Project Overview
Location: Pará State, Brazil
Process Type: Heap Leach with ADR Plant
Annual Production: 720,000 tonnes (1,973 tpd)
Feed Grade: 0.81 g/t Au
Recovery Rate: 86.9% (average)
Final Product: 16,292 ounces gold per year
Project Stage: Pre-feasibility Study
Detailed Process Description
Primary Processing
The Cuiú Cuiú Project employs an innovative heap leach processing circuit utilizing an on/off pad design. The processing facility begins with primary crushing, followed by an agglomeration phase where cement is added at a rate of 10 to 15 kg per tonne of material. This agglomeration step is crucial as the ore, while predominantly fine, presents in large clumps that require proper binding for optimal leaching performance.
Heap Leach Configuration
The facility features four dedicated on/off heap leach pads, with operations designed to have two pads under active leaching while the other two undergo loading and unloading cycles. Each pad is limited to a single 5-meter-high lift to minimize compaction risks and maintain optimal solution flow. The leaching cycle extends for 60 days, followed by a 12-day rinsing and neutralization period, and an 18-day window for leached ore removal.
Recovery Process
Gold recovery utilizes a carbon-in-column (CIC) circuit consisting of six contactors arranged in cascade operation. The pregnant solution flows through the circuit at a nominal rate of 210 m³/h. The design solution-to-ore ratio is maintained at 2.4:1 to achieve target gold recovery rates. The process demonstrates varying recovery efficiencies across different ore types: MG Blanket (88.0%), MG saprolite (90.5%), Central Blanket (91.0%), and Central saprolite (72.5%).
Production Capacity
Over the project’s 5-year life, the facility is designed to process approximately 3.23 Mt of ore with an average grade of 0.81 g/t Au, yielding a total of 72.84 koz Au. The crushing circuit operates at a nominal rate of 720,000 tonnes per annum, equivalent to 1,973 tonnes per day, with the ROM processing design rate set at 2,367 tonnes per day, including a 20% design factor.
Environmental Controls
The facility incorporates comprehensive environmental controls, including solution management systems and proper containment measures. The process includes detailed protocols for cyanide management and solution recycling, ensuring environmental compliance while maintaining optimal gold recovery rates.
