Polar SX Emulsion Case Study

Polar SX emulsion

NSA manufactures a robust, low water content, emulsion, that provides higher energy than other offerings in the market. The Polar SX series of products can be delivered at densities of 0.85gcm-3 to 1.25 gcm-3, enabling the product to be matched to all types of rock mass.

Polar SX 70% ANE / 30% ANFO Blend

The challenge

Ammonium Nitrate Emulsion (ANE) is manufactured by melting high purity ammonium nitrate and emulsifying it with a fuel. By keeping the water used in melting the AN as low as possible, a more energetic ANE is produced when compared to those with higher water volumes.

Increased water content will result in a lower energy product – water is an energy sink.   These emulsions, in medium to soft ground conditions, undergo sub optimal detonation, resulting in lower energy output and a potentially higher fume output.

Table 1 displays the effects of water content on the energy rating of the ANE solution.

Emulsion based bulk explosives are typically loaded into the hole with densities from 1.15 gcm-3 to 1.25 gcm-3,  based on the convention that the higher the powder factor  the better the blast result. As the powder factor does not define the contained energy (Mj/Kg), (it defines the explosive mass at an unknown energy rating), it cannot be used as an indicator to select explosives density.

In a similar manner, it is believed that ANE bulk explosives final density must be denser than water (1.0 gcm-3 to 1.05 gcm-3) to ensure that it does not float. This is not the case. Bulk ANE explosives are pumped into blast holes at densities greater than 1.2 gcm-3, i.e. denser than water. By using the correct loading techniques, bulk ANE explosive, loaded into the hole from the bottom of the blast hole in a continuous column, displaces the water by forcing the water towards the collar of the blast hole. Once the column of bulk explosives starts to gas (expand and sensitise), the water is pushed further up by the explosive.

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