US 2016.0052835A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2016/0052835 A1 KLUNKER et al. (43) Pub. Date: Feb. 25, 2016

(54) DETONATOR-SENSITIVE ASSEMBLED (30) Foreign Application Priority Data BOOSTER CHARGES FOR USE IN BLASTING ENGINEERING AND THE USE Nov. 14, 2012 (DE) ...... 10 2012 110955.9 THEREOF (71) Applicant: EST ENERGETICS GMBH, Rothenburg (DE) Publication Classification (51) Int. Cl. (72) Inventors: Jirgen KLUNKER, Niesky (DE): C06B 23/00 (2006.01) Konrad ZIEGLER, Bernburg Saale F42D3/00 (2006.01) (DE) C06B 25/34 (2006.01) (73) Assignee: EST ENERGETICS GMBH, (52) U.S. Cl. Rothenburg (DE) CPC ...... C06B 23/003 (2013.01); C06B 25/34 (2013.01); F42D 3/00 (2013.01) (21) Appl. No.: 14/442,197 (22) PCT Fled: Nov. 12, 2013 (57) ABSTRACT PCT NO.: PCT/EP2013/0736.58 (86) This invention relates to detonator-sensitive assembled S371 (c)(1), booster charges for use in blasting engineering. The booster (2) Date: May 12, 2015 charge comprises nitroalkane and a cavity-forming agent. US 2016/0052835 A1 Feb. 25, 2016

DETONATOR-SENSITIVE ASSEMBLED dispersed microspheres. The microspheres can be hollow BOOSTER CHARGES FOR USE IN glass microspheres, resin beads, ceramic beads, etc. BLASTING ENGINEERING AND THE USE 0008 Further disclosed, in U.S. Pat. No. 4,334,476A, is an THEREOF initial explosive charge for granular or liquid explosives, with 0001. The invention concerns detonator-sensitive an interior channel to hold the ignition device, whereby the assembled booster charges for use in blasting engineering. interior channel exhibits a small wall thickness so as to 0002 Insensitive, non-toxic and inexpensive explosives, improve the detonation. This ensures the separation of the mostly based on ammonium nitrate, are preferentially used in liquid explosive and the ignition device. civil blasting applications. In Salt mining or tunnel driving, 0009 Finally, U.S. Pat. No. 3,797.392 A discloses micro for example, so-called pumping explosives are used in addi spheres, used for the sensitization of liquid explosives. These tion to the long familiar ANFO. Pump explosives are differ microspheres, such as hollow glass spheres, ceramic micro entiated into emulsion explosives and Suspension explosives spheres or silicon carbide, are dispersed in the liquid explo (slurries, explosive slurries). sive right away and Subsequently ignited. The use of open 0003 ANFO (Ammonium Nitrate Fuel, trade name e.g. pored polyurethane foams is described as well. ANDEX) is a mixture of porous ammonium nitrate and min 0010. Therefore, the task of the invention is to specify an eral oil or diesel oil (fuel oil), which is used in the mining IG detonator that can be used safely, is inexpensive and safe industry as a safe-to-handle explosive. to manufacture, and can be handled with no risk to health. 0004. In addition, if not sufficient for safe ignition, these 0011. The task is solved with a detonator-sensitive booster explosives require so-called primary explosives in conjunc charge according to Claim 1. Advantageous embodiments are tion with detonator-sensitive assembled initiation charges specified in the dependent claims. (boosters, amplifier charges or primers). Primary explosives 0012. According to the invention, a detonator-sensitive can be found in commercial detonators. Primary explosives booster charge comprising a mixture including a nitroalkane are characterized by high sensitivity to friction, shock, impact and a cavity-forming means, as well as a slot for an ignition and heat. Mercury fulminate, for example, can already be device, is Suggested. detonated by heating to 160°C. (detonating cord) or by a 2 kg 0013 Surprisingly, it was found that nitroalkanes are well drop hammer falling from a height of 4 cm. Initial detonation Suited for use in detonator-sensitive booster charges. with blasting caps was invented in 1862 by Alfred Nobel. 0014 Nitroalkanes can be activated chemically, e.g. by Important primary explosives are mercury fulminate, lead addition of amine, and/or mechanically via the creation of azide, silver azide, silver acetylide, silver fulminate, diazod Smallhollow spaces or gas-filled cavities (foaming), i.e. they initrophenol, lead picrate (trinitrophenol lead), lead styphnate become detonator sensitive and behave like volatile explo (lead trinitroresorcinate), tetracene, nickel hydrazine nitrate sives. In order to maintain a uniform distribution of the cavity (NHN), hexamethylene triperoxide diamine (HMTD). formers, the addition of a thixotropic agent is indicated. Such acetone peroxide (DADP, TATP or APEX), 3-nitrobenzene mixtures are disclosed in U.S. Pat. No. 3,713,915. diazonium perchlorate, mercury azides, tetraamine copper 0015 Nitromethane mixtures, which are produced with (II) chlorate (TACC) and copper acetylide. commercially available hollow glass microspheres (glass 0005 Pressed cylindrical explosive devices made of tetryl, microballoon, GMB) and which detonate at more than 6000 trinitrotoluene, phlegmatized (reduction of sensitivity) hexo m/s and are detonator-sensitive, are also known (Presles et al. gen, pentaerythritol tetranitrate (PETN), picric acid and other Shock Waves, April 1995, Volume 4, Issue 6, p. 325-329). explosives are usually used as detonator-sensitive assembled 0016. In one embodiment of the invention, the detonator booster charges, also referred to as initial gain detonator or IG sensitive booster charge is made of a liquid-impermeable detonator. Common to all these Substances is a greater sensi material. This prevents leaking of the nitroalkane. tivity to the initial pulse than that of the explosive of the main 0017. In a further embodiment of the invention, the deto charge (e.g. ANFO, cast TNT, powdery explosives). Primer nator-sensitive booster charge exhibits a concave curvature cartridges of gelatinized explosives are often used in rock arranged on the opposite side of the slot for the ignition blasting as an additional amplification charge to initiate the device. In the sense of the present invention, a concave cur main charge of powdery explosives or emulsion explosives. Vature is a conical or hemispherical curvature on the direction The weight and the shape of the IG detonator are calculated so of the center of the booster charge. With the concave curva that, at detonation, a pulse is produced that ensures the trig ture the effect of a hollow charge is achieved, which results in gering of the detonation of the main charge and the desired an increased detonation velocity. The curvature causes the detonation behavior. The initiation of the IG detonator is energy released by the detonation to be focused in this direc triggered by a blasting cap, an electric detonator or a NE tion. For this reason the booster charge is inserted with the igniter (non-electric igniter). concave curvature in the direction of the main charge. The 0006. The problem with the IG detonators used to date is advantageous design with concave curvature significantly that they either consist of long term no longer available mili increases the effectiveness of the inventive booster charge. tary explosives (pressed TNT, cast Composition B, etc.), or 0018. In a further embodiment of the invention, the con that classic primer cartridges made of gelatinous explosives cave curvature exhibits a metallic coating. The metallic coat (dynamite Successors on the basis of blasting oil) are used, ing can be made of aluminum and applied to the Surface of the which becomes problematic in the long term. Besides the concave curvature by spraying, steaming or as a metallic film. increased health hazard from nitric acid ester, the compli The metallic coating of the concave curvature affects an cated and hazardous production and the associated high cost intensifying initial pulse in a specified direction. are a significant issue. 0019. The concave curvature with a metallic coating is of 0007 U.S. Pat. No. 3,902,933 A discloses an initial explo particular importance for achieving a high chemical imple sive charge for detonation of nitromethane. The initial explo mentation rate, in which the implementation process comes sive charge is formed by a polyurethane foam containing very close to the theoretical value. This significantly reduces US 2016/0052835 A1 Feb. 25, 2016

the level of harmful substances in the borehole column charge product that, due to the gas-phase nitration of propane, is for the commercial explosives to be activated. available for the long term—even when recycled military 0020. In another embodiment of the invention, the ignition explosives become scarce. device is a blasting cap, a detonating cord or a non-electric 0035) Nitromethane is also not a classic explosive, which detonator. makes transport and storage inexpensive, and is of storage 0021. In a further embodiment of the invention, the deto class 3 (flammable liquids). In addition, nitromethane has low nator-sensitive booster charge exhibits a suitable wall thick toxicity: LD50 oral rat: 940 mg/kg, WHC 2. ness. This ensures a secure ignition transfer from the cap or 0036. It is also advantageous that, in the event of damage, the cord to the nitroalkane mixture. The wall thickness is the inventive detonator-sensitive booster charges “deacti dependent on the material of the wall as well as the mixture vate themselves by complete volatilization of the used. nitromethane into the air. 0022. In a further embodiment of the invention, the 0037. The inventive detonator-sensitive booster charges nitroalkane is selected from a group with 1 to 3 carbon atoms. are designed to be absolutely waterproof and temperature 0023. In a further embodiment of the invention, the resistant. There is no exudation of fluids. Thus, because there nitroalkane is nitromethane. are no chemical reactions between the mixture components, 0024. In a further embodiment of the invention, the cavity the inventive detonator-sensitive booster charges in a mixture forming means is configured as a hollow glass microsphere. with Aerosiland GMBs have a practically unlimited shelflife. 0038 Moreover, the manufacturing of the inventive deto 0025 Inafurther embodiment of the invention, the cavity nator-sensitive booster charges invention does not require forming means is configured as a hollow glass microsphere dangerous melting processes. In addition, no long waiting with a grain size of 20-200 um, preferably 40-150 um, par period is necessary after mixing of the components, which is ticularly preferred 80-120 um. why manufacturing can be easily and safely (away from 0026. In a further embodiment of the invention, the cavity people) automated. forming means is configured as a hollow glass microsphere 0039. It is also important that the components in the mix with a grain size of substantially 100 um. ture are not explosive materials, necessitating only minor 0027. In a further embodiment of the invention, the mix ture includes Aerosil. In this context Aerosil is a fumed silica. storage and transportation costs. 0028. In a further embodiment of the invention, the mix 0040 Preferred embodiments of the invention result from ture exhibits 1.5-10 weight%, preferably 3-8 weight%, par combinations of the claims or individual features thereof. ticularly preferred 5-7 weight % Aerosil, 0.2-10 weight %, 0041. In the following, the invention will be described in preferably 0.5-5 weight %, particularly preferred 0.8-2 detail with reference to several design examples. The design weight% hollow glass microspheres and 85-98.3 weight%, examples are intended to describe the invention without lim preferably 89-95, particularly preferred 91-93 weight % iting it. nitromethane. 0042. In one design example of the invention, pure ammo 0029. In a further embodiment of the invention, the mix nium nitrate and ANFO (in each case with 13 g of the inven ture exhibits 6.5 weight% Aerosil, 1 weight% hollow glass tive composition in a cylindrical booster charge) with the microspheres with a grain size of Substantially 100 um and following composition were brought to a detonative reaction: 92.5 weight% nitromethane. 6.5% Aerosil, 1% GMBs ca 100 um, 92.5% nitromethane. 0030. In a further embodiment, the mixture also comprises 0043. In the process, detonation velocities of ca. 4500 at least one oxygen-containing compound selected from the m/were measured, which indicates adequate Suitability of the nitrates group to increase the oxygen balance. In one design mixture for the initiation of non-detonator-sensitive commer of the embodiment, the oxygen-containing compound is cial explosives to initiate larger amplifier charges and for ammonium nitrate. direct use for special blasting (avalanches, ice, etc.). 0031. The use of the inventive detonator-sensitive booster 1. Detonator-sensitive booster charge for use in blasting charge is also the Subject matter of the invention. engineering comprising a mixture including a nitroalkane and 0032. The inventive detonator-sensitive booster charges a cavity-forming means as well as a slot for an ignition device. are used to initiate non-detonator-sensitive commercial 2. Detonator-sensitive booster charge according to claim 1, explosives, preferentially in boreholes on the surface and characterized in that the booster charge is made of a liquid below ground, to initiate larger amplifier charges and for impermeable material. direct use for special blasting (avalanches, ice etc.). In par 3. Detonator-sensitive booster charge according to claim 1, ticular, the inventive detonator-sensitive booster charges are characterized in that the booster charge exhibits a concave used for the initiation of explosives in mining applications curvature arranged on the opposite side of the slot for the and tunnel construction. ignition device. 0033. In doing so the inventive detonator-sensitive booster 4. Detonator-sensitive booster charge according to claim3, charges exhibit the following advantages: characterized in that the concave curvature exhibits a metallic 0034. Detonation velocities of ca. 6000 m/s are achieved coating. with the inventive detonator-sensitive booster charges, allow 5. Detonator-sensitive booster charge according to claim 1, ing the detonation of non-detonator-sensitive explosives. characterized in that the ignition device is a blasting cap, a Moreover, no nitroaromatics, which are suspected to be car detonating cord or a non-electric detonator. cinogenic, and no nitroesters, which are physiologically 6. Detonator-sensitive booster charge according to claim 1, problematic due to possible vasodilation, are formed when characterized in that the nitroalkane is selected from a group the detonator-sensitive booster charges are used. Health prob with 1 to 3 carbon atoms. lems among users can thus be avoided. In addition, the inven 7. Detonator-sensitive booster charge according to claim 1, tively preferred nitroalkane nitromethane is an inexpensive characterized in that the nitroalkane is nitromethane. US 2016/0052835 A1 Feb. 25, 2016

8. Detonator-sensitive booster charge according to claim 1, characterized in that the cavity-forming means is configured as a hollow glass microsphere. 9. Detonator-sensitive booster charge according to claim8, characterized in that the cavity-forming means is configured as a hollow glass microsphere with a grain size of 20-200Lum, preferably 40-150 lum, particularly preferred 80-120 Lum. 10. Detonator-sensitive booster charge according to claim 1, further comprising a fumed silica. 11. Detonator-sensitive booster charge according to claim 1, characterized in that the mixture exhibits 1.5-10 weight%, preferably 3-8 weight%, particularly preferred 5-7 weight% Aerosil, 0.2-10 weight%, preferably 0.5-5 weight%, particu larly preferred 0.8-2 weight% hollow glass microspheres and 85-98.3 weight %, preferably 89-95, particularly preferred 91-93 weight% nitromethane. 12. Detonator-sensitive booster charge according to claim 1, characterized in that the mixture exhibits 6.5 weight % Aerosil, 1 weight% hollow glass microspheres with a grain size of substantially 100 um and 92.5 weight% nitromethane. 13. Detonator-sensitive booster charge according to claim 1, further comprising an oxygen-containing compound selected from the nitrates group. 14. A method comprising using a detonator-sensitive booster charge to initiate non-detonator-sensitive commercial explosives, preferentially in boreholes on the surface and below ground, to initiate larger amplifier charges and for direct use for special blasting. 15. A method according to claim 14, wherein using the detonator-sensitive booster charge is for the initiation of explosives in mining applications and tunnel construction. k k k k k