What to consider when selecting emulsion over dry bulk explosives

While ammonium nitrate fuel oil (ANFO) remains one of the most cost-effective and widely used bulk explosives in the mining industry due to its simplicity, reliability, and performance in dry conditions, it does have limitations in certain environments. Moisture from rain, groundwater, or condensation can compromise ANFO’s effectiveness, making it less suitable for use in wet boreholes.

In such conditions, emulsion explosives offer an effective alternative, maintaining blast schedules and delivering consistent results across a wider range of geological settings. Emulsion explosives are highly valued for their stability, safety, and performance, particularly under wet conditions. The biggest benefits include highly optimised fragmentation and minimised overbreak while still delivering exceptionally high energy output.

Since the fuel, oxidiser, and water components are uniformly mixed, the explosive remains stable even if a hole fills with water. The emulsion is pumped in at the right viscosity to fill the hole properly and avoid leaks or energy loss, which helps ensure a more consistent blast result. By ensuring strong contact to the rock, the emulsion maintains pressure and energy direction, improving overall blast efficiency and reducing the need for secondary blasting.

This level of control is especially important in deep or irregular boreholes, where gaps or voids can reduce effectiveness or cause misfires.

Other benefits of emulsion explosives include:

• Safety

Worker safety and shaft stability is always a primary concern when dealing with explosives. The emulsion mixture only becomes a true explosive after sensitising gas is introduced at the borehole. Until that moment, shock, friction, and stray sparks cannot propagate a blast. Crews can therefore work without the tension that surrounds live cartridges.

• Efficiency

Emulsions can help improve blasting efficiency. With pre-packaged explosives, planners have to choose the closest cartridge size, even if it doesn’t match the shape of the stope. Pumped emulsions work more like grout, where the operator can measure and inject the exact right amount based on rock characteristics. This can reduce wasted space and makes it easier for engineers to get the optimal rock size for the crusher.

• Fragmentation

Because the explosive charge completely fills the diameter of the blast hole, with no gaps between the explosive and the rock wall, a tighter fragmentation is produced with flatter muck piles. As a result, load-and-haul fleets may spend less time handling rock fragments too large to be managed efficiently by standard equipment.

• Costs

Emulsion costs more than ANFO upfront, but a cleaner underground blast means less damage to the surrounding rock, and less shotcrete is needed as support. This speeds up the time between drilling and bolting.

• Regulatory requirements

Pumpable emulsions often carry less regulatory complexity for mining companies and logistics management partners such as Mining and Energy Acuity (MEA) to transport and store the material. While ANFO is traded under full Class 1 hazardous materials restrictions, base emulsions ship as Class 5.1 oxidizers, not as explosives.

This means that blasting intermediates can be moved alongside other materials, reducing the number of trips required, and cutting down on both shaft and tramming time, while also enabling extended storage underground. This single classification distinction significantly simplifies permit requirements.

By embracing emulsion explosives within a framework of safety, effectivity, and efficiency, mining operations can blast smarter and safer.

MEA has spent years defining a full-circle explosives management service solution. Our services include procurement, logistics, warehousing, and technical assistance, ensuring that emulsion explosives are delivered and managed efficiently and safely. MEA's expertise in explosives management allows for highly personalised solutions that meet unique client needs to enhance operational efficiency and safety across all operations.