Explosive containing TNT instead of nitroglycerin to sensitize ammonium nitrate; a little aluminum powder may also be added to increase power and sensitiveness. Straight TNTammonium nitrate explosives usually contain 15% to 18% TNT and 82% to 85% ammonium nitrate. TNT-ammonium nitrate explosives have densities between 1.0 g/cm₃and 1.2 g/cm₃and velocities of detonation between 3,200 m/s and 4,000 m/s. They are reasonably free from noxious fumes. This type of explosive is susceptible to moisture and should be used only in dry conditions unless packed in sealed containers. The main use of non-nitroglycerin explosives is in primary blasting in quarries and opencast mining, although they are used in some underground work, particularly in ironstone mining. The combination of high strength and relatively high velocity of detonation also makes them applicable for secondary blasting by plaster shooting.