Iran 1200t/d Gold Mine Retrofit and Expansion Project

Crushing System Optimization: The expansion reused the original crushing and screening process, with only a new conveyor belt added to connect the fine ore bin to the new line. This maintained the final crushing size at ≤15mm, boosting capacity without major civil works and shortening the overall timeline.  

Upgraded Two-Stage Closed-Circuit Grinding & Classification: The two-stage closed-circuit grinding system was retained, with a primary ball mill and spiral classifier, and a secondary ball mill and cyclone. The grinding fineness was controlled at 80–85% passing 200 mesh. By slightly coarsening the grind, the plant achieved 1500t/d actual throughput without compromising leaching or recovery rates.  

Expanded 10-Stage Cyanide Leaching System: The leaching system was upgraded to ten dual-impeller leaching tanks, operating at 40% pulp density and 26 hours retention time. High-pressure Roots blowers enhanced oxygen supply, ensuring effective and stable cyanide leaching for the expanded plant.  

Integrated Adsorption, Desorption & Electrolysis: Gold-loaded solution was adsorbed by activated carbon, and the loaded carbon was processed in an efficient desorption and electrolysis system. Xinhai’s technology ensured high desorption rates, short cycles, and high-grade gold sludge, making the gold recovery process continuous and efficient.  

Upgraded Tailings Dewatering System: A press filter with squeezing and backwashing functions was installed to improve pregnant solution recovery and reduce filter cake moisture. This facilitated transport and storage, enhanced environmental performance, and ensured stable plant operation at 1500t/d.