US3147163A

US3147163A - Sensitized oil-slurried explosives

Info

Publication number: US3147163A
Application number: US51795A
Authority: US
Inventors: George L Griffith; Franklin B Wells
Original assignee: Trojan Powder Co
Current assignee: Trojan Powder Co
Priority date: 1960-08-25
Filing date: 1960-08-25
Publication date: 1964-09-01
Anticipated expiration: 1981-09-01

Description

United States Patent This invention relates to sensitized oil-slurried explosives having a remarkably low oxygen balance, and, more particularly, to sensitized explosives based on an inorganic nitrate and slurried in oil, with water added to reduce the amount of oil needed for slurrying.

Explosive mixtures containing relatively large amounts of water have recently become of considerable interest in the explosive art. They have greater versatility than vdry mixtures, because they can be used under conditions Where water cannot be excluded. The water content is more than that which is absorbed by the components of the mixture, and is sufiicient to act as a suspending agent for the mixture. Such a water content in most cases ranges from about 10% to more than 30%, depending upon the materials present in the mixture and upon the consistency desired.

A slurry having a reasonably stifl? consistency containing as little as 10% Water may be preferred for use in bulk in wet bore holes, where the composition may be diluted with water already present. Thickening or gelatinizing agents are employed when thick slurries are required containing high proportions of water. A slurry which can be poured may be desired for use in bulk in dry bore holes, and such a slurry is easily obtained by using a rather large proportion of water, for example, 20-50%, without a thickening or gelatinizing agent.

Slurries of this type are described in US. Patent No. 2,930,685 to Cook and Farnam, patented March 29, 1960. These compositions are based upon ammonium nitrate as the sole nitrate and are sensitized with TNT, and may contain powdered aluminum. The patentees emphasize a statement made previously by one of them, Melvin A. Cook, in his text The Science of High Explosives, pages 317 to 321, that in such slurries fine grained TNT cannot be used, and that the TNT particles must be coarser than 30 mesh, standard Tyler mesh size.

This is a great disadvantage, since the normal form of TNT is the fine grained form, so that these slurries require a special material. Furthermore, as the patentees themselves point out at column 3, lines 70 to 74, the fine grain particles have a greater sensitivity when dry, and can be detonated in diameters as low as inch with ordinary blasting caps. They also are more easily kept in suspension in the slurry, because they are smaller, whereas Cook et a1. with their larger particles encounter a settling problem which results in the formation of two layers at water contents beyond 18%, With an ammonium nitrate solution on top. However, it is quite clear that in the case of the disclosed TNT slurries, the curve of sensitivity plotted against mesh size moves abruptly towards increased sensitivity at about 30 mesh.

These findings for TNT slurries definitely suggest that finely divided sensitizers should not be used in aqueous slurry form. This of course conforms to the general understanding of the art that water desensitizes powdered explosive mixtures, and Cook et al. indeed point out that the art has always taken extensive precautions both in formulating and in storing explosives to exclude moisture.

In accordance with the instant invention, it has been determined that sensitized explosive slurries of excellent power, brisance, and sensitivity, despite a surprisingly low oxygen balance, can be prepared by slurrying the explosive mixture in oil instead of with water. Small amounts of water can be added, so that the slurry is Patented Sept. 1, 1964 sufficiently sensitive to fire under the desired conditions. However, the amount of Water is always less than will result in separation of oil, or conversion of the slurry into an aqueous slurry, i.e., with water as the suspending medium. Such oil slurries can be formulated with any sensitizer and with any inorganic nitrate or nitrate mixture as the oxidizer to give explosive slurries having high rates of detonation and high power.

The oil slurries of the invention, because of the large amounts of oil, have an unusually low oxygen balance. In fact, their oxygen balances. are lower than any heretofore considered as being in the range for explosives. Only black powders have a lower oxygen balance, but these burn rapidly, and are not regarded as explosives in the usual sense. The effectiveness of these oil slurries is therefore quite unexpected.

Oil slurries have several advantages over water slurries. The oil serves a dual function, not only as a carbonaceous fuel but also as a suspending medium. It is considerably less volatile than water, and therefore, there is less danger of the slurry drying out in storage. In use, such as in bore holes and quarries, a water slurry can create a potentially dangerous situation if a hole were missed Where the explosive had failed to fire. The water slurry would dry out and become flammable and capsensitive. An oil slurry does not have this tendency, and avoids the problem.

Any inorganic nitrate can be employed as the oxidizer. Ammonium nitrate, and nitrates of the alkali and alkaline earth metals, such as sodium nitrate, potassium nitrate, calcium nitrate, magnesium nitrate, strontium nitrate and barium nitrate, are exemplary inorganic nitrates. Sodium nitrate is preferred. Excellent results are obtained with mixtures of ammonium nitrate and another inorganic nitrate, such as sodium nitrate, and mixtures thereof with ammonium nitrate are preferred.

In such mixtures, the relative proportions of ammonium nitrate and other inorganic nitrate or nitrates in the mixture are important to the explosive efiiect. The ammonium nitrate should be in a proportion within the range from about 0 to about and the other nitrate or nitrates in a proportion within the range from about 100 to about 25%. For optimum power, the proportions are from 10 to 70% ammonium nitrate and from 90 to 30% of the other nitrate or nitrates. A mixture of approximately 15 to 25% ammonium nitrate and 75 to other nitrate, is in most cases the best. The particular proportions of oxidizers selected within these ranges will depend upon the sensitivity and explosive effect desired, and these in turn are dependent upon the particular nitrate or nitrates used.

The inorganic nitrates may be fine, coarse or a blend of fine and coarse materials. Mill and prill inorganic nitrates are quite satisfactory. For best results, sodium nitrate should pass a 20 mesh (US. Standard) sieve, and at least 50% of the ammonium nitrate should be 'finegrained. In mixtures of these nitrates, the more sodium nitrate that is present, the higher the proportion of fine grain ammonium nitrate that is desirable for optimum explosive power.

The high power of these compositions is shown by the crater values, which give a true picture of the power from the standpoint of the practical application. It has been found that the ballistic pendulum test, normally relied upon to estimate power, is misleading in the case of the sensitized explosive slurries of the invention, and in many cases suggests a low power which is not confirmed by the crater test. Details of the crater test are given below in conjunction with the examples.

The explosive slurries of the invention contain enough oil to act as a suspending medium for the solid ingredients. Some explosives and sensitizers are capable of absorbing surprisingly large amounts of oil. The oil added in the slurries of the invention is always enough more than this amount to suspend the mixture. Usually, 7% oil is enough to barely slurry the mixture, but more may be required to make the slurry flowable. The practical upper limit is set by excessive dilution and dissipation of the explosive power, taking into account any loss of oil by volatilization and absorption into the ground. In most cases, the preferred range of oil content will be from about 10% to 40%, although in some cases as much as 50% can be used. In these proportions, the viscosity of the oil is of course a factor to be taken into account. Any oil can be used as the suspending medium. Petroleum-derived hydrocarbon oils are readily available, and are preferred because of their low cost. The viscosity can range from very thin, such as 50 SSU at 100 F., to quite heavy oils, up to about 1200 SSU at 100 F. Kerosene, fuel oil, 100 SSU parafiin oil, light straw paraffin oil, SAE 10 to 50 lubricating oils, and hydraulic oils are exemplary.

If oil is the only liquid present, the slurry may be seriously deficient in oxygen, reducing sensitivity and also brisance and power. Water is added in a small amount, less than will displace the oil as the suspending medium or will result in separation of oil, to mitigate this deficiency and restore sensitivity, brisance and power to an acceptable level. Surprisingly large amounts of water can be added without separation of oil occurring.

Water is thinner than most of the oils that would be used, and will consequently reduce the consistency of the slurry. Less water than oil of the same viscosity is required to slurry the mixture, so that a mixture of oil and water may be more advantageous than oil alone for this reason. In all cases, oxygen balance must also be taken into account in determining the proportions of water and oil that should be used for a given explosive slurry. Good proportions for most sensitized slurries, using finely divided nitrate oxidizer and sensitizer, taking all of the above factors into consideration, are from 2 to 10% water, with from 10 to 30% oil. Such slurries have a satisfactory fluidity, which can be reduced by addition of an appropriate amount of thickening agent, as will be described later.

The sensitizer can be any of those chemicals known as sensitizers in this art including, for example, dinitrotoluene, trinitrotoluene, pentaerythritol tetranitrate, nitrostarch, pentolite (an equal parts by weight mixture of pentaerythritol tetranitrate and trinitrotoluene), cyclonite (RDX, cyclotrimethylene trinitroamine), nitrocellulose, composition B (a mixture of up to 60% RDX, up to 40% TNT and 1 to 4% wax), cyclotol (composition B without the wax), tetryl, smokeless powder, and carbine ball powder. Nitrostarch is preferred because it also aids in imparting a proper consistency to the slurry.

The relative proportions of nitrate oxidizer and sensitizer will depend upon the sensitivity and explosive effect desired, and again, these in turn are dependent upon the particular nitrate and sensitizer. The proportions are not critical in any way. For optimum effect, the nitrate is used in an amount within the range from about 50 to about 75%, and the sensitizer in an amount within the range from about 15 to about 25%. The preferred ratios of nitratezsensitizer are from 5:1 to 2:1. From about 35 to about 75% nitrate oxidizer and from about to about 30% sensitizer give quite satisfactory results in the slurried explosive mixtures of the invention. About 80% mixed nitrates and 20% sensitizer give the best results. When the amount of sensitizer is in the lower part of the range, a larger booster is needed, so that in a 2 /2 to 3 inch hole a slurry containing only 10% nitrostarch requires a 60 g. pentolite booster. At amounts beyond 20%, the sensitizing elr'ect falls off, and is no longer proportional to the amount of sensitizer added. Thus, a slurry containing 30% nitrostarch requires a 2 g. pentolite booster, whereas one containing 20% nitrostarch requires a 3 g. pentolite booster. Thus, amounts beyond 20% may not be economically advantageous.

Sensitizers of any particle size can be used, as has been indicated, and can be fine, coarse or a blend of fine and coarse material. Some materials such as nitrostarch are commercially available as very finely-divided powders, and so also is trinitrotoluene. Such available materials are employed to advantage, in preference to specially prepared materials such as coarse TNT, because they are less expensive. The finely-divided materials, less than 30 mesh (U.S. Standard), are preferable to the coarse materials because they are more easily slurried to form a stable composition, and because in most cases they tend to produce compositions having a greater sensitivity and a higher crater value.

In addition to these materials, which are the essential ingredients, the explosive slurries may include a particulate metal fuel, for example, aluminum powder, flake aluminum, and ferrosilicon. A metal fuel when present will usually comprise about 1 to about 25% of the mixture. The oil serves as the carbonaceous fuel, so that no other fuel of this type is required. However, under some circumstances additional carbonaceous materials can be added, such as powdered coal, petroleum oil, coke dust, charcoal, bagasse, dextrin, starch, wood meal, flour, bran, pecan meal or similar nut shell meals, and paraffin oil. The carbonaceous fuels will usually comprise from 5 to about 40% of the mixture, including the oil. Mixtures of such metal and carbonaceous fuels can also be used.

An antacid, such as zinc oxide, may be added if desired.

The consistency of the slurry for any given amount of water can be increased to meet any need by incorporating a thickening or gelatinizing agent for thickening the oil and also, if enough water is present to markedly affect consistency, the water. In this way, it is possible to prepare a thick slurry containing a large proportion of oil and water for use in bulk in dry bore holes.

The oil thickening agent is oil-soluble or oil-dispersible, and inert to the other ingredients present.

Noncarbonaceous inorganic oil thickeners useful in making thickened oils and greases such as finely divided silica, available under the trade names Cab-O-Sil and Ludox, and silica aerogels,-for example, Santocel ARD and Santocel C, and like inorganic gelling agents, such as alumina, attapulgite and bentonite, can be used. Other gelling agents are disclosed in U.S. Patents Nos. 2,655,476 and 2,711,393. These are well known materials, and any of these known to the art can be used. The amount of such thickening agent will depend on the consistency desired, and usually will be within the range from 0 up to about 5%. Enough thickener can be added to gel the oil, and water-proofing agents such as are disclosed in U.S. Patents Nos. 2,554,222, 2,655,476 and 2,711,393 can be incorporated as well to impart water resistance to the gelled slurry.

When relatively large proportions of water are present, Water-soluble or water-dispersible thickeners can be added, for example such as carboxymethyl cellulose, methyl cellulose, guar gum, psyllium seed mucilage, and pregelatinized starches such as Hydroseal 3B. The amount of such thickening agent will depend on the consistency desired, and usually will be within the range from 0 to about 5%.

The explosive mixture is readily prepared by simple mixing of the ingredients. The solid materials, including the inorganic nitrate and sensitizer, and additional fuel and antacid, if any, would usually be mixed first to form a homogeneous blend, and then sufficient oil, and water, and oil and water thickener, if required, would be added to bring the mixture to the desired consistency, which can range from a gelled oil or thick, barely pourable mixture to a quick-flowing liquid.

The explosive slurry will ordinarily be fired with the aid of a booster charge and under high confinement, and combinations of the explosive slurry and a booster in the same container or separately packaged as a composite in one container can be prepared and marketed as a combined blasting agent. Any conventional booster charge available in the art can be employed, of which pentaerythritol tetranitrate and pentolite are exemplary. Blasting caps can be used as the booster when the slurry is sufficiently sensitive.

The following examples in the opinion of the inventors represent the best embodiments of their invention.

The power of the explosive slurries of the examples was determined by-a cratering test which was carried out as follows. The slurry was loaded into a polyethylenelined cartridge 4 /2 inches in diameter and 15 inches long. This cartridge was placed upright in a hole in the ground 30 inches deep, and was tamped firmly in place with loose dirt until the level of tamping reached that of the surrounding ground. A 1 pound cast pentolite (mixture of equal parts pentaerythritol tetranitrate and trinitrotoluene) booster at the top of the cartridge was used for initiation. The volume of earth moved in cubic feet is then determined, with a correction made for the booster, and the number of cubic feet of earth moved per pound of explosive is taken as the crater value. This value shows the power of the explosive slurry from the standpoint of practical application.

In addition to crater value, the standard tests for determining ballistic pendulum value, sensitivity in a 2 inch pipe, and rate of detonation in a 2 inch pipe, were also employed. In the sensitivity tests, when the scope of the standard caps had been passed there were used progressively, as more powerful initiators, 3 g. PETN booster, and then 5, 10, 15, 20, 25, 30, 40, 50, 60, 75, 100, 125, 150, 200 and 250 g., and then M2 pound, 1 pound, and 2 pound, cast pentolite boosters.

Example 1 An oil slurry was prepared using dry mill nitrostarch, ammonium nitrate, sodium nitrate, and water. The ammonium nitrate comprised 50% prills and 50% 30 mesh grained ammonium nitrate. The sodium nitrate was 20 mesh. The three solid materials were mixed thoroughly. There was then added Zinc oxide, Cab-O-Sil and flake aluminum, and then the oil and water were added. The proportions of the .final explosive slurry were as follows:

The density, ballistic pendulumwalue, sensitivity in a 2 inch pipe, and crater value were determined, with the following results:

Density 1.46. Ballistic pendulum value 9.4. Sensitivity in 1% inch pipe 1 g. PETN. Crater value (cubic feet per pound) 6.5.

1 Cast pentolite booster. 2 Pentaerythritol tetranitrate.

Rates of detonation were run in two inch pipe. The rate was 5149 m./ sec.

Example 2 An oil slurry was prepared according to the procedure set forth in Example 1, based upon the same amount of ammonium nitrate and sodium nitrate, but containing 20 *Pentaerythritol tetranitrate.

6 parts of 14 mesh TNT in place of the nitrostarch. The final slurry had the following composition:

Percent by weight 14 mesh trinitrotoluene 20.0 Ammonium nitrate 44.6 Sodium nitrate 11.0 Zinc oxide 0.3 Cab-O-Sil silica 0.1 Flake aluminum I. 3.0 Water. 5.0 SSU paraflin oil 16.0

The comparative tests set forth above showed a good ballistic pendulum value, and good sensitivity in 1% inch pipe. This slurry was not nearly as powerful as the slurry based on nitrostarch, but it nonetheless had adequate power for many uses.

Example 3 An oil slurry was prepared by the method of Example -1, based upon the same ammonium nitrate and sodium nitrate but in different proportions, and having the following composition:

Percent by weight Dry nitrostarch 20.0 Ammonium nitrate 35.6 Sodium nitrate 20.0 Zinc oxide 0.3 Cab-O-Sil silica 0.1 Flake aluminum 3.0 Water 5.0 100 SSU paraflin oil 16.0

The comparative tests gave the following results on this slurry:

Density 1.495. Ballistic pendulum value 9.0. Sensitivity in 1% inch pipe 1 10 g. PETN.

1 Cast pentolite booster.

Rates of detonation were run in 2 inch pipe. The rate :of detonation was 5191 m./ sec. In the cratering test this slurry moved 8.3 cubic feet of earth per pound of ex- :plosive.

Example 4 An oil slurry was prepared by the method of Example -1 based upon the same ammonium nitrate and sodium nitrate but in different proportions, and having the following composition:

Percent by weight slurry:

Density 1.52. Ballistic pendulum value 8.5; Sensitivity in 1% inch pipe 1 10 g. PETN.

1 Cast pentolite booster.

Rates of detonation were run in 2 inch pipe. The rate of detonation was 5258 m./ sec. In the cratering test this slurry moved 9.4 cubic feet of earth per pound of explosive.

Example An oil slurry was prepared by the method of Example 1 based upon the same ammonium nitrate and sodium nitrate but in different proportions, and having the following composition:

The comparative tests gave the following results on this slurry:

Density 1.595. Ballistic pendulum value 8.0. Sensitivity in 1% inch pipe 1 5 g. pentolite.

1 Cast pentolite booster.

Rates of detonation were run in 2 inch pipe. The rate of detonation was 5258 m./sec. In the cratering test, this slurry moved 10.0 cubic feet of earth per pound of explosive.

When the formulation is modified so that only 3 parts of Water are used, then 22 parts of oil are required, and when no water is present 34 parts of oil are necessary to give a slurry-like consistency. With so much oil present the composition is very seriously deficient in oxygen, and .this reduces the sensitivity to the point where the mixture fails to fire with a 1 lb. cast pentolite booster in a 3 inch iron pipe. The brisance and power also suffer materially.

When the formulation is prepared with 7 parts of water, the addition of 3 parts of oil liquefies it to about the maximum extent desired. Further addition of oil makes the composition too liquid to be of great interest. Also, when more than 3 parts of oil are present, the oil begins to separate. When 6 parts of water and 3 parts of oil are used there is no separation, but the consistency is very stiff. With 6 parts of Water and 8 parts of oil the consistency is satisfactory for most purposes and there is no separation. All of these are oil slurries, and illustrate the wide range of water and oil contents that can be used in these slurries.

Example 6 An oil slurry was prepared by the method of Example 1 based upon the same ammonium nitrate and sodium nitrate, but in different proportions, and having the following composition:

Percent by weight The comparative tests gave the following results on this slurry:

Density 1.62. Ballistic pendulum value 7.4. Sensitivity in 1% inch pipe 50 g. pentolite.

1 Cast pentolite booster.

Rates of detonation were run in 2 inch pipe. The rate of detonation was 5107 m./ sec. In the cratering test described in Example 1, this slurry moved 9.3 cubic feet of earth per pound of explosive.

8 Example 7 An oil slurry was prepared by the method of Example 1, based upon sodium nitrate of the same type as in Example 1.

Percent by weight Mill nitrostarch 20.0 Sodium nitrate 55.6 Zinc oxide 0.3 Cab-O-Sil silica 0.1 Flake aluminum 3.0 Water 5.0 100 SSU paraffin oil 16.0

The comparative tests gave the following results on this slurry:

Density 1.64.

Ballistic pendulum value 6.9.

Sensitivity in 2 /2 inch pipe 1 lb. pentolite failed.

Crater value (cubic feet of earth per pound) 8.2.

1 Cast pentolite booster.

A comparison of Examples 1 and 3 to 7 shows that the crater value reaches an optimum within the preferred proportions of from 75 to of sodium, and is at a maximum at approximately a 45 %11% mixture of sodium and ammonium nitrates. On the other hand, the ballistic pendulum values decrease steadily as the amount of ammonium nitrate is decreased and the amount of sodium nitrate is increased. This shows the misleading character of the ballistic pendulum test, as applied to these explosive slurries.

Example 8 An oil slurry was prepared of the same type as that of Example 5, employing fine grained TNT and having the following composition:

1 U.S. Standard Screens.

The comparative tests showed this slurry to have a relatively low ballistic pendulum value, good sensitivity in 1% inch pipe, and a good crater value.

Example 9 An oil slurry Was prepared having the same composition as Example 5, substituting a coarse grained trinitrotoluene, of which passed a 20 mesh screen but was 9 held on a 14 mesh screen. This slurry had the following composition:

The comparative tests showed this slurry had a poor ballistic pendulum value, poor sensitivity in 1% inch pipe, and a fair crater Value.

Example 1 An oil slurry was prepared having the same composition as Example 5, with 50 mesh pentaerythritol tetranitrate as the sensitizer, and having the following composition:

Percent by weight Pentaerythritol tetranitrate 20.0 Mill ammonium nitrate 11.0 Mill sodium nitrate a 44.6 Zinc oxide 0.3 Cab-O-Sil silica 0.1 Flake aluminum n. .t n 3.0 Water fi 5.0 100 SSU parafiin oil 16.0

The comparative tests showed this slurry to have relatively low ballistic pendulum value, good sensitivity in 1% inch pipe and a good crater value.

Example" 11 An oil slurry was prepared having the same composition as Example based upon ball powder (30 mesh) as the sensitizer, and having the following composition:

Percent by weight Ball powder 20.0 Ammonium nitrate 11.0 Sodium nitrate 44.6 Zinc oxide 0.3 Cab-O-Sil silica 0.1 Flake aluminum 3.0 Water 5.0 100 SSU paraflin oil 16.0

The comparative tests showed this slurry to have a poor ballistic pendulum value, good sensitivity in 1% inch pipe, and a good crater value.

Example 12 An oil slurry was prepared having the same composition as Example 5, based upon 40 mesh cyclonite as the sensitizer, and having the following composition:

Percent by weight Cyclonite 20.0

The comparative tests showed this slurry had a poor ballistic pendulum value, good sensitivity in 1% inch pipe, and a good crater value.

Example 13 An oil slurry was prepared as in Example 1, and similar in formulation to Example 5, but based upon a mixture of mill ammonium nitrate and anhydrous strontium nitrate. This slurry had the following composition:

Percent by weight Dry nitrostarch 20.0 Ammonium nitrate 11.0 Anhydrous strontium nitrate 44.6 Zinc oxide 0.3 Cab-O-Sil silica 0.1 Flake aluminum 3.0 Water 5.0 SSU paralfin oil 16.0

The comparative tests gave the following results on this slurry:

Density 1.60. Ballistic pendulum value 8.0. Sensitivity in 1% inch pipe 5 g. PETN. Rate in pipe at the density noted above in m./sec. 5258 (Z'inch). Crater value (cubic feet of earth per pound) 10.0.

Example 14 A slurry was prepared as in Example 1 and similar in formulation to Example 5, but based upon a mixture of mill ammonium nitrate and anhydrous barium nitrate. This slurry had the following composition:

Percent by weight Dry nitrostarch The comparative tests showed this slurry to have a poor ballistic pendulum value, excellent sensitivity in 1% inch pipe, and an excellent crater value.

All proportions in the specification and claims are by weight of the entire explosive oil slurry.

We claim:

1. An explosive oil slurry consisting essentially of from about 35 to about 75% by weight of an inorganic nitrate oxidizer; from about 10 to about 35% by weight of a sensitizer selected from the group consisting of dinitrotoluene, trinitrotoluene, pentaerythritol tetranitrate, nitrostarch, pentolite, cyclonite, nitrocellulose, composition B, cyclotol, tetryl, smokeless powder, and ball powder; and sufficient oil within the range from about 7% to about 50% by weight to act as a suspend ing medium for the solid ingredients.

2. An explosive oil slurry in accordance with claim 1 in which the inorganic nitrate is sodium nitrate.

3. An explosive oil slurry in accordance with claim 1 in which the inorganic nitrate oxidizer is a mixture of ammonium nitrate and an inorganic nitrate selected from the group consisting of alkali and alkaline earth metal nitrates.

4. An explosive oil slurry in accordance with claim 1 comprising water in an amount within the range of from about 2 to about 10% by weight to lessen the consistency of the slurry.

5. An explosive oil slurry in accordance with claim 1 11 including from about 1 to about 25% of a metal fuel.

6. An explosive oil slurry in accordance with claim 5 in which the fuel is particulate aluminum.

7. An explosive oil slurry in accordance with claim 1 also including a thickening agent.

8. An explosive oil slurry in accordance with claim 7 in which the thickening agent is an inorganic oil-gelling agent.

9. A blasting agent comprising an explosive oil slurry in accordance with claim 1 in combination with a booster charge.

10. A blasting agent in accordance with claim 9 in which the booster is pentaerythritol tetranitrate.

11. A blasting agent in accordance with claim 9 in which the booster is pentolite.

12. An explosive oil slurry consisting essentially of from about 50 to about 75% of an inorganic nitrate oxidizer; from about 15 to about 25% of a sensitizer selected from the group consisting of dinitrotoluene, trinitrotoluene, pentaerythritol tetranitrate, nitrostarch, pentolite, cyclonite, nitrocellulose, composition B, cyclotol, tetryl, smokeless powder, and ball powder; from 1 to about 25 of a metal fuel; sufficient oil in an amount within the range from 7 to about 50% to act as a suspending medium for the solid ingredients; water in an amount within the range from about to about 10%; and a thickening agent in an amount within the range from about 0 to about 13. An explosive oil slurry in accordance with claim 12 in which the fuel is particulate aluminum.

14. An explosive oil slurry in accordance with claim 1 in which the sensitizer is nitrostarch.

15. An explosive oil slurry in accordance with claim 1 in which the sensitizer is trinitroluene.

16. An explosive oil slurry in accordance with claim 1 in which the sensitizer is cyclonite.

17. An explosive oil slurry in accordance with claim 1 in which the sensitizer is pentaerythritol tetranitrate.

18. An explosive oil slurry in accordance with claim 1 in which the sensitizer is ball powder.

19. An explosive oil slurry consisting essentially of from about to about by weight of an inorganic nitrate oxidizer comprising a mixture from about 15 to about 25% ammonium nitrate and from about 75 to about other inorganic nitrate; from about 10% to about 30% by weight of a sensitizer selected from the group consisting of dinitrotoluene, trinitrotoluene, pentaerythritol tetranitrate, nitrostarch, pentolite, cyclonite, nitrocellulose, composition B, cyclotol, tetryl, smokeless powder, and ball powder; and suflicient oil within the range from about 7% to about 50% by weight to act as a suspending medium for the solid ingredients.

References Cited in the file of this patent UNITED STATES PATENTS 2,768,073 Davidson Oct. 23, 1956 2,860,041 Griffith Nov. 11, 1958 2,867,172 Hradel Jan. 6, 1959 2,930,685 Cook et a1. Mar. 29, 1960 2,997,378 Cox et a1. Aug. 22, 1961 3,048,103 Blair et a1 Aug/ 7, 1962 3,053,707 Davis et a1. Sept. 11, 1962

Claims

1. AN EXPLOSIVE OIL SLURRY CONSISTING ESSENTIALLY OF FROM ABOUT 35 TO ABOUT 75% BY WEIGHT OF AN INORGANIC NITRATE OXIDIZER; FROM ABOUT 10 TO ABOUT 35% BY WEIGHT OF A SENSITIZER SELECTED FROM THE GROUP CONSISTING OF DINITROTOLUENE, TRINTROTOLUENE, PENTAERYTHRITOL TETRANITRATE, NITROSTARCH, PENTOLITE, CYCLONTIE, NITROCELULOSE, COMPOSITION B, CYCLOTOL, TETRYL, SMOKELESS POWDER, AND BALL POWDER; AND SUFFICIENT OIL WITHIN THE RANGE FROM ABOUT 7% TO ABOUT 50% BY WEIGHT TO ACT AS A SUSPENDING MEDIUM FOR THE SOLID INGREDIENTS.