Modified blasting agent

Abstract

The present invention relates generally to an explosive composition comprising an aqueous emulsion of: an oxidizer component, a hydrocarbon fuel component containing emulsifier, and a bulking agent being a fuel-type waste material in a solid particulate form substantially lacking rough surfaces and sharp edges. Preferably the composition is of an ammonium nitrate based emulsion and a pelletised bulking agent. It also involves a method of providing an explosive composition to a blast site using a conventional mobile processing unit (MPU), being a truck having separate compartments adapted for holding fuel oil, dry ammonium nitrate prill, and ammonium nitrate based emulsion, where a compartment instead holds particulate waste material. It also concerns a method of blasting soft and wet ground, which comprises injecting into one or more blast holes in the soft and wet ground a sufficient quantity of the composition, and then setting off the composition.

1 . An explosive composition comprising an aqueous emulsion of
 an oxidizer component,   a hydrocarbon fuel component containing emulsifier, and   fuel-type waste material in a solid particulate form lacking rough surfaces and sharp edges sufficiently so as to not promote crystallisation of the emulsion.   
     
     
         2 . The composition of  claim 1 , wherein the presence of the waste material alone does not provide sensitisation to the emulsion to permit an explosion; an explosion being permitted by the later addition of a sensitisation component to the composition. 
     
     
         3 . The composition of  claim 2 , wherein the sensitisation component is a density reducing agent. 
     
     
         4 . The composition of  claim 1 , wherein the oxidizing agent is selected from one or more of ammonium nitrate, sodium nitrate, or calcium nitrate. 
     
     
         5 . The composition of  claim 4 , wherein the oxidizing agent is ammonium nitrate. 
     
     
         6 . The composition of  claim 3 , where the density reducing agent is a salt of an alkali metal nitrite and an acid, which generate nitrogen gas when combined. 
     
     
         7 . The composition of  claim 1 , wherein the composition of the fuel type waste material is selected from any one or more of: plastics material, rubber, paper, cardboard, wax material, and commingled plastic waste material. 
     
     
         8 . The composition of  claim 6 , wherein the density of the composition is reduced to between 0.80 and 1.15 g/cm 3  by the addition of the density reducing agent. 
     
     
         9 . The composition of  claim 1 , wherein the particulate waste material is in the form of pellets substantially lacking rough surfaces and sharp edges. 
     
     
         10 . The composition of  claim 1 , wherein the particulate waste material has an average particle size of about 2 to 3 mm. 
     
     
         11 . The composition of  claim 1 , wherein the waste material comprises from 1% to 50% by weight of the total composition. 
     
     
         12 . The composition of  claim 11 , wherein the waste material comprises from 10 to 40% by weight of the total composition. 
     
     
         13 . The composition of  claim 1 , wherein the fuel-type waste material in a solid particulate form has a Rod Rating test (as described herein) value of 6 or higher. 
     
     
         14 . A method of providing an explosive composition to a blast site having one or more blastholes for receiving the composition, by means of a conventional mobile processing unit (MPU), said unit comprising a truck having separate compartments adapted for holding (a) fuel oil, (b) dry ammonium nitrate prill, and (c) ammonium nitrate based emulsion, and said unit having means for mixing two or more of the components from compartments (a), (b) and (c) together and injecting the resulting mixture in a blasthole,
 characterised in that compartment (b) instead holds particulate waste material, and   a density reducing agent is added to the mixture from compartments (a), (b) and (c) just prior to it being injected into a blast hole by an auger on the MPU,   and wherein the composition is as defined in  claim 1 .   
     
     
         15 . The method of  claim 14 , wherein the mixture is injected into the blasthole by means of an auger. 
     
     
         16 . A method of blasting soft and wet ground, which comprises injecting into one or more blast holes in the soft and wet ground a sufficient quantity of the composition according to  claim 1 , and then setting off the composition. 
     
     
         17 . The method of  claim 16 , wherein the composition is injected into the blast holes by means of a conventional mobile processing unit, said unit comprising a truck having separate compartments adapted for holding (a) fuel oil, (b) dry ammonium nitrate prill, and (c) ammonium nitrate based emulsion, and said unit having means for mixing two or more of the components from compartments (a), (b) and (c) together and injecting the resulting mixture in a blasthole,
 characterised in that compartment (a) instead holds particulate waste material, and   a density reducing agent is added to the mixture from compartments (a), (b) and (c) just prior to it being injected into a blast hole by an auger of the MPU.   
     
     
         18 . The method of  claim 17 , wherein the mixture is injected into the blasthole by means of an auger.