Metallurgical Accounting in Mineral Processing

Mass Balancing · Sampling · Recovery · Reconciliation · Plant Performance

Metallurgical accounting is the backbone of every mineral processing operation — the discipline that turns tonnes, grades and assays into numbers a company can bank, a partner can trust and an auditor can sign. Yet most practitioners learn it piecemeal: a recovery formula here, a moisture correction there, and years of inherited spreadsheets that don’t always agree.

This book sets out the complete system.

Drawing on the internationally recognised AMIRA P754 Code of Practice, Tony Escorcio presents a full, defensible framework for metal accounting — from measurement and sampling to reconciliation, reporting and assurance. Every concept is demonstrated through a single running case study: a Witwatersrand gold plant treating 476.2 t/h and producing ~29 600 oz/month, allowing readers to see each technique on a common footing.

What You Will Learn

• Why metallurgical accounting matters and how it underpins revenue, inventory, reconciliation and auditability.
• The AMIRA P754 principles and how to build a compliant, defensible accounting system.
• Sampling theory and practice, including Gy’s FSE model, heterogeneity, nugget effect, correct cutters, and QA/QC (CRMs, blanks, duplicates, umpire assays).
• Measurement systems: belt weighers, flow meters, density gauges, moisture, slurry calculations and error propagation.
• Recovery calculations for two‑product, multi‑product and complex circuits.
• Weighted least‑squares data reconciliation, with closed‑form spreadsheet solutions and gross‑error detection.
• Circuit accounting for flotation, gravity, CIL/CIP, elution and gold-room operations.
• In‑circuit inventory, lock‑up and the call factor, including carbon inventory and gravity lock‑up.
• Stockpile, concentrate and tailings accounting, including survey-based valuation.
• Mine–plant–sales reconciliation, Mine Call Factor, payable metal, TC/RC, penalties and settlement.
• A complete month-end balance, fully reconciled and signed off.

Who This Book Is For

• Plant metallurgists and processing engineers
• Metallurgical accountants and production controllers
• Graduate engineers entering site work
• Auditors, partners and technical managers needing assurance over production figures
• Anyone responsible for reporting tonnes, grades, recoveries or metal balances