Alternative and Sustainable Explosive Formulations to Eliminate Nitrogen Oxide Emissions

This technical report describes the technology of a novel mining explosive that was developed under ACARP project C23029 with the potential to solve the issue of Nitrogen Oxide (NOx) fumes after blasting. Post blast fumes are toxic nitrogen oxides which are a direct product of the detonation process and they can be easily identified as the resultant yellow, orange to purple post blast clouds after blasting. These nitrogen oxides are produced primarily by the presence of nitrogen (N) in the explosive. Upon detonation, N transforms into nitrogen monoxide (NO), which then continues its oxidation to NO2 or a mixture of nitrogen oxide (NOx) as the blast fumes mix with air. Nearly 100% of explosives used in mining applications around the world use ammonium nitrate (AN) as the main oxidising agent, so the possibility of having NOx fumes after blasting is always present.

In order to control NOx fumes from blasting, mining companies, union representatives and the regulator have met to address the problem. As a result, guidelines on how to prevent and minimise the risk of NOx fume emissions have been issued. Notwithstanding that, NOx fume incidences continue to occur. This is attributed to the fact that administrative controls are prone to degradation due to human intervention.

In 2013 a project proposal was submitted to ACARP to investigate a more disruptive technological solution to eliminate the NOx hazard. The project involved researching and developing an explosive without the use of AN as the main oxidising agent. This explosive would replace AN with Hydrogen Peroxide (HP) which would eliminate Nitrogen in the formulation, making it impossible to produce NOx fumes. ACARP commenced funding the first year of project C23029 in April of 2014 and set the following milestones:

· Demonstrate that the new HP based products detonate in a variety of different densities and diameters without any risk of NOx production;

· Demonstrate a feasible system to manufacture and deliver the blasting agent;

· Demonstrate that this new explosive product could adequately break and fragment rock and match the performance characteristics of conventional AN based products; and

· Conduct a business case for the further development and implementation of this new explosive product.

The authors of this report believe that the above milestones have been satisfactorily achieved. This final report provides a comprehensive description of the following:

· Development and description of the new explosive technology (formulation, thermodynamic properties, detonation properties such as velocity of detonations (VOD), manufacturing methods, safety);

· Description of the prototype manufacturing system to make the blasting agent and also the delivery of the explosive. The complete process conducted in one unit;

· Rock breakage performance analysis from single hole and multiple hole tests; and

· Business case regarding manufacture and delivery strategies of this novel explosive product.

There has been further research conducted in this area.  Please review the abstract for project C25005 for more information.