Resumen
Described is a method for sensitizing in situ aqueous explosives before charging the mine holes. The method comprises the formation of an emulsion or dispersion gas-in-liquid from a low sensitivity or non explosive matrix product which consists of a liquid mixture in solution, emulsion or suspension of oxidant in fuel, and a gas. The density of the final explosive product can be varied as a function of the gas flow rate and can be controlled before introducing it into the hole. The installation comprises a tank (1) with the matrix product, a gas reserve (10), a mixture (5), a pump (3) and a gas flow rate regulating device (8) and optionally a tank (2) with a gas bubble stabilizing agent, a dosing pump (4) and a flow meter (7).
Reivindicaciones
1. A procedure for "in situ" sensitization of water based explosives, characterized in that it comprises (i) the transport to the borers loading place of a non explosive or low sensitivity base product composed by an aqueous liquid mixture which comprises oxidants and fuels, in solution, in emulsion or in suspension, optionally together with sensitizing and thickening agents, and (ii) the sensitization of said base product before its loading in the borers, characterized in that: such sensitization is performed by mixing said base product with a gas towards a mixer, by the formation of a suspension or an emulsion of gas in liquid; and the density of the sensitized explosive is adjusted by the regulation of the gas flow. 2. A procedure according to claim 1, characterized in that such base product comprises between 30% and 90% by weight of oxidants. 3. A procedure according to claim 1, characterized in that such base product comprises an oxidant selected from the group formed by nitrates, chlorates and perchlorates of ammonium, alkaline and alkaline-earth metals as well as mixtures thereof. 4. A procedure according to claim 1, characterized in that such base product comprises between 1% and 20% by weight of fuels. 5. A procedure according to claim 1, characterized in that such base product comprises a fuel selected from the group formed by aromatic hydrocarbons, aliphatic hydrocarbons, oils, petrol derivatives, vegetable occurring derivatives, finely divided metallic fuels, and their mixtures. 6. A procedure according to claim 1, characterized in that such base product comprises between 0.5% and 40% by weight of sesitizing agents. 7. A procedure according to claim 1, characterized in that such base product comprises a sensitizing agent selected from the group fromed by alkylamine nitrates, alkanolamine nitrates, and their mixtures. 8. A procedure according to claim 1, characterized in that such base product comprises between 0.1% and 5% by weight of thickening agents. 9. A procedure according to claim 1, characterized in that such base product comprises a thickening agent selected from the group formed by products derived from seeds, biosynthethic products and their derivatives and synthetic polymers. 10. A procedure according to claim 1, characterized in that such gas is selected from the group formed by air, nitrogen, oxygen and carbon dioxide. 11. A procedure according to claim 1, characterized in that the volumetric ratio between the gas and the base product is comprised between 0.05 and 5. 12. A procedure according to claim 1, characterized in that it also includes the addition of a stabilizing solution of the gas bubbles. 13. A procedure according to claim 12, characterized in that such stabilizing solution of the gas bubbles is selected from the group formed by surface-active solutions or dispersions of the type derived from amines of fatty acids, proteins and modified guar gum. 14. An installation for "in situ" sensitization of water based explosives, according to claim 1, characterized in that it contains at least: a tank for the storage of the base product; a gas reserve; a mixer; a pump which connects the tank of the base product to the mixer; and a gas flow regulating device. 15. An installation according to claim 14, characterized in that it also contains a tank for the storage of a stabilizing solution of the gas bubbles and a doser pump. 16. An installation according to any of claims 14 or 15, characterized in that it is located in a loading truck. 17. An installation according to any of claims 14 to 16, characterized in that the mixer operates continuously. 18. An installation according to any of claims 14 to 17, characterized in that the mixer is a dynamic type. Amended claims under Art. 19.1 PCT Basis for the new claims Claim 1 replaces claim 1 as originally filed. Claims 2 to 18 remain unchanged. Claim 1, as now worded, points out clearly the essential aspects of the invention subject to this patent application. New claim 1 is based on the original claim 1 combined with what is worded, for instance, in page 4, lines 5-7, from page 5, line 35 to page 6, line 3, and in the Example that goes with the description of this patent application. Comments to the International Search Report 1. 1. The documents cited in the International Search Report, henceforth (IBI), were the following: D1:EP 0 203 230 A1 D2:CA 2 136 572 A D3: EP 0 322 097 A1 D4: EP 0 403 091 A1 D5: US 4 287 010 A1 D6: EP 0 131 355 A1 2. 2. The present invention faces the problem of developing a procedure for "in situ" sensitization of water based explosives obtained from a non-explosive or low sensitivity base product which allows to easily modify the density of the explosive as well as the size of the gas bubbles. The different solutions furnished by the prior art to sensitize "in situ" explosives which might be obtained from low sensitivity base products comprise: a) the mixture with low density particled nitrates as well as mixtures thereof with mineral oils (ANFO), b) the mixture with low density particles (hollow microspheres), or c) the generation of bubbles by means of a chemical reaction. Solutions a) and b) allow to control the density of the explosives before filling up the borers, whereas in solution c) the chemical reaction the gas generates is produced after the borers have been filled up whereby there is no chance to adjust the density of the explosive in case it is not right. However, the solution proposed in this invention lies in sensitizing "in situ" a non-explosive or low sensitivity base product, water based, by means of a procedure characterized in that: a) there is a dosage and a mixture of suitable quantities of: i) a non-explosive or low density base product formed by a water base liquid mixture which comprises oxidants and fuels together with, optionally, sensitizing and thickening agents; and ii) a gas, giving as a result a suspension or emulsion of liquid gas; b) the density of the sensitized explosive is adjusted by the regulation of the gas flow. 3. None of the documents cited in the IBI deprives the invention subject to this patent application of novelty or of inventive merit, as claimed now ["in situ" sensitization of explosives by means of the incorporation of a gas and a density control of the explosive by regulating the gas flow], since such documents seem to prove that, before filing this patent application, there was knowledge of: the possibility of sensitizing explosives "in situ" by adding low density particles (D1 and D3), or by chemical gasification (D2); and the possibility of sensitizing explosives in plant by incorporating a gas (D5 and D6). On the other hand, D3 and D4 seem to refer to the preparation of the "base product" before its sensitization.
