TESTING SAMPLE REPRESENTIVITY USING PARTICLE SIZE DISTRIBUTION
DOI:
https://doi.org/10.17159/Abstract
Particle size distribution (PSD) analysis is important to many industries for assessing product quality, process efficiency, and compliance with contractual standards, while ensuring sample accuracy and representativeness. Inaccurate PSD results, arising from fines as a result of excessive handling can lead to penalties and buyer-seller disputes. A non-representative PSD means samples will not be representative of the chemical components either. Sampling blast-hole cuttings poses challenges due to large material volumes, segregation, and uneven settling of particles in dense gold bearing ores. Commonly used sampling methods such as spear or sectoral sampling may lack representativeness. PSD analysis is crucial for evaluating sampling methods by comparing test sample representativeness against a reference standard derived from multiple PSD analyses. Acceptable samples must fall within the 97.5% confidence intervals of the standard; deviations. Analyses lying outside these boundaries indicate a strong likelihood of segregation errors. A case study demonstrates this approach by using a 6.005 kg benchmark sample to assess two additional samples (1 kg and 5 kg), highlighting PSD’s role in detecting sampling errors and refining protocols. An example of three test samples collected from RC drill cuttings compared to a standard reference sample is presented to illustrate a QAQC procedure for RC drilling.
Key words: particle size distribution, mass fraction, sample representivity, relative difference, RC drilling
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Copyright (c) 2026 Richard Charles Anson Minnitt; Prof Minkkinen
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