Addressing a commonly held belief that single salt emulsions deliver greater energy in a blast, Pathak says evidence shows there is little, if any, difference between single and double salt emulsions in this respect.
“We studied the data produced by various alternative single salt emulsion systems in the market and found that it was, in fact, very difficult to compare results, as the software used is not common across users,” Pathak says. “The most effective way to test is in the field, using different suppliers’ products in the same blasting conditions.”
Reactive ground
Pathak also says blasting in reactive ground poses challenges where explosives can degrade in the blasthole or even detonate prematurely.
Having only half the ammonium nitrate of a single salt product, she says a dual salt emulsion is more resistant to reactive ground conditions.
“Adding to this resistance is used oil as a fuel agent in emulsion, as well as BME’s specialized emulsifier,” Pathak says. “Using this emulsion with added urea, blasters gain a safe window to load and shoot.”
Adding urea
Pathak says the quantity of urea also needs to be determined with scientific accuracy, as too much urea can reduce the energy of a blast.
Based on lab testing, BME says adding 7.5 percent urea to the emulsion reduces its energy values by about 6 percent.
Parting thoughts
In summary, Pathak says the chemical benefits of double salt emulsions include its stability, its resistance to crystallization, its oxygen balance and its lower risk of nitrate leaching.
As a case study demonstrating these factors, BME shipped 4,000 metric tons of emulsion to the island of St. Helena for use in a major civil engineering project. The emulsion faced up to 10 pumping cycles, extended periods of transportation on road and sea, and varied climatic conditions.
“Even after enduring these conditions, the product performed on-site in line with customer expectations,” Pathak says. “This showed that a double salt emulsion explosive can enhance the productivity of mining operations, including other sectors, while delivering the environmental benefits that miners are looking for.”
Related: Economic impact study illustrates benefits of commercial explosives
Information for this article courtesy of BME.
