US1671793A - Blasting explosive - Google Patents

Description

, ticalstandpoint and by law, to those mines Patented May 2 9, 1928.

BUREN I. STOOPS, OF KEN VIL, NEW JERSEY, ASSIGNOR TO HERCULES POWDER COH- PANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

BLASTING EXPLOSIVE.

No Drawing.

My invention relates to an improvement in blasting explosives and more partlcularly to blasting explosives of the permissible type such as are .used for example in mines containing gas or dust,

In the provision of a blasting explosive and especially a blasting explosive for use in coal mines, it is desirable that the nature of the explosive be such that it will act to displace the coal without shattering it, in order that the production of fine or small sizedcoal may be reduced to a minimum and the production of the more valuable large sized coal maintained at a maximum. It has been recognized that in order to avoid shattering of the coal it is essential that an explosive be used of such a character that it will occupy a relatively large volume compared to its strength. so that the pressure of explosion shall be distributed over a relativey large area and have a rendln effect, rather than be concentrated in a re atively small area with consequent shattering efiect.

Heretofore the most desirable explosive known for use in blasting out coal has been black powder, which being a relatively weak explosive and non-detonating will occupy a volume relatively large compared to its pressure of explosion, with the result that it has to a high degree the desirable rendlng action, with the production of alarge proportion of lump coal, as compared with the undesirable shattering action and the production of large proportions of fine coal and dust;

Black powder, though it provides a blasting explosive-of desirable characteristics for coal mining,- is open to a serious objection in that on burning it develops a high heat and gives ofl a flame of such temperature as to effectively ignite explosive gas or dust which mayexist at its point of use in a mine. As a result'of the high temperature flame developed with the use of black powder itsuse in mines containing gas or which are dusty is prohibitively dangerous, and its use in coal mines is'restricted, both from the prac- Which are free from gas and in which pres cautions are taken to lay the dust.

Black powder is objectionable for various other reasons, chief among which is the fact that it is readily ignitable by a spark and Application filed November 4, 1927. Serial No. 231,157.

storage in the vicinity of electric-wires and devices, or of machinery, such as steam shovels and locomotives, which are likely to throw out sparks.

Numerous efforts have been made to modify black powder to adapt it for use in mines generally and to render it safe in handling and storage, without any substantial success, however. In attempting the modification of black powder various ingredients have been added to it with a view of reducing the flame temperature, and its rotection from accidental ignition has een sought by compressing it into cylindrical pellets, putting up the pellets in paper cartridges and packing the cartridges in Wooden cases instead of in the usual met-a1 kegs in which loose black blasting powder is customarily packed. The various attempts to reduce the flame temperature" of black powder have not resulted in any such eflective reduction as to enable any expansion in the use of such powder in mines, and the advantage of reduction in the risk of accidental ignition obtained from the improved form of packing the powder is negatived by increased cost and the fact that the solid sticks or cartridges of powder will not flow into the irregularities of a bore hole as does the loose powder. 1

As a substitute for black powder for use in mines containing gas and dust the socalled permissible explosive was devised. The permissible explosive, which ordinarily consists of a mixture of an explosive salt, as ammonium nitrate, an oxidizing salt, as sodium nitrate, a carbonaceous material, as wood meal, and a sensitizer, as nitroglycerine, develops a flame temperature substantially lower than that of black powder and has proved substantially safe for use in mines containing gas and dust. However, the permissible explosive is 0 en to the serious'objection that it is high y concentrated with relation to its power, as compared with black powder, with the result that it operates to shatter the coal.

Numerous eflorts have been made to modify the permissible explosive with a view to'reducing its density in proportion to its power in order to avoid the shattering effect of its use, but such efiorts have been substantially unsuccessful from the standpoint of the production of a permissible explosive having the non-shattering efl'ect of lack powder. In the modification of permissibles for the reduction of density various low density carbonaceous materials have been used and the density of permissibles has been lowered to an extent which enables the production of from about 36037 5. standard 1% x 8 inch cartridges per hundred pounds, as compared with 270 standard cartridges per hundred pounds. Even permissible explosives having a cartridge count of, say, 375 er hundred pounds are, however, not sufliclently low in density to be satisfactory from the standpointof prevention of shattering and heretofore further decrease in the density of such explosives has been prevented due to the fact thatthe proportion of carbonaceous material relative to the explosive and oxidizing salts is limited for the production of an effective explosive, and to the fact that the low density carbonaceous materials are highly absorptive and when used in large proportions absorb the sensitizer, usually nitroglycerine, with the result that the explosive becomes insensitive and eithpf fails in propagation or cannot be fired at a In the efiorts heretofore made in the attempt to dispose permissible explosives over an increased area relative to their strength, in the loading of a bore hole air spaces have been left between individual cartridges, or between the to cartridge and the tamping, so that the vio ence of the shock of the explosive is damped by the compression of the air on such spaces or space, to the end that the maximum pressure of the explosion would be reduced, and the efi'ective pressure distributed over a greater area of coal. Such method of loading is difficult of application 7 since spacers must be provided and placed between the individual cartridges, or between the cartridges and tamping, and it frequently occurs where the individual cartridges are spaced. apart that the various sticks may fail to detonate from one to another across the intervening space, with the result that unexploded cartridges are left in the broken coal.

If the spacing of the several cartridges in the borehole could be avoided, still retaining the same volume of explosive plus space, the desirable efiect of the cushion of air would be attained. This, it will be seen in the following, is accomplished in my invention, or in other words, the air space is placed within the cartridge rather than without the cartridge as has hitherto been the case.

Thus it is well known to those skilled in the art, including the users as well as the producers of blasting explosives, that heretofore there has not been produced a. blasting explosive having the desirable and eswhich will possess all of the essential characteristics of permissibles, as heretofore produced, and which at the same time will have a density with relation. to its power such that on explosion it will be substantially the same in action as black powder.

Further objects of my invention are to provide an explosive of the permissible type of such a density that it will enable a cartridge count in excess of four hundred and twentyfive standard 1 x8 inch cartridges per hundred pounds and at the same time such an explosive which will retain its sensitivity to a high degree, even under adverse conditions such as in storage at relatively high temperature.

The blasting explosive in accordance with my invention comprises essentially an explosive salt, as ammonium nitrate, an oxidizing salt, as sodium nitrate, a sensitizer, as nitroglycerine, nitropolyglycerine, or the like, and a carbonaceous material of maximum low density, as for example balsa wood (Ochroma Zagopus), bongo wood (Oaoam'lesz'a platwmpolz'a), or the like.

For example, in making up the explosive in accordance with my invention the carbonaceous material, as balsa wood, bongo wood, or the like, is reduced to a finely divided condition, for example to the form of saw dust, and the explosive salt ingredient of the'explosive impregnated into the carbonaceous material, so that an appreciable proportion of the explosive salt ingredient is supported in intracellular relation with respect to the carbonaceous material. The im regnation of the explosive salt into the car onaceous material is preferably accomplished by the method described in detail in an application for United States patent filed by Buren I. Stoops, Serial Number 180,622. filed April 2, 1927, which includes admixing the explosive salt with a salt containing water of crystallization, as for example magnesium nitrate, calcium nitrate, ferric nitrate, aluminum nitrate, and/or the like, and heating the mixture sufficiently to release the water of crystallization in which the salts will be dissolved. The carbonaceous material when subjected to the melt will absorb and become impregnated with the salt solution and on cooling the water of crystallization will return to the salt in WlllClill] was originally present and thesalts will recrystallize, in appreciable proportion in intraerably with an explosive salt and a salt con-. taining water of crystallization, is then admixed mechanically with a finely ground .oxidizing salt, as sodium nitrate, potassium nitrate, or the like, and with a sensitizer as nitroglycerine, nitropolyglycerine, or the e. As an example of an explosive embodying my invention and having a cartridge count' of in excess of four hundred and twentyfive 1 /;x8 inch cartridges per hundred pounds, the following formula showing ran es of proportions of the several ingre ients will be illustrative:

As a more specific example of an explosive embodying my invention and having a cartridge count in excess of four hundred and twenty-five 1 4x 8 inch cartridges per hundred pounds, the following will be illustrative:

F orm/ula B.

Per cent by weight.

Nitroglycerine, nitropolyglycerine,

etc 10.0 Ammonium nitrate 47. 0 Magnesium nitrate 15.0 Sodium nitrate 12.0 Balsa sawdust 16.0

Charactefistios.

Sensitiveness to detonation, fresh 10" Sensitiveness to detonation after 24.-

hours 100 F 10" Sensitiveness to detonation through crimps 4 Velocity of detonation, m/s 2200 Cartridge countl -8 inch- 500 per 100 lbs.

by weight of carbonaceous material of maximum low density, the high absorptive capacity of which is greatly reduced by the impregnation with the explosive salt and the salt containing water of crystallization.

The large proportion of maximum low density material greatly reduces the density of the explosive as a whole and the impregnation of the low density material reduces the absorption of the nitroglycerine, or other sensitizer, thereby avoiding loss of sensitivity by the explosive.

The explosive in accordance with my invention is of a density such that the volume occupied thereby, for example in a bore hole,

with relation to its strength is substantially the same in proportion as that of black blasting powder and the explosive, usable with safety in dusty and gaseous mines, will when loaded, in the ordinary manner, act in substantially the same manner as black powder, in that it will displace orblow down coal without shattering. The density of the explosive is such that from in excess of four hundred and twenty-five to in excess of five hundred standard 1% x 8 inch cartridges may beproduced per hundred pounds, and

at the same time the explosive is of adequate v power and will retain its sensitivity to a marked degree. In connection with the above descriptio of the explosive according to my invention and with reference to the formulae given by way of example, it will be understood that the essence of my invention lies in the use of a carbonaceous -material of maximum low density, such as balsa wood, or bongo wood, and. which have a high absorptive capacity, the carbonaceous ingredient being impregnated, preferably with an appreciable quantity of the explosive'salt ingredient of the explosive and desirably with an explosive salt admixed with a salt containing water of crystallization, which simplifies the operation of impregnation and results in the production of a more satisfactory impregnated material, the salt containing water of crystallization not only acting to simplify the operation of impregnation but acting in the finished explosive as a flame dampener. It will be understood that-the carbonaceous material may be impregnated with a salt other than an explosive salt and, for example, the carbonaceous material may be impregnated with an oxidizing salt. with a salt containing water. of crystallization, or with mixtures of salts.

It will be understood that the'explosive in accordance wit-h my invention is not dependent upon the use of any particular explosive salt, oxidizing Salt, salt COIltaining water. of

crystallization, or sensitizer, since. operable equivalents for the ingredients specified herein-may be used without departingfrom.

my invention; and it will be further under- 5 ing from my invention, and shall be included within the scope of the-claims appended hereto.

It will be further understood that in the explosive embodying my invention the ex- )plosive salt and/or salt containing water of crystallization need not in total quantity be impregnated within the carbonaceous material, since it is only necessary that the carbonaceous material be impregnated sufa .ficiently to reduce its absorptive capacity to 'a' point at which it will not absorb the sensitizer to an extent that the explosive will become insensitive. Thus it will be understood thatin the explosive according to my invention part of theexplosive salt and/or salt containing waterof crystallization may be free, or in mechanical admixture with the carbonaceous material, and part impregnated therein, the proportion impregnated in the carbonaceous material depending upon W ters Patent is 1. A blasting explosive including as ingredients a sensitizer and a carbonaceous material having a salt in intracellular relation. the carbonaceous material being of low density, normally highly absorptive, and of such a character and in such quantity ,as to enable a cartridge count of in excess of four hundred and twenty-five 1 4 x 8 inch cartridges per hundred pounds of the explosive.

2. A blasting explosive including as ingredients a sensitizer and a carbonaceous material containing an explosive salt, in intracellular relation, the carbonaceous materiall being of low density, normally highy absorptive, and of such a character and in such quantity as to enable a cartridge count in excess of four hundred and twenty-five 1% x 8 inch cartridges per one hundred pounds of the explosive.

3.'A blasting explosive including as ingredients a sensitizer and a carbonaceous material containing a nitrated salt in intracellular relation, the carbonaceous material being of low density, normally highly absorptive, and of such a character and in such amount as to enable a cartridge count in excess' of four hundred and twenty-five 1 /4 x 8 inch cartridges per one hundred pounds of the explosive.

4. A blasting ,explosive including as ingredients a sensitizer and a carbonaceous material containing ammonium nitrate in intracellular relation, the carbonaceous material being of low density, normally. highly absorptive, and of such a character and in such quantity as to enable a cartridge count in excess of four hundred and twenty-five 1 x 8 inch cartridges per one hundred pounds of the explosive.

5. A blasting explosive including as ingredients a sensitizer and a carbonaceous material containing metallic salt in-intracellular relation, the carbonaceous material being of low density, normally highly absorptive and of such a character and in such quantity as to enable a cartridge count in excess of four hundred and twenty-five 1% x 8 inch cartridges, per one hundred pounds of the explosive.

6. A blasting explosive including as ingredients a sensitizer and a carbonaceous material containing a salt containing water of crystallization in intracellular relation, the carbonaceous material being of low density, normally highly absorptive, and of such a character and in such amount as to enable a cartridge count in excess of four hundred and twenty-five 1% x 8 inch cartridges per one hundred pounds of the explosive.

7. A blasting explosive containing as ingredients a sensitizer and a carbonaceous material containing a plurality of salts, one of which is a salt containing water of crystallization, in intracellular relation, the carbonaceous material being of low density, normally highly absorptive, and of such character and in such quantity as to enable a cartridge count of in excess of four hundred and twenty-five cartridges per one hundred pounds of the explosive.

8. A blasting explosive including as ingredients a sensitizer and a carbonaceous material containing an explosive salt and a. salt containing water of crystallization in intracellular relation, the carbonaceous material being of low density, normally highly absorptive, and of such a character and in such quantity as to enable a cartridge count of in excess of four hundred and twenty-five 1% x 8 inch cartridges per one-hundred pounds of the explosive.

9. A blasting explosive? including as ingredients a sensitizer and a carbonaceous material containing a nitrated salt and a stiltcontaining water of crystallization in intracellular relation, the carbonaceous material being of low density, normally highly absorptive, and of such character and in such quantity as to enable a cartridge count of in excess of four hundred and twentyfive 1 x8 inch cartridges per one hundred poun s of the explosive. t

10. A blasting explosive including as 1ngredients a sensitizer and a carbonaceous material containing ammonium nitrate and a salt containing water of crystallization in intracellular relation, the carbonaceous material being of low density, normally highly absorptive, and of such a character and in such quantity as to enable a cartridge count in excess of four hundred and twenty-five 1 4 x 8 inch cartridges per one hundredpounds of the explosive.

11. A blasting explosive including as ingredients a sensitizer and a carbonaceous material containing metallic salt and a salt containing water of crystallization in intracellular relation, the carbonaceous material being of low density. normally highly absorptive, and of such a character and in such quantity as to enable a cartridge count of in excess of four hundred and twenty-five 1 x 8 inch cartridges per one hundred pounds of the explosive.

12. A blasting explosive including as ingredients a sensitizer and a carbonaceous material containing a nitrated salt and magnesium nitrate in intracellular relation, the carbonaceous material being of low density, normally highly absorptive, and of such a character and in such quantity as to enable a cartridge count of in excess of four hundred and twenty-five 1 4 x 8 inch cartridges per one hundred pounds of the explosive.

13. A blasting explosive including as ingredients a sensitizer, a carbonaceous material containing asalt in intracellular relation and a nitrated salt in admixture with the impregnated carbonaceous material, the carbonaceous material being of low density, normally highly absorptive, and of such a character and in such quantity as to enable a cartridge count of in excess of four hundred and twenty-five 1 4 x 8 inch cartridges per one hundred pounds of theexplosive.

14. A blasting explosive including as ingredients a sensitizer, a carbonaceous material having a nitrated salt in intracellular relation and a nitrated salt in admixture with the carbonaceous material, the density, character and amount of the carbonaceous material being such that the density of the explosive with relation to its strength is substantially the same proportionally as that of black powder.

15, A blasting explosive including as ingredients a sensitizer, an explosive salt, an oxldizing salt and a carbonaceous material,

the carbonaceous ingredient supporting a.

salt in intracellular relation and being of low density, normally highly absorptive, and of such a character and in such quantity as to enable a cartridge count of in excess of four hundred and twenty-five 1 x 8 inch cartridges per hundred pounds of the explosive.

16. A blasting explosive including as ingredients a sensitizer, an explosive salt, an oxidizing salt, a salt containing water of crystallization and a carbonaceous material,

' the carbonaceous material supporting salt containing water of crystallization in intracellular relatlon and being of low density,

normally highly absorptive, and of sucha character and in such quantity as to enable a cartridge count of in excess of four hundred and twenty-five 1% x 8 inch cartridges per hundred pounds of the explosive.

17. A blasting explosive including as ingredients a sensitizer, ammonium nitrate, sodium nitrate, a salt containing water of crystallization and a carbonaceous material, the carbonaceous material supporting a salt ingredient of the explosive in intracellular relation and being of low density, normally highly absorptive, and of such a character and in such quantity as to enable a cartridge count of in excess of four hundred and twenty-five 1 4 x 8 inch cartridges per hundred pounds of the explosive.

18. A blasting explosive including as ingredients a sensitizer, ammonium nitrate, sodium nitrate, a salt containing water of crystallization and a carbonaceous material supporting salt ingredients of the explosive including salt containing water of crystallization in intracellular relation and being of low density, normally highly absorptive, and of such acharacter and in suchquantity as to enable a cartridge count of in excess of four hundred and twenty-five 1 x 8 inch cartridges per hundred pounds of the explosive.

19. A blasting explosive including as ingredients a sensitizer, an explosive salt, an oxidizing salt, a salt containing water of crystallization and a carbonaceous ingredient, the salts being in part supported in intracellular relation with respect to the carbonaceous ingredient and in part in mechanical admixture therewith and the carbonaceous ingredient being of low density, normally highly absorptive, and of such character and in such quantity as to enable acartridge count of in excess of four hundred and twenty-five 1% x 8 inch cartridges per one hundred pounds of the explosive.

20. A dynamite including as ingredients a sensitizer and wood, of the character of balsa wood, having an explosive salt in intracellular relation.

21. A dynamite including as ingredients, a sensitizer and wood, of the character of balsa wood, having-a nitrated salt and a salt containing water of crystallization in wood 5% to 30%, the carbonaceous material supporting" a salt ingredient of the explosive in intracellular relation.

24. A blasting explosive having a car- 5 tridge count equivalent to in excess'of fourhundred and twenty-five 1% x, 8 inch cartridges per one hundred pounds and including as ingredients nitroglycerine about 10.0%, ammonium nitrate about 47.0%, magnesium nitrate about 15.0%, sodium nitrate 10 about 12% and finely divided Wood of the character of balsa wood about 16.0%, the finely divided wood supporting magnesium nitrate in intracellular relation.

In testimony of which invention, I have 15 hereunto set my hand, at Kenvil, N. J., on this 1st day of November, 1927.

BUREN I. STOOPS,