Shock (or signal) tubing is the basis of all non-electric initiation systems. Shock tubing consists of a 3 mm outer diameter plastic tube with a 1 mm hollow core. The core is lined with a coating of reactive powder (HMX and Aluminium) at around 16 grams per kilometre.

Shock tube can be reliably initiated by detonators or detonating cord but is succeptible to failure from shrapnel damage.

Fired shock tube above - note core is slightly blackened

Unfired shock tube above - note aluminium appears as a silvery coating

Shock tube is a robust and reliable product however liquid penetration of the core will cause failure. The common modes are:

• Oil penetration due to excessive sleep times in bulk explosives
• Water ingress through damaged sections. Damage is primarily caused by shrapnel from detonators, detonating cord or rock fragments projected across the blast.

ShockStar or Shock*Star detonators are non-electric detonators supplied by the Austin Powder Company.

The ShockStar range covers both surface and in-hole delays.

A shockstar surface delay detonator can accept a maximum of 8 shock tubes

A shockstar bunch connector using a detonating cord loop can accept a maximum of 20 shock tubes

And comes in a range of colours and delays

Shorted and Sheathed refers to the leg wires of electric detonators as supplied from the factory.

Shorting prevent stray currents from creating a voltage across the bridge wire that could lead to accidental initiaiton. Shorting is achieved by twisting the leg wires together.

Sheathing prevent the exposed ends of the leg wires from accidental contact with electrical sources. Sheathing is achieved by placing a non-conductive plastic tube over the exposed ends of the leg wires.

In Australia all electric detonators must be supplied shorted and sheathed.

Shorted and sheated electric detonators.

The shot pack is the general name given to the document set provided to the shotfirer to complete a blast. The shot pack will generally include the following:

• Drill plan with design depths and dip sheets for measuring the hole depth and water.
• Backfill sheets showing over depth hoes and the amount of backfill required.
• Charge sheets showing the amount and type of explosives required in each hole.
• Tie Up Plan showing the initiaiotn design and sequence as well as the amount of product required.
• Blast clearance plan showing the positions of the blast guards and the blast clearance zone
• Risk assessments for the particular blasts
• Geotechnical issues and warnings.
• Handover notes from previous crews.

The shotfirer log book is the shotfirers personal record of blasting activity. As a minimum it should contain the shot ID, the dates and the activity carried out (prep, loading, firing, recovery)

Required by most regulators, a shotfirer refresher is a training course that builds on an existing Statement of Attainment and enables the trainee to remain ‘current’. A refresher course will not qualify a person for units of competency that are not specifically stated in the original Statement of Attainment. Successful trainees receive a new Statement of Attainment for the current competencies.

All shotfirer course providers must be a registered training organisation (RTO) accredited to deliver the national units of competency for blasting (RIIBLA) as set out in the table below. Further information on the units of competencies is available from Skills DMC at www.skillsdmc.com.au

The current Units of Competency for Shotfirers:

Superseded units of competency from the old MNMG, MNQ and MNC training packages are also valid.

The primary units from the superseded training packages:

A small bore, flexible plastic tube coated internally with an explosive powder that is capable of transmitting a shock wave and explosive spit along the length of the tube. Also commonly known as Shock Tube.

A design standard or site data sheet contains the standard blast design parameters for a specific area, geometry and geological domain on site.

A site standard would be expected to contain the following information.

• Target powder factor
• Design parameters for average conditions (burden, spacing, stemming etc,)
• Application - what geometry / geology is applicable to the standard
• Blast objectives delivered (fragmentation, movement, wall control etc.)

The time between explosives being loaded into a blast hole and their initiation.