Emulsion explosives consist of microdroplets of super-saturated oxidizer solution within an oil matrix.  In most cases the oxidizer consists of ammonium nitrate.  The oxidizer is dissolved in water which makes up about 9-12% of the emulsion.  Emulsions are generally used in wet blastholes, where ANFO would be ineffective.  Emulsion explosives have better water resistance than both watergel explosives and ANFO.

Emulsion explosives are better in cold weather environments because their sensitivity does not decrease as significantly as watergel explosives.  

Emulsion explosives are relatively insensitive to detonation by friction, impact, or fire.

Standard emulsion explosives are sensitized by air or gas bubbles.  In some cases, the emulsion is made more sensitized by the addition of fuel grade aluminum powder.

For underground mining, emulsion explosives are typically packaged in a thin, tough plastic film, giving it a good degree of rigidity and resistance to rupture during normal handling and tamping.  

Emulsions can also be prepared as bulk explosives for large surface mining operations.  As a bulk explosive the can be blended in varying ratios with ANFO to produce what is known as "Heavy ANFO".  Varying the emulsion content will vary the shock/gas ratio for improved vibration control, increased shock energy for fragmentation, or increased heave for cast blasting. 

Typical properties of emulsion explosives are provided in Table 1.

Table 1:  Typical Properties for Emulsion and Emulsion/ANFO blends