In 2022, Zaldivar began the implementation of the chloride leaching project, which modified the way it operates its hydrometallurgical plant, moving from leaching oxide ores with acid and humidity of 3% to leaching mixed sulphide ores with sodium chloride (brine), sulphuric acid and humidity of around 8%. In addition, during this commissioning period, the percentage of fine ore input to the plant increased from 10% to 18%, being its limit of 15%, which generates problems of excessive adherence of material in essential equipments of the stacking system (ore transport system to leaching and stacker bridge) with their respective structures, equipment and components, which include: belts, scrapers, guide plates, idlers and rollers, Senet Tripper, buildings, tensioning systems, electrical panels, boards, sensors, wiring and hydraulic components, etc. This condition, together with the presence of acid vapours, is causing accelerated wear, corrosion, degradation of materials, difficulty in inspections, increased maintenance times, increased weight of structures and increased difficulty, time and frequency of cleaning (approximately every 3 days), for which the equipment must be shut down.

Identify solutions or technological developments to:

• Avoid, reduce and/or eliminate the adherence and accumulation of fine and wet material in structures, equipment and components of the ore transport systems to leaching and the stacker bridge, without generating any risk to people.
• Mitigate the effect of acid vapours (HCl) which affect electrical transmission lines and electrical or electronic components.

• Solution or technology development must be compatible with operation above 3000 m.a.s.l. (meters above sea level).
• For technological solutions involving chemicals, these must not cause adverse effects on downstream leaching, SX and EW processes.
• Minimal worker requirements for implementation and application.
• Minimal operational interference for installation, operation and maintenance of the proposed solution.
• Meet Zaldivar Mine’s health, safety and environmental standards.

Not relevant

The following will not be considered in the evaluation process:

• Consultancies or diagnostic studies.
• Solutions involving changes in mine planning.
• Solutions that involve changes in the current hydrometallurgical process conditions.

• Reduce the accumulation of material on the structures of the ore transport system and stacker bridge.
• Decrease risk exposure of cleaning, operations and maintenance personnel.
• Increased availability of the ore conveying system and stacker bridge.
• Operational continuity.
• Increased plant productivity.

Cleaning times (hours) Availability of stacker bridge Frequency of cleaning Mean time to recovery/maintenance (MTTR) Stacking performance (ktpd – ktonne per day)

Area of interest: Leaching

Interested management: Copper Recovery Project