Explosive Booster (for Insensitive Explosives) Supplier South Africa

What Is an Explosive Booster?

An explosive booster (primer) is a small cast or pressed high-explosive charge used to reliably initiate a column of bulk explosive that is insufficiently sensitive to be initiated directly by a commercial detonator alone. Modern bulk emulsion explosives and heavy ANFO (emulsion/ANFO blends) are formulated to be relatively insensitive for safety in transport, handling, and storage — this means that the output of a standard commercial detonator (typically ~1–2 g PETN equivalent) may not reliably initiate a large column of dense emulsion. The booster bridges this sensitivity gap: the detonator reliably initiates the booster (which is more sensitive than the bulk explosive), and the booster’s higher-energy output — from 150 g to 1 kg of PETN, RDX, or Pentolite — provides sufficient impulse to reliably initiate the emulsion or heavy ANFO column in all practical conditions.

Booster Selection and Placement

Booster size (weight) is selected based on the column explosive’s critical diameter and sensitivity, the blast hole diameter, and the length of the explosive column requiring initiation. For standard emulsion explosives in blast holes of 75–200 mm diameter, a 400–500 g PETN booster is typically used. For larger-diameter holes (200–380 mm) with dense emulsion at the bottom, a 1 kg booster may be specified. The booster is placed at the toe (bottom) of the explosive column — where reliable initiation is most critical — with the detonator inserted into the central detonator well and the shock tube or lead wires routed up through the explosive column. In some blast designs, a second booster is placed mid-column (for very deep holes) to ensure complete detonation.

Supply and Regulatory Requirements

Explosive boosters contain high explosive (PETN, RDX, or Pentolite) and are classified as Schedule 1 explosives under the Explosives Act (South Africa). Supply is restricted to licensed mining and blasting operations with valid explosives licences. Boosters must be stored in a licensed explosives magazine separately from detonators. Terracore Chemicals supplies cast PETN and Pentolite boosters in standard sizes (150 g, 400 g, 500 g, 1 kg) to licensed mining operations across Southern Africa. Enquiries require explosives licence reference and delivery site details.