Tovex
Encyclopedia
Tovex is a water-gel explosive composed of ammonium nitrate and methylammonium nitrate that has several advantages over traditional dynamite
, including lower toxicity and safer manufacture, transport, and storage. It has thus almost entirely replaced dynamite
.
There are numerous versions ranging from shearing
charges to aluminized
common blasting agent. Tovex is used by 80% of international oil
companies
for seismic exploration.
(E.I.du Pont de Nemours & Company, Inc.) in the mid-to-late 1960s when pelletized TNT was included in aqueous gels to create a slurry form of ANFO
that displayed water-resistant properties in wet bore holes. TNT sensitized water gels were commercially successful, yet the TNT led to problems with oxygen balance: namely elevated amounts of combustion by-products such as carbon monoxide and nitrogen-dioxide complexes. Not only was TNT "dirty," but it was also expensive. TNT was eliminated through the work of DuPont chemists Colin Dunglinson and William Lyerly and a team of others at DuPont's Potomac River Development Laboratory (PRDL) at Falling Waters, West Virginia, and at DuPont's Eastern Laboratories (EL) at Gibbstown, New Jersey. These chemists and engineers formulated a series of water gel-base products that replaced the TNT with methyl ammonium nitrate, also known as mono-methylamine nitrate, or PR-M, (which stands for "Potomac River – monomethylamine nitrate") creating the "Tovex" "Extra" product line.
In late 1973, DuPont declared "the last days of dynamite" and switched to the new Tovex. The "Tovex" (that replaced nitroglycerin-based dynamite) had evolved into a cap-sensitive product. Even though it bore the same name as the earlier "Tovex," it was quite different from the precursors which could only be initiated with a one pound TNT booster in large diameter (5-inches). The new Tovex of the mid-to-late 1970s could be detonated in (critical) diameters much smaller than 5-inches by utilizing DuPont's Detaflex, thus making the new Tovex a realistic replacement for dynamite.
Until then, only nitroglycerin based explosives were commercially feasible for blasters who wanted cap-sensitive explosives that could be initiated with a #6 blasting cap
in bore holes as small as 3/4 of an inch in diameter, sometimes less. The new Tovex satisfied that requirement.
Atlas, Hercules, IRECO, Trojan-US Powder and several other explosives manufacturing firms of the era created emulsions, gels and slurries which accomplished the same end, but it was the DuPont patent of PR-M based explosives that gave the DuPont Company a competitive edge.
DuPont Stopped producing nitroglycerine-based dynamite in 1976, replacing it with Tovex. In 1980, it sold its Tovex technology to Explosive Technology International (ETI), a Canadian company. One ETI licensee is Biafo Industries Limited, headquartered in Islamabad
, Pakistan
. Biafo's Web page notes that major customers are located in Iran, Bangladesh, Sri Lanka and Gulf States.
As of this writing, explosives sold under DuPont's original "Tovex" trade name are distributed in Europe
by Societe Suisse des Explosifs, Brigue, in Switzerland
.
of ammonium nitrate and methylammonium nitrate (sometimes also called mono methylamine nitrate, or PR-M), sensitized fuel
s and other ingredients including sodium nitrate prills, finely divided (paint-grade) aluminum, finely divided coal, and proprietary materials to make some grades cap
sensitive, and thickening agent
s to enhance water resistance and that act as crystal modifiers. The detonation velocity of Tovex is around 4,000 to 5,500 m·s−1
. The specific gravity
is 0.8–1.4. Tovex looks like a white to black fluid gel.
regions for avalanche
release.
For dead trees which are considered too hazardous to remove utilizing crosscut saw
s or chainsaws, one or two wraps of Tovex around the base of the tree is often enough to fell the tree safely so that the remains of the tree may be safely bucked and be removed from hiking trails, parks, and other places where people recreate.
For firebreak the product is simply uncoiled and laid along the ground to follow the ridge line or contours of the hillside or mountain along which the fire crews wish to establish a line of defense. Fire crews then follow-up the blasted line to clear debris to establish a fuel-free line.
For more technical blasting which requires greater planning and finesse, Tovex is often bundled according to weight in to or up against a solid material, then detonation cord is applied to the Tovex such that the cord creates a fast moving, heated dynamo effect within the Tovex when one or more blasting caps ignite the detonation cord, thus accelerating the Tovex which causes it to detonate.
Blasting caps are ignited utilizing hand-held intrinsically safe control boxes which employ a series of safety interlocks and switches which also employ a strict radio sessioning handshake protocol between the unit which ignites the cap, and the unit used by the Master Blaster
controlling the shot, ensuring that the emplaced Tovex, detonation cord, and caps can not ignite prematurely.
After detonation the material is completely utilized, there is no discernible residue unless one employs microscopic analysis. Typically Tovex and other commercial explosives employ embedded taggant
s which identify the product and often identify the agency which purchased the material.
Dynamite
Dynamite is an explosive material based on nitroglycerin, initially using diatomaceous earth , or another absorbent substance such as powdered shells, clay, sawdust, or wood pulp. Dynamites using organic materials such as sawdust are less stable and such use has been generally discontinued...
, including lower toxicity and safer manufacture, transport, and storage. It has thus almost entirely replaced dynamite
Dynamite
Dynamite is an explosive material based on nitroglycerin, initially using diatomaceous earth , or another absorbent substance such as powdered shells, clay, sawdust, or wood pulp. Dynamites using organic materials such as sawdust are less stable and such use has been generally discontinued...
.
There are numerous versions ranging from shearing
Shearing (physics)
Shearing in continuum mechanics refers to the occurrence of a shear strain, which is a deformation of a material substance in which parallel internal surfaces slide past one another. It is induced by a shear stress in the material...
charges to aluminized
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
common blasting agent. Tovex is used by 80% of international oil
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...
companies
Corporation
A corporation is created under the laws of a state as a separate legal entity that has privileges and liabilities that are distinct from those of its members. There are many different forms of corporations, most of which are used to conduct business. Early corporations were established by charter...
for seismic exploration.
History
The Tovex family of products, sometimes generically called "water gels," were developed by the old Explosives Department at DuPontDuPont
E. I. du Pont de Nemours and Company , commonly referred to as DuPont, is an American chemical company that was founded in July 1802 as a gunpowder mill by Eleuthère Irénée du Pont. DuPont was the world's third largest chemical company based on market capitalization and ninth based on revenue in 2009...
(E.I.du Pont de Nemours & Company, Inc.) in the mid-to-late 1960s when pelletized TNT was included in aqueous gels to create a slurry form of ANFO
ANFO
ANFO is a widely used bulk industrial explosive mixture. It consists of 94 percent porous prilled ammonium nitrate , that acts as the oxidizing agent and absorbent for the fuel — six percent Number 2 Fuel Oil...
that displayed water-resistant properties in wet bore holes. TNT sensitized water gels were commercially successful, yet the TNT led to problems with oxygen balance: namely elevated amounts of combustion by-products such as carbon monoxide and nitrogen-dioxide complexes. Not only was TNT "dirty," but it was also expensive. TNT was eliminated through the work of DuPont chemists Colin Dunglinson and William Lyerly and a team of others at DuPont's Potomac River Development Laboratory (PRDL) at Falling Waters, West Virginia, and at DuPont's Eastern Laboratories (EL) at Gibbstown, New Jersey. These chemists and engineers formulated a series of water gel-base products that replaced the TNT with methyl ammonium nitrate, also known as mono-methylamine nitrate, or PR-M, (which stands for "Potomac River – monomethylamine nitrate") creating the "Tovex" "Extra" product line.
In late 1973, DuPont declared "the last days of dynamite" and switched to the new Tovex. The "Tovex" (that replaced nitroglycerin-based dynamite) had evolved into a cap-sensitive product. Even though it bore the same name as the earlier "Tovex," it was quite different from the precursors which could only be initiated with a one pound TNT booster in large diameter (5-inches). The new Tovex of the mid-to-late 1970s could be detonated in (critical) diameters much smaller than 5-inches by utilizing DuPont's Detaflex, thus making the new Tovex a realistic replacement for dynamite.
Until then, only nitroglycerin based explosives were commercially feasible for blasters who wanted cap-sensitive explosives that could be initiated with a #6 blasting cap
Blasting cap
A blasting cap is a small sensitive primary explosive device generally used to detonate a larger, more powerful and less sensitive secondary explosive such as TNT, dynamite, or plastic explosive....
in bore holes as small as 3/4 of an inch in diameter, sometimes less. The new Tovex satisfied that requirement.
Atlas, Hercules, IRECO, Trojan-US Powder and several other explosives manufacturing firms of the era created emulsions, gels and slurries which accomplished the same end, but it was the DuPont patent of PR-M based explosives that gave the DuPont Company a competitive edge.
DuPont Stopped producing nitroglycerine-based dynamite in 1976, replacing it with Tovex. In 1980, it sold its Tovex technology to Explosive Technology International (ETI), a Canadian company. One ETI licensee is Biafo Industries Limited, headquartered in Islamabad
Islamabad
Islamabad is the capital of Pakistan and the tenth largest city in the country. Located within the Islamabad Capital Territory , the population of the city has grown from 100,000 in 1951 to 1.7 million in 2011...
, Pakistan
Pakistan
Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...
. Biafo's Web page notes that major customers are located in Iran, Bangladesh, Sri Lanka and Gulf States.
As of this writing, explosives sold under DuPont's original "Tovex" trade name are distributed in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
by Societe Suisse des Explosifs, Brigue, in Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
.
Properties
Tovex is a 50/50 aqueous solutionAqueous solution
An aqueous solution is a solution in which the solvent is water. It is usually shown in chemical equations by appending aq to the relevant formula, such as NaCl. The word aqueous means pertaining to, related to, similar to, or dissolved in water...
of ammonium nitrate and methylammonium nitrate (sometimes also called mono methylamine nitrate, or PR-M), sensitized fuel
Fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
s and other ingredients including sodium nitrate prills, finely divided (paint-grade) aluminum, finely divided coal, and proprietary materials to make some grades cap
Blasting cap
A blasting cap is a small sensitive primary explosive device generally used to detonate a larger, more powerful and less sensitive secondary explosive such as TNT, dynamite, or plastic explosive....
sensitive, and thickening agent
Thickening agent
Thickening agents, or thickeners, is the term applied to substances which increase the viscosity of a solution or liquid/solid mixture without substantially modifying its other properties; although most frequently applied to foods where the target property is taste, the term also is applicable to...
s to enhance water resistance and that act as crystal modifiers. The detonation velocity of Tovex is around 4,000 to 5,500 m·s−1
Metre per second
Metre per second is an SI derived unit of both speed and velocity , defined by distance in metres divided by time in seconds....
. The specific gravity
Specific gravity
Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...
is 0.8–1.4. Tovex looks like a white to black fluid gel.
Ingredients
- sodium nitrateSodium nitrateSodium nitrate is the chemical compound with the formula NaNO3. This salt, also known as Chile saltpeter or Peru saltpeter to distinguish it from ordinary saltpeter, potassium nitrate, is a white solid which is very soluble in water...
- ammonium nitrate
- methyl ammonium nitrateMethyl ammonium nitrateMethylammonium nitrate is an explosive chemical with the molecular formula CH6N2O3, alternately CH3NH3+NO3-. It is the salt formed by the neutralization of methylamine with nitric acid...
(sometimes called "Monomethylamine Nitrate") - calcium nitrateCalcium nitrateCalcium nitrate, also called Norgessalpeter , is the inorganic compound with the formula Ca2. This colourless salt absorbs moisture from the air and is commonly found as a tetrahydrate. It is mainly used as a component in fertilizers but is found other applications...
- aluminum
- fuel oilFuel oilFuel oil is a fraction obtained from petroleum distillation, either as a distillate or a residue. Broadly speaking, fuel oil is any liquid petroleum product that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, except oils having a flash...
No.2 - carbonaceousCarbonaceousCarbonaceous is the defining attribute of a substance rich in carbon. Particularly, carbonaceous hydrocarbons are very unsaturated, high-molecular-weight hydrocarbons, having an elevated carbon:hydrogen ratio....
Fuel - perlitePerlitePerlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently...
- silica (fibrous glass)
- ethylene glycolEthylene glycolEthylene glycol is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid...
- guar gumGuar gumGuar gum, also called guaran, is a galactomannan. It is primarily the ground endosperm of guar beans. The guar seeds are dehusked, milled and screened to obtain the guar gum. It is typically produced as a free-flowing, pale, off-white-colored, coarse to fine ground powder.-Production:Guar gum is an...
Uses
Tovex Avalanche is used in mountainMountain
Image:Himalaya_annotated.jpg|thumb|right|The Himalayan mountain range with Mount Everestrect 58 14 160 49 Chomo Lonzorect 200 28 335 52 Makalurect 378 24 566 45 Mount Everestrect 188 581 920 656 Tibetan Plateaurect 250 406 340 427 Rong River...
regions for avalanche
Avalanche
An avalanche is a sudden rapid flow of snow down a slope, occurring when either natural triggers or human activity causes a critical escalating transition from the slow equilibrium evolution of the snow pack. Typically occurring in mountainous terrain, an avalanche can mix air and water with the...
release.
- blasting for road construction
- miningMiningMining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
for mineralMineralA mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s - quarriesQuarriesQuarries - The "Royal Quarries" — not found in Scripture — is the namegiven to the vast caverns stretching far underneath the northern hill, Bezetha, on which Jerusalem is built. Out of these mammoth caverns stones, a hard limestone, have been quarried in ancient times for the buildings in the...
for the constructionConstructionIn the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...
and building industry - seismic explorationReflection seismologyReflection seismology is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. The method requires a controlled seismic source of energy, such as dynamite/Tovex, a specialized air gun or a...
- tunnelingTunnelingTunneling may refer to:* Digging tunnels * Quantum tunneling, the quantum-mechanical effect where a particle crosses through a classically-forbidden potential energy barrier...
- hiking trail building
- cutting fire lines
- hazardous tree removal
Sample applications
The blasting product is malleable to the point where it can be cut to length, laid out, or bundled for a wide variety of applications. Because the material requires heat and fast compression to detonate, it is safe to transport and manipulate once in the field, even if dropped from high altitude, set on fire, or peppered with high velocity rifle bullets.For dead trees which are considered too hazardous to remove utilizing crosscut saw
Crosscut saw
A crosscut saw is a saw that is specially designed for making crosscuts. A crosscut is a cut made horizontally through the trunk of a standing tree, but the term also applies to cutting free lumber...
s or chainsaws, one or two wraps of Tovex around the base of the tree is often enough to fell the tree safely so that the remains of the tree may be safely bucked and be removed from hiking trails, parks, and other places where people recreate.
For firebreak the product is simply uncoiled and laid along the ground to follow the ridge line or contours of the hillside or mountain along which the fire crews wish to establish a line of defense. Fire crews then follow-up the blasted line to clear debris to establish a fuel-free line.
For more technical blasting which requires greater planning and finesse, Tovex is often bundled according to weight in to or up against a solid material, then detonation cord is applied to the Tovex such that the cord creates a fast moving, heated dynamo effect within the Tovex when one or more blasting caps ignite the detonation cord, thus accelerating the Tovex which causes it to detonate.
Blasting caps are ignited utilizing hand-held intrinsically safe control boxes which employ a series of safety interlocks and switches which also employ a strict radio sessioning handshake protocol between the unit which ignites the cap, and the unit used by the Master Blaster
Master Blaster
Master Blaster may refer to:In music:* "Master Blaster ", a 1980 single by Stevie Wonder* Master Blaster , German dance music band* "Master Blaster", a song from the 1996 album Butterfly Rocket by Nikka Costa...
controlling the shot, ensuring that the emplaced Tovex, detonation cord, and caps can not ignite prematurely.
After detonation the material is completely utilized, there is no discernible residue unless one employs microscopic analysis. Typically Tovex and other commercial explosives employ embedded taggant
Taggant
A taggant can mean a radio frequency microchip used in automated identification and data capture . In such cases, electronic devices use radio waves to track and identify items, such as pharmaceutical products, by assigning individual serial numbers to the containers holding each product...
s which identify the product and often identify the agency which purchased the material.
Features
- capBlasting capA blasting cap is a small sensitive primary explosive device generally used to detonate a larger, more powerful and less sensitive secondary explosive such as TNT, dynamite, or plastic explosive....
sensitive - wide range of bore hole densitiesDensityThe mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
- improved flexibility in loading
- water-resistance
- no nitroglycerin and noxious fumes
- reduced handling, transportation and storage hazards
- high bubble energy (underwater explosionUnderwater explosionAn underwater explosion, also known as an UNDEX, is an explosion beneath the surface of water. The type of explosion may be chemical or nuclear...
) - reduced sound levels and better control on vibrationVibrationVibration refers to mechanical oscillations about an equilibrium point. The oscillations may be periodic such as the motion of a pendulum or random such as the movement of a tire on a gravel road.Vibration is occasionally "desirable"...
s