Caserones Mining Company’s concentrator plant currently processes more than 4,000 tons per hour of sulfide ore with an average grade of 0.45% of total copper to produce over 110,000 tons of fine copper per year. The ore that feeds this plant currently has considerable variability in its mineralogy, with a greater presence of chalcocite than chalcopyrite. This has meant an increase in the acidity of the ore (natural pH less than 5), which generates an increase in lime consumption when controlling the pH in the collective flotation (Rougher pH 9 and Cleaner pH 11). The historical rate of lime consumption is 1.2 kg/t of ore, however, currently they have reached occasional consumptions greater than 2 kg/t, which is affecting the level of ore treatment due to the current capacity of the lime slurry preparation plant.

Technological solutions are sought to reduce lime consumption in the flotation process by operating at a higher level of treatment of ores with a low natural pH. Solutions are expected in the areas of chemical reagents, operation at lower pH, process control and optimization, among others.

• No adverse effects on metallurgical parameters such as copper recovery, concentrate grade, impurity content or others.
• It must consider a preliminary protocol for tests at different levels (concept, pilot plant and industrial).
• It must be able for the execution of tests, implementation and/or evaluation in industrial plant, with a high degree of reversibility (recover initial condition if necessary).
• For chemical products, it must provide fundamentals of the mechanism of action, technical data sheet and safety data sheet.
• A high level of automation is desirable, so it should consider minimal or no human intervention during testing or implementation.
• It must be compatible with the infrastructure available at Caserones and must not generate operational interferences for its installation, operation and maintenance
• The solution must be compatible with adverse environmental and climatic conditions such as low temperatures, wind, fog, rain, snow, humidity, particulate material, among others.
• Comply with Caserones safety, personal health and environmental standards.

The ore feeding the concentrator plant has experienced an increase in acidity which has generated an increase in lime consumption when operating at the standard pH, which maximizes copper recovery and concentrate quality

• Risk of losses in mineral processing due to restrictions in the lime slurry plant’s pre-treating capacity.
• Increased costs due to higher lime consumption.

Permanently.

• Lime dosage based on pH adjustment in pre-flotation conditioning stage.
• Maximum lime dosage of 1.8 kg/t ore per slurry plant restriction.

New technologies have not been successfully tested.

The following will not be considered in the background evaluation process:

• Solutions that significantly modify the plant infrastructure.
• Solutions that generate changes in the process flowsheet or affect operational continuity.
• Advisories, consultancies or engineering studies.