Explosive Trains, Blasting Accessories, and Shaped Charges

Explosive Ingredients: All explosives consist of a fuel (e.g., Aluminium, magnesium, charcoal) and an oxidiser (e.g., Ammonium nitrate, potassium chlorate) that react to form detonation gases.
High Explosives: Characterized by detonation velocities greater than approximately $1,000\,m/s$ ; designed to shatter and destroy material.
Low Explosives: Characterized by deflagration velocities less than approximately $1,000\,m/s$ ; primarily used as propellants.
High Explosive Classes: * Primary: Extremely sensitive to heat, shock, or friction; used to initiate other explosives (e.g., Blasting Cap). * Secondary: Relatively insensitive (e.g., Dynamite, $C-4$ ). * Blasting Agent: Low sensitivity products that require a booster; not cap sensitive (e.g., $ANFO$ ).

Explosive Train: A series of components arranged in decreasing sensitivity to achieve effective detonation. High explosive trains generally follow the sequence: Primary $\rightarrow$ Secondary $\rightarrow$ Blasting Agent.
Low Explosive Characteristics: * Support particle-to-particle burning (deflagration) rather than a detonation wave. * Typically require confinement for explosion. * Initiated by flame, spark, heat, or friction (e.g., Black powder, smokeless powder).
Low Explosive Trains: Usually two-step processes, such as the percussion primer and propellant charge in small arms ammunition.

Safety Fuse: A time delay device with a black powder core; burns at approximately $35-45\,sec/ft$ . It has a velocity of combustion ( $VoC$ ) of $120-140\,m/s$ .
Detonating Cord: Also known as det cord or prima cord; contains a white high-explosive core (usually $PETN$ or $RDX$ ). It has a velocity of detonation ( $VoD$ ) between $5500-7000\,m/s$ , allowing for synchronization of multiple charges.
Detonator (Blasting Cap): Small metal cylinders containing primary explosives to initiate charges via shock waves. * Internal Charges: Base charge ( $PETN$ , $RDX$ ), Intermediate charge ( $TNT$ , $HMX$ , $Tetyrl$ ), and Ignition charge (Lead Azide, Lead Styphnate, Mercury Fulminate). * Types: Non-Electric (mechanical, initiated by flame) and Electrical (initiated by electric spark, often featuring a short-circuiting shunt for safety).

Boosters: Devices used to initiate less sensitive blasting agents. * Cast Booster: Common solid mixtures, often $TNT$ with $PETN$ , $RDX$ , or $Tetyrl$ , with a $VoD$ of $20,000$ to over $24,000\,ft/sec$ . * Pentolite Booster: A mixture of $50\%$ $PETN$ and $50\%$ $TNT$ . * Slip-On Booster (SOB): Waterproof units used to enhance the output of a detonator.
Shaped Charges: Utilize directional force ( $90^\circ$ angle to the surface) to create a high-velocity "jet" for cutting or piercing. * Efficiency: Requires a "standoff distance," typically $1/2$ times the cone diameter. * Conical Shaped Charge: Used for punching holes or oil well perforation. * Linear Shaped Charge (LSC): Inverted "V" shape used for uniform linear cutting of steel or concrete; often uses malleable metal liners like copper or aluminium.