Open Cut

NOx Fume Evolution from Hydrogen Peroxide Based Hybrid Mixtures

Open Cut » Drilling & Blasting

Published: April 18Project Number: C26025

Get ReportAuthor: Miguel Araos, Italo Onederra and Nathan Newton | The University of Queensland

The aim of this project was to develop new bulk explosive products that can completely eliminate NOx fume emissions. One of the key outcomes has been the development of explosives that use Hydrogen Peroxide (HP) as the main oxidiser together with a fuel phase that incorporates a sustainable and renewable fuel source. As part of the product development process, Hybrids of HP with other nitrates such as Ammonium Nitrate (AN) Calcium Nitrate (CN) and Sodium Nitrate (SN) have also been investigated and shown to perform as conventional non-ideal AN-based explosives.

HP/CN and HP/SN mixtures for example have shown advantages associated with more flexibility in the density range; and robustness leading to improved stability. Research with these new products opened specific questions about the potential formation of NOx given by the presence of nitrogen in the formulation, this is particularly the case for products such as HP/CN and HP/SN hybrids. These mixtures do not have a second source of nitrogen such as the NH4+ found in AN-based products.

The objective of this project was to quantify the NOx (or NO2) fumes produced by the detonation of HP-based hybrids products, where a portion of the HP is replaced by nitrates such as ammonium nitrate, calcium nitrate and sodium nitrate.

A blasting chamber was designed and commissioned to measure the production of NOx and other gases from a selected range of HP hybrid formulations. The commissioning of the blast chamber was completed in two stages by initially detonating small explosive charges and incrementally increasing to larger charge weights. Using small charges ensured the risk of damaging the chamber and any potentially unforeseen hazards were minimised. The primary objective was to monitor the post-blast gases and this required the chamber to be a closed system that could contain the overpressure generated from each blast.

A comprehensive experimental program was designed and implemented within a limited timeframe. HP-based hybrid gel formulations were prepared and tested at five different densities. In hybrid products part of the HP was replaced with AN, CN or SN. The HP-based product is a gel, with an emulsion explosive-like consistency. Two phases, oxidiser and fuel phases, are used to produce the product. These phases were mixed and then chemically gassed to achieve the target density. Samples were sensitised (gassed) and the gassing solution used was either KMnO4 1.0, 0.5% or 0.25% w/w. Control samples of ANFO and emulsion (single salt) were also tested for comparison purposes.  Samples and tests consisted of 100 grams of product in glass beakers with a 51 mm internal diameter. This charge size allowed a short ventilation time from the blast chamber and produced gas concentrations within the ranges of the gas monitor.

The HP-based gels were manufactured with an oxygen balance (OB) of 0.0±0.5. It was expected that CO presence would be minimal but testing showed otherwise. The CO presence was comparable to the AN-based products tested. Analysis showed that the presence of the plastic from the booster would have contributed to the CO measurements. Although only 12 grams of plastic is used to form the booster casing, the violent reaction caused during a detonation would result in the decomposition of the plastic material and will contribute to the gaseous products. Analysis also indicated that NH3 measurements may have come from the production of N2 which continues to react with excess hydrogen produced by the booster's plastic casing, forming NH3.

The formation of NOx was detected in HP/AN and HP/CN based hybrids explosives; and can be explained through basic analysis of the chemistry. HP-based (gel only) explosives, as expected, did not produce NOx. HP/SN hybrids did not produce NOx and although encouraging, it was difficult to explain. Analysis of the temperatures during the reaction taking place with HP/SN hybrids it was hypothesised that a lower temperature is achieved and thus prevented the formation of NOx. As part of future work it is important to extend testing in this area to fully understand the absence of NOx from these specific hybrid mixtures. It is also important to highlight the general trends observed which indicated a lower relative concentration of NOx in HP hybrid products when compared to the control AN based products (ANFO, emulsion and emulsion blend).

A key recommendation from this work is to transition to in situ trials as quickly as possible to further evaluate the performance of HP hybrids and any potential explosive rock interaction that could influence both detonation and the formation of expected gas by-products such as CO; and to a lesser extent NOx.  Based on current results, the HP/SN-based hybrid explosive seems to be an ideal candidate for field applications to reduce NOx fumes and due to the high energy but lower VOD, could be well suited to softer more friable ground conditions such as those found in pre-stripping and inter burden shots.


Health and safety, productivity and environment initiatives.


Open Cut

Safety, productivity and the right to operate are priorities for open cut mine research.

Recently Completed Projects

C19024Establishing Ecologically Sustainable Mine Water Release Criteria In Seasonally Flowing Streams

Extreme rainfall conditions in the Fitzroy Catchment over an approxi...

C25030Coal Mine Open Pit Final Void Closure And Relinquishment - Addressing Uncertainty In Coal Mine Environmental Planning

This report addresses uncertainties faced by coal mine operators whe...

C27046Estimation Of True Deformation Vector From Slope Radar Monitoring

Slope deformation radar monitors are now widely used in open cut coa...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C27004Improving Coal Flotation With Oscillatory Air Supply

This report provides detailed information on coal flotation with os...

C25018Improving Solids Recovery And Moisture Reduction In Ultrafine Coal Dewatering

This report provides detailed information on fine coal dewatering in...

C27028Lab Froth Flotation Testing Guide With Coal Quality

Correct outcomes from laboratory froth flotation testing in coal bor...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Recently Completed Projects

C26039Nanoporosity In Cokes: Their Origin, Control And Influence On CO2 Reactivity

This project using the outcomes of previous project C24060, examine...

C28063A Comprehensive Technical Review Of High-Efficiency Low-Emission (HELE) Pulverised Coal Combustion Technologies For Power Generation

Research and development has been undertaken worldwide to realise co...

C28064Carbon Structure Transformation During Coking Of Australian Coking Coals: Better Understanding The Coke Formation

Carbon structures of coke that are formed during the plastic layer a...

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C28076Selective Absorption Of Methane By Ionic Liquids (SAMIL) - Phase 2 Demonstration In A Packed Bed Reactor

An alternative approach to high temperature oxidation of ventilation...

C26004CFD Modelling Of Reverse Thermal Oxidisers For VAM Abatement - CFD Modelling Of Fixed-Bed RTO Devices

The project is part of a larger multi‐phase program of study a...

C27058Technological Assessment Of A Recycle Reactor For VAM Abatement

Underground coal mining emits high volumes of methane, diluted in ve...

Mine Site Greenhouse Gas Mitigation

Low Emission Coal Use

Step-change technologies aimed at reducing greenhouse gas emissions.

Recently Completed Projects

C17060BGasification Of Australian Coals

Four Australian coals were trialled in the Siemens 5 MWth pilot scale ga...

C17060AOxyfuel Technology For Carbon Capture And Storage Critical Clean Coal Technology - Interim Support

The status of oxy-fuel technology for first-generation plant is indicate...

C18007Review Of Underground Coal Gasification

This report consists of a broad review of underground coal gasification,...

Low Emission Coal Use

Mining And The Community

The relationship between mines and the local community.

Recently Completed Projects

C16027Assessing Housing And Labour Market Impacts Of Mining Developments In Bowen Basin Communities

The focus of this ACARP-funded project has been to identify a number...

C22029Understanding And Managing Cumulative Impacts Of Coal Mining And Other Land Uses In Regions With Diversified Economies

The coal industry operates in the context of competing land-uses that sh...

C23016Approval And Planning Assessment Of Black Coal Mines In NSW And Qld: A Review Of Economic Assessment Techniques

This reports on issues surrounding economic assessment and analysis ...

Mining And The Community


National Energy Research,Development & Demonstration Council (NERDDC) reports - pre 1992.

Recently Completed Projects

1609-C1609Self Heating of Spoil Piles from Open Cut Coal Mines

Self Heating of Spoil Piles from Open Cut Coal Mines

1301-C1301Stress Control Methods for Optimised Development...

Stress Control Methods for Optimised Development and Extraction Operations

0033-C1356Commissioned Report: Australian Thermal Coals...

Commissioned Report: Australian Thermal Coals - An Industry Handbook