Quality Control (QC) in mining refers to the operational techniques and activities used to monitor, measure, and evaluate the quality of samples, analytical results, and processes throughout mining operations to detect errors, biases, and inconsistencies. In contrast to quality assurance, which is proactive and process-oriented, quality control is reactive and product-oriented — it verifies whether the output meets specified quality criteria. In bauxite mining, QC activities include the regular insertion of blanks, certified reference materials (CRMs), and duplicates into the sample stream to detect cross-contamination, analytical drift, and reproducibility issues. In gold mining, QC is particularly critical during the resource estimation phase, where small errors in gold grade can translate into significant financial consequences. Standard QC practices include monitoring control charts, calculating z-scores for CRM results, and flagging failures for re-analysis. In iron ore operations, QC encompasses the verification of density measurements, chemical assays, and moisture content determinations. For diamond mining, QC extends to the evaluation of stone recovery rates, stone size distributions, and carat accounting at different stages of the process. Effective quality control requires well-trained personnel, clearly documented procedures, calibrated equipment, and a systematic approach to data review. QC data is typically compiled and reported in periodic QC reports that inform decisions about the reliability of datasets used for resource estimation and mine planning.
