Silica Dust in Mining

Production drilling into quartz-bearing rock generates concentrated RCS at the drill collar and along blast hole rows. Open-pit blast events disperse silica-laden dust across large areas, exposing blast crews, stemming operators, and downstream workers. Underground long-hole drilling in confined stopes concentrates dust where ventilation is insufficient to dilute below the WES.

Primary, secondary, and tertiary crushers break ore and waste rock, generating sustained RCS emissions from impact and abrasion. Vibrating screens, conveyor transfer points, and surge bins are persistent dust sources. Workers in crusher cabins, on maintenance platforms, and at screen decks face chronic exposure unless enclosed cabins are pressurised and filtered.

Haul trucks travelling on unsealed roads resuspend silica-containing dust from road surfaces. Stockpile loading, reclaiming, and dozer work on ROM pads generate additional RCS. Water suppression and chemical dust suppressants reduce but do not eliminate exposure for operators and nearby workers.

Mechanical development using jumbos and roadheaders produces fine RCS from rock cutting. Shotcrete application generates rebound dust containing crystallite silica and cement alkalinity. Ventilation effectiveness in development headings directly determines the duration and magnitude of RCS exposure for the development crew.

Typical Worker Groups

Common similar exposure groups (SEGs) assessed for this sub-category.

Regulatory Context

Mining-specific WHS legislation applies in each state. In Western Australia, the Mines Safety and Inspection Act 1994 (transitioning to the WHS Mines Act) and the Resources Safety division of DMIRS regulate silica exposure. The WES of 0.05 mg/m³ TWA for RCS applies nationally. From 1 December 2026, this transitions to a Workplace Exposure Limit (WEL). Health surveillance including spirometry and chest imaging is mandatory for workers with significant RCS exposure. DMIRS and state mines inspectorates conduct targeted dust campaigns at crushing plants and underground operations.