Shock Tube Initiation Systems
A shock tube is a non-electric detonator in the form of a small diameter hollow plastic tube. This tube shocks the explosive through the use of a percussive wave traveling down the length of the tube. It usually contains a small amount of Octahydro-1,3,5,7Tetranitro-1,3,5,7-Tetrazocine (HMX)/aluminum explosive powder on the tube’s inner diameter, which detonates at great speed. These systems take a precise energy input to initiate the reaction inside the tube. It may be initiated by detonating cord, EB cap, cap and fuse, or a starter consisting of a shotgun primer in a firing device. The unique aspects of shock tube systems are:
- They are safe from some electrical hazards and radio frequency hazards.
- They are noiseless on the surface.
- They will not initiate cap sensitive explosives in the blastholes.
- They will propagate a reaction through and around tight kinks and knots.
Long Period Shock Tube Initiators provide precise non-electric delay initiation for all underground mining, shaft sinking, and special construction needs. The delay caps are available in different lengths of the shock tube. Shock tube detonators are suited for use with commercially available dynamites, cap sensitive water gels, or emulsion type high explosives because the tube will not initiate or disrupt these explosives. Shock tube initiators can be used for initiation of non-cap sensitive blasting agents with a suitable primer.
Long length, heavy duty (LLHD) millisecond initiators are similar to the Long Period (LP) initiators except that their delays are of shorter intervals. The LLHD unit has a long length tube that extends to the collar of the blasthole. The long length tube eliminates the need for any detonating cord in the blasthole that allows the use of cap sensitive explosives in the hole. Trunkline delays are usually used in place of detonating cord trunklines. All units contain built-in delays to replace conventional millisecond connectors used with detonating cord. Trunkline delays are factory assembled units with five main components, the shock tube, the blasting cap, the connector, the delay tag, and the plastic sleeve.