An Emulsion Explosive is a type of high-performance bulk commercial explosive that is extensively used in surface and underground blasting operations across all major mining sectors, including bauxite, gold, iron ore, and diamond mining. It is manufactured by emulsifying a supersaturated solution of ammonium nitrate (and sometimes other oxidizer salts) in a hydrocarbon-based continuous phase — such as mineral oil or fuel oil — using an emulsifier to create a stable water-in-oil emulsion. The resulting product is a white, viscous, paste-like material that is chemically oxygen-balanced, water-resistant, and highly detonable when sensitized. Sensitization is typically achieved by incorporating glass microspheres, chemical gassing agents, or expanded polystyrene beads that create microscopic voids within the emulsion matrix, which act as hot spots upon initiation and sustain detonation.
Emulsion explosives offer significant advantages over older explosive technologies such as ANFO (ammonium nitrate fuel oil) in wet and water-logged blastholes — a common challenge in tropical bauxite deposits and deep gold mining environments — due to their inherent water resistance. Their energy output, velocity of detonation (VOD), and brisance (shattering force) can be precisely controlled by varying the sensitizer concentration and gassing level, making them highly versatile across a wide range of rock conditions. In iron ore and diamond mining, emulsion explosives are formulated to optimize fragmentation while minimizing fly rock, ground vibration, and airblast, which are critical environmental and safety considerations. Emulsion explosives are typically manufactured and pumped directly into blastholes using Mobile Manufacturing Units (MMUs) — purpose-built vehicles equipped with bulk storage tanks, mixing systems, and pumping equipment — ensuring freshness, consistency, and safety. Strict regulatory controls govern the manufacture, transport, storage, handling, and detonation of emulsion explosives at all mine sites.