Segregation Testing of Category 2 Explosive Transport Boxes

When transporting incompatible mixed loads of explosives, typically Division 1.1B detonators (initiation explosives, IE) with Division 1.1D high explosives (HE), the requirements of Section 7.3.2 of the Australian Code for the Transport of Explosives by Road and Rail, Third Edition^{ý 1} (AEC3) must be met. This requires adequate separation between incompatible explosives, and if not possible, the vehicle must be fitted with an effective means of segregation demonstrated to prevent sympathetic detonation of incompatible explosives (i.e., segregation barrier approved by the Competent Authority).

A series of practical tests were proposed to evaluate the effectiveness of typical explosive segregation, to act as evidence to demonstrate the effectiveness of the Category 2 carry box segregation typically in use in the Australian coal mining industry.

The test schedule proposed to:

• Evaluate two common manufacturers of Category 2 carry boxes, the maximum theoretical load of detonators and the smallest reasonable segregation distance observed between carry boxes in industry;
• Acquire carry boxes and trayback analogue;
• Install the carry boxes on the trayback with a representative separation distance, fill one box with a maximum load of detonators and initiate; and
• Measure the effect on the adjacent high explosive carry box.

On initiation of both tests, the destruction of the IE box was violent and rapid. The damage was observed to occur primarily from gas pressure, which acted to deform and bow the IE box panels outwards before the tensile stress became sufficient to remove the door and tear the welds that join each panel. The IE box was pushed against the HE box from the force of the explosion. Both tests showed no internal damage to the HE box, except for minor denting on the outside of the HE box and minor cracking of the internal plywood lining. The detonation was observed to cause the HE door to open. There was no sympathetic detonation of the HE contained in the HE box.

These results show the two manufacturers' Category 2 carry boxes, tested with a minimum 345mm separation distance between the IE box and the HE box, met the segregation barrier requirements of Section 7.3.2 of AEC3. The scope of this report is the transport of non-electric and electronic detonators and does not extend to electric and plain detonators.