53 Redefining real-world exposure: advanced mineralogical characterisation of respirable particles from mining and engineered stone

Abstract Accurately assessing what workers inhale has long been constrained by the oversimplification inherent in gravimetric, bulk, and laboratory-generated aerosol methods that focus narrowly on particle size and shape or bulk composition. Real-world exposures are far more complex, representing dynamic mixtures of minerals, metals, and fibres that vary with geology, process, and control conditions. This study presents a step-change in exposure assessment through an advanced mineralogical characterisation workflow, developed and applied across mining, smelting, and engineered stone environments on three continents. Using the Mineral Liberation Analyser (MLA) with automated SEM-EDS mapping, individual particles were classified by size, shape and chemistry, enabling quantitative linkage between particle size distribution, morphology and mineralogy. Across the dataset, 42 distinct mineralogies were identified within the respirable fraction, including silicates, oxides, sulphides and multi-phase metal compounds. Silica particles showed striking differences in size between industries, with engineered stone dominated by fine and ultrafine particles compared to coarser crystalline forms in mining dusts. These differences are of increasing significance as Australia becomes the first country in the world to ban high-silica engineered stone. This multi-award-winning methodology reveals that occupational dusts are not uniform hazards but complex, reactive systems. Particle size, shape and surface chemistry jointly determine deposition, persistence and biological interaction. Recognising this complexity transforms how we interpret exposure, evaluate toxicology and design controls. By bridging mineralogical science and occupational health, this work establishes a new benchmark for understanding and preventing particle-induced disease.