Ground broken beyond the design line of blast holes most recently detonated.

Overbreak on the right wall of a large underground excavation.

Backfill sheets are provided to charging operations to enable over length holes to be brough back into tolerance with the design charge depth.

A complete backfill sheet contains the following information:

Ballistic Discs provide a safe and effective way of remotely clearing hang ups and upstanding rill in draw points and stopes. When detonated a ballistic disc produces a large steel slug that is propelled at hypersonic velocity (2000-2600 m/s). The kinetic energy transferred on impact, up to 60 MegaJoules with the BD514, shatters the target area. As accurate aiming is paramount, provision for
a laser aiming attachment is fitted to all disc faces.
Ballistic Disc use in underground mining enables a true "non-stope entry" method of safely removing hang ups. Accordingly Ballistic Disc use is mandatory in several Australian underground mines. Ballistic Discs further aid safe underground operations as they permit the abortion of firing at any stage, and safe recovery of an aborted or misfired round.

Insulated wires (usually of a lighter gauge than the firing cables) used between the detonator lead wires and the firing cables or for lengthening the lead wire of an electric detonator.

A bi-directional booster is crimped onto detonating cord to increase the donor output of the cord.

The booster contains about 2 grams of either HMX or HNS explosives.

The area around a blast that must be evacuated of personnel and equipment during the firing of a blast.

The clearance zone is identified on the firing plan which will also show blast guard positions and other information relevant to the firing.

A person who may be appointed to handle the logistics of the clearance of the Blast Exclusion Zone including (but not limited to) the following:-

• Removal / relocation and preparation of equipment currently within the Blast Exclusion Zone;
• Confirming the position and location of the Blast guards;
• Completing the clearance sweeps of the Blast Exclusion.

Zone once the guards are in place and the area secured.

A blast guard is a person responsible for ensuring the blast clearance zone is evacuated prior to the firing of a blast.

The attached document provides detailed information on the practice of blast guarding.

A mat made of rope, rubber strips, polyethylene tube or similar material, placed over the area or materials being blasted to prevent the scattering of blast-generated debris.