Modern explosives can be classified into two main categories: Blasting Agents (detonator insensitive explosives) High Explosives (detonator sensitive explosives)
Blasting Agents A blasting agent is defined as a chemical mixture which: contains no ingredient that is itself an explosive;, and cannot be initiated by a No.8 detonator in open air.
High Explosives High explosives include watergel explosives, emulsion explosive, dynamite, and cast pentolite boosters. All of these can be reliably detonated with a No. 8 strength detonator or a strand of 10 g/m detonating cord. The key properties of importance in selecting an explosive in addition to price are: water resistance, strength, density, sensitivity, velocity of detonation, fumes, storage and handling requirements, physical characteristics, and flammability. Water Resistance: The water resistance of blasting agents and high explosives is quite variable but all explosives deteriorate progressively with exposure to water. With prolonged exposure and water penetration, there will reach a point at which the detonation wave is unable to propagate through the explosive column Explosive Strength: | 
