Executive Summary

The global gold mining sector is increasingly turning to tailings retreatment—the reprocessing of historical waste—to secure low-risk, immediate production. While standard retreatment projects often target grades as low as 0.3 g/t, a resource grading 3.0 g/t Au represents a significant value anomaly.

Such a high grade in a tailings dam typically signals historical processing failures, often linked to refractory mineralogy (sulfide encapsulation) or preg-robbing characteristics.

This report evaluates two primary metallurgical flowsheets for monetizing this high-grade resource:

Route A: Direct Carbon-in-Pulp (CIP)

Route B: Flotation Concentration + Ultra-Fine Grinding (UFG) + Intensive Leaching

Our analysis indicates that for a 3.0 g/t resource, the Flotation + Concentrate Leach route is generally the superior investment choice. Direct CIP requires the construction of massive tank farms to leach 100% of the tailings volume before adsorption can occur.

If the ore contains natural carbon (common in historical tailings), dissolved gold will be adsorbed by this natural carbon during the leach phase and lost to the tails before it ever reaches the activated carbon recovery circuit (the “preg-robbing” effect).

Financially, Direct CIP is capital-intensive due to the requirement for separate, large-scale leaching and adsorption trains. It also exposes the operator to linear scaling costs for reagents (cyanide and lime) across the entire tonnage.

The Flotation route creates a “split stream” outcome, significantly reducing the volume of material requiring high-cost comminution and detoxification, thereby improving the project’s long-term environmental liability profile and Net Present Value (NPV).