamite by mixing nitroglycerine with a special clay, called kieselghur, andpacked it into sticks.

Dynamite became the first safe high explosive used. It can be dropped, hit witha hammer or even burned and will not accidentally explode. There are a number ofdifferent types of dynamites being used today, all containing nitroglycerine.How Explosives Have Shaped Our World

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Few people today givemuch thought to the role that explosives play in their lives each day and how they are linked to our standard of living and our very way of life. Explosives provide the means to free up the vast resources of the earthfor the advancement of civilization.Our Standard of Living

In order to maintain our standard of living in the United States, every day 187,000 tons of cement aremixed, 35 million paper clips are purchased, 21million photographs are taken using millions of ounces of silver...80 pounds of gold areused to fill 500,000 cavities and 3.6 million light bulbs are purchased.

Few people know that 42 different minerals are used to make a telephone and 35 are used to make a color television. Even everyday products such as talcum powder, toothpaste, cosmetics and medicines containminerals, all of which must be mined using explosives.(http://www.smenet.org/gem/)

In fact it is difficult to think of any product that is not extracted from or improved upon through the use of explosives. The roadways we travel on and tunnelswe travel through are built by first breaking rock using explosives. The cars we travel in contain steel, copper, aluminum, and zinc all raw materials extracted from the ground using explosives. Our computers are built using gold, silver,copper and silica. Our power sources coal, fuel, natural gas pipelines, hydroele

ctric dams are extracted or built using the power of explosives.From the Beginning

During the very beginnings of this country, the explosives industry was foundedwhen black powder was used to extract minerals, break rock, clear fields and make roads. It is not an overstatement to say that the infrastructure of the UnitedStates was built with the help of explosives. In the 1860s, Alfred Nobel, a Swede, invented dynamite and the blasting cap required to make dynamite explode.

He licensed it in theUnited States and the industrial revolution began.

With the use of dynamite, mines could be dug deeper and more quickly, and mineral deposits that were uneconomical to mine became profitable. The mining of coppe

r, coal and iron ore increased a hundred fold. New industries began.Rock quarries delivered materials such as limestone, cement and concrete which became common building products, replacing bricks and cobblestones. Harbors weredeepened and widened, railways and roads expanded into the West and dams were built creating enough electricity to pave the way to the 20th Century.

Between the end of the Civil War and the end of World War II, no single engineering tool surpassed the achievement of dynamite. During the last four decades this workhorse of industrial progress has been joined by even more efficient and safer products such as watergels, emulsions and ANFO.

Today, we rely on explosives engineering more than ever in our quest for more el

ectrical energy, better roadways and more mineral harvesting.Safety FirstSafety First! Dont Touch

Blasting Caps are detonators. They contain a small amount of blasting powder andare designed to explode with tremendous force. Their purpose for trained operators is to set-off a larger explosive such as dynamite. Blasting caps are Labeled"Dangerous Blasting Cap Dont Touch."

If you find a blasting cap, DONT TOUCH! Call your local police or fire departmentimmediately to report it. In unskilled hands, blasting caps are deadly. They ca

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n mutilate fingers, cause blindness and deafness or kill!