High-Strength Shock Tube (VOD ≥2000 m/s) Supplier South Africa

What Is High-Strength Shock Tube?

High-strength shock tube is the higher-specification grade of shock tube signal line used in non-electric blast initiation systems. Shock tube is a hollow plastic tube with a thin reactive inner coating of HMX or RDX-based explosive mixture at very low loading density (~15 mg/m). When initiated at one end, it propagates a low-energy signal (not a detonation — it does not initiate sympathetic detonation in adjacent tube) at high velocity (≥2,000 m/s for high-strength grade) down the tube. The signal arrives at the detonator connected to the far end and initiates it. High-strength shock tube is used where the trunkline or downline must survive demanding conditions — high pull-through force during stemming of blast holes, rough handling in underground headings, or long signal distances where tube integrity is critical.

Trunkline and Downline Applications

In a non-electric blast circuit, shock tube is used in two roles: as downline (the tube from the detonator in the blast hole up to the hole collar, typically 3–6 m) and as trunkline (the surface signal line connecting from the initiation point along the surface, distributing signal to all blast holes via surface delay connectors or J-hooks). High-strength shock tube is specified for trunkline applications where longer runs, surface traffic, and rough terrain impose mechanical demands on the tube; and for downline applications in deep or hard-to-access blast holes where the tube must withstand pull forces when charged holes are stemmed. The high signal velocity (≥2,000 m/s) ensures signal arrives at all detonators without delay that would upset inter-hole timing.

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Shock tube does not detonate when cut, burned, or knotted — it deflagrates locally and does not propagate. It is classified as a blasting accessory and is significantly less sensitive than detonators or explosive charges. However, as a component of a blast initiation system, it is a controlled product in South Africa and requires appropriate explosives accessories licensing for supply. Terracore Chemicals supplies high-strength shock tube in standard coil lengths (10 m, 25 m, 50 m) and custom cut lengths to licensed mining and blasting operations across Southern Africa.