shotfiring

Shotfiring is the controlled placement and detonation of explosive charges to fragment and displace rock in mining, quarrying, and tunnelling operations. A shotfirer prepares boreholes, loads them with explosives and detonators, and triggers the blast sequence to break ore bodies or overburden into manageable sizes. The work requires precision timing, exact charge weight calculation, and strict adherence to safety protocols, since poor execution risks flyrock, uncontrolled fragmentation, or personnel injury.

The typical shotfiring cycle involves drilling parallel boreholes into the target rock face, usually spaced 0.5 to 3 metres apart depending on rock type and desired fragment size. The shotfirer inserts explosive cartridges (dynamite, ANFO, or other formulations) and a detonator into each hole, then connects the detonators with detonating cord to create a timed sequence. Modern operations use electronic detonators that fire in precise millisecond intervals, allowing controlled placement of peak blast pressure and directing rock movement toward open space rather than occupied areas.

Rock type, moisture content, and structural features determine charge selection and loading density. Soft sandstone requires lighter charges than hard granite; wet boreholes demand waterproof cartridges or ANFO emulsion. The shotfirer must read the geology on site and adjust hole spacing, burden (distance from borehole to free face), and powder factor (kilograms of explosive per tonne of rock) accordingly. Poor judgement here produces either excessive flyrock and dust, or insufficient fragmentation that increases downstream costs in loading and crushing.

In metal and coal mining, shotfiring is routine in open pit and underground operations. Quarries use shotfiring for aggregate and dimension stone extraction. Tunnelling and civil works employ similar techniques. The role also appears in building demolition, where structural explosives are placed to topple or implode structures, though this work is often called controlled demolition to distinguish it from extraction blasting.

The term shotfirer or shotfiring crew reflects the historical use of black powder and percussion caps, when the charge was literally fired with a burning match or fuse. Modern shotfirers are licensed in most jurisdictions and must hold qualifications in explosives handling, blast design, and risk assessment. Poor shotfiring causes waste (unbroken rock, oversize), safety incidents (flyrock hitting equipment or workers), and environmental damage (ground vibration affecting nearby structures). Competence in reading geology and adjusting to site conditions separates routine work from craft expertise.