Explosive compositions with reduced fume

Abstract

Explosive compositions including coated urea and an explosive including ammonium nitrate and fuel oil are provided. The explosive compositions can generate reduced levels of nitrogen oxide upon detonation. Methods of loading a blasthole with the explosive compositions and methods of reducing post-blast nitrogen oxide are also provided.

1 . An explosive composition comprising:
 an explosive comprising ammonium nitrate and fuel oil; and   coated urea.   
     
     
         2 . The explosive composition of  claim 1 , wherein the ratio of the explosive to the coated urea is from about 1:1 to about 3:1. 
     
     
         3 . The explosive composition of  claim 1 , comprising from about 0.5 weight percent (wt %) to about 30 wt % coated urea. 
     
     
         4 . The explosive composition of  claim 1 , wherein the coated urea is in the form of prills or granules. 
     
     
         5 . The explosive composition of  claim 1 , wherein the coated urea comprises a water resistant coating. 
     
     
         6 . The explosive composition of  claim 5 , wherein the water resistant coating is selected from at least one of a polymer, a wax, a stearate, a silicone polymer, a hydrophobic clay, a hydrophobic silica, a hydrophobic and particulate solid, a dimer acid, and an oligomeric acid. 
     
     
         7 . The explosive composition of  claim 5 , wherein the water resistant coating is a polymer selected from at least one of polyethylene terephthalate (PET), low-density polyethylene (LDPE), high-density polyethylene (HDPE), low-density polypropylene (LDPP), high-density polypropylene (HDPP), a polyamide, a polyester, polylactic acid, acrylonitrile butadiene styrene (ABS), and polystyrene. 
     
     
         8 . The explosive composition of  claim 1 , wherein the coated urea comprises unreacted urea. 
     
     
         9 . The explosive composition of  claim 1 , further comprising an emulsion. 
     
     
         10 . The explosive composition of  claim 9 , comprising from about 10 wt % to about 60 wt % emulsion. 
     
     
         11 . The explosive composition of  claim 1 , wherein the explosive composition is water resistant. 
     
     
         12 . The explosive composition of  claim 1 , wherein the explosive composition is resistant to humid conditions. 
     
     
         13 . The explosive composition of  claim 1 , wherein the explosive composition is resistant to warm temperatures. 
     
     
         14 . The explosive composition of  claim 1 , wherein the explosive composition is resistant to liquefaction. 
     
     
         15 . The explosive composition of  claim 1 , wherein upon detonation of the explosive composition, production of post-blast nitrogen oxide is reduced. 
     
     
         16 . A method of loading a blasthole with an explosive composition, the method comprising:
 mixing an explosive comprising ammonium nitrate and fuel oil (ANFO) with coated urea to form the explosive composition; and   delivering the explosive composition to the blasthole.   
     
     
         17 . The method of  claim 16 , further comprising adding an emulsion to the explosive composition. 
     
     
         18 . The method of  claim 16 , further comprising detonating the explosive composition, wherein production of post-blast nitrogen oxide is reduced. 
     
     
         19 . A method of reducing post-blast nitrogen oxide, the method comprising:
 mixing an explosive comprising ammonium nitrate and fuel oil with coated urea to form an explosive composition; and   delivering the explosive composition to a blasthole.   
     
     
         20 . The method of  claim 19 , further comprising adding an emulsion to the explosive composition.