QA/QC in mining stands for Quality Assurance and Quality Control, a systematic framework ensuring data reliability, particularly in sampling, assays, and geological modeling. QA focuses on proactive prevention of errors through planning and protocols, while QC involves reactive checks like blanks, duplicates, and standards to detect issues such as contamination or bias.
In mining exploration, QA/QC monitors precision and accuracy of geochemical data from drill core, soil, or rock samples, using tools like certified reference materials and field duplicates. These practices comply with standards like NI 43-101, validating databases for resource estimation and investment decisions [1].
Effective QA/QC reduces financial risks from flawed data, improves lab performance oversight, and supports regulatory reporting, typically adding 1-2% to exploration costs but preventing multimillion-dollar errors. Continuous monitoring during drilling programs allows real-time corrections [2].
Geologists ensure QA/QC in sampling by implementing systematic protocols to minimize errors, contamination, and bias throughout the process. These practices draw from established frameworks like the Theory of Sampling (TOS) and industry standards from organizations such as AusIMM and SRK Consulting.
Core QA principles
Quality assurance starts with detailed planning to quantify potential errors at each sampling stage, from collection to assaying. Protocols should define sample volumes, layouts, and error limits tailored to the deposit type, ground conditions, and mineralization style.
Field personnel must document observations rigorously, including lithology, sample intervals, and site conditions, using checklists to catch up to 70% of errors that occur in the field [3].
QC sample insertion
Insert QA/QC samples like blanks, certified standards, and duplicates at regular intervals, ideally comprising 10% of the batch, to monitor contamination, accuracy, and precision [4].
For drill core or soil sampling, split samples consistently using clean, non-metallic tools and riffle splitters after drying to preserve representativeness [5].
Best field practices
Standardize depths and avoid disturbed areas to reduce variability; label samples uniquely with GPS data and maintain cleanliness to prevent cross-contamination.
Train staff on procedures and conduct timely QC reporting against predefined benchmarks for ongoing improvement.
Reference
[1] A. S. and G. Gosson, “Quality control reporting requirements by the mining industry.” Accessed: Jan. 08, 2026. [Online]. Available: https://mrmr.cim.org/en/library/magazine-articles/quality-control-reporting-requirements-by-the-mining-industry/
[2] C. Case, “QAQC applied to the mining industry,” Core Case. Accessed: Jan. 08, 2026. [Online]. Available: https://corecase.com/en/qaqc-applied-to-the-mining-industry/
[3] B. W. Smee, L. Bloom, D. Arne, and D. Heberlein, “Practical applications of quality assurance and quality control in mineral exploration, resource estimation and mining programmes: a review of recommended international practices,” Geochemistry: Exploration, Environment, Analysis, vol. 24, no. 2, pp. geochem2023-046, Apr. 2024, doi: 10.1144/geochem2023-046.
[4] L. K. I. Consulting, “Geochemical Sample Preparation: A Focus on Drill Core Samples,” LKI Consulting. Accessed: Jan. 08, 2026. [Online]. Available: https://lkiconsulting.com/2025/01/geochemical-sample-preparation-a-focus-on-drill-core-samples/
[5] B. Goss, “Soil Sampling Techniques in Mineral Exploration | Rangefront,” Rangefront Mining Services. Accessed: Jan. 08, 2026. [Online]. Available: https://rangefront.com/blog/soil-sampling-techniques/
