Seawater Sulfide Flotation for Copper-Gold Recovery at Domeyko

Source: Tintina Mines Limited (2026)
Website: https://tintinamines.com/

Critical Data

Overview

Tintina Mines Limited is advancing the Domeyko project in Chile’s Atacama Region, a copper-gold sulfide deposit that will utilize a state-of-the-art concentrator plant with a nominal capacity of 35,000 tpd. The facility, evaluated in a Preliminary Economic Assessment (PEA) by SRK Consulting, adopts seawater as the primary process water due to regional water scarcity and the plant’s proximity to the coast. This innovative approach leverages proven technology already in use at major Chilean operations like Esperanza and Sierra Gorda. The concentrator will process an average head grade of 0.35% Cu and 0.25 g/t Au, with higher grades of 0.40% Cu and 0.31 g/t Au expected during the first five years. The recovery methods center on a sulfide flotation circuit integrated with a SAG mill–ball mill grinding stage (SABC-A configuration), pebble crushing, and a regrind circuit. The plant targets a grind size of 150 µm and achieves overall recoveries of 88.21% for total copper and 64.61% for gold over the life of mine. High-density tailings thickening (65% solids) was selected over conventional disposal to reduce seawater consumption and improve sustainability. The project’s significance lies in its adaptation to arid conditions, use of untreated seawater, and incorporation of Jameson pneumatic cells for cleaner flotation to maintain concentrate grades above 26.5% Cu despite challenging pyrite and phyllosilicate chemistry.

Key Process Stages

• Stage 1: Primary Crushing – Run-of-mine ore with controlled particle size is fed into a 42”x55” gyratory crusher (450 kW) at 2,083 tph. The crusher product passes at 80% minus 4 inches and is conveyed to a 35,000-ton covered stockpile, providing a 24-hour buffer. The crushing area operates at 70% utilization (16.6 hours/day) and achieves a product P80 of 4 inches for efficient downstream grinding.
• Stage 2: SAG & Ball Mill Grinding (SABC-A Circuit) – Ore from the stockpile enters a 36 ft x 19 ft SAG mill (12,500 kW) in closed circuit with a pebble crusher and a ball mill (26 ft x 44 ft, 16,000 kW). The SAG mill operates at 7.25 kWh/t, producing a pebble fraction of 21%. The ball mill receives feed with an F80 of 2500–3500 µm and reduces the particle size to a target P80 of 150 µm. Two clusters of 10 hydrocyclones (26”) achieve a circulating load of 300%. Grinding utilization is 92%, equivalent to 22.08 hours per day.
• Stage 3: Rougher Flotation & Regrinding – Flotation begins with six 300 m³ tank cells in series, providing 30 minutes of residence time (scaled from 15-minute lab tests). The rougher stage recovers 92% of copper from a feed slurry at 32% solids, using seawater. The rougher concentrate (9% mass yield) is reground in a Vertimill VTM-3000 (2,000 kW) to a P80 of 45 µm, with energy consumption of 4.84 kWh/t. Regrinding hydrocyclones classify the slurry before cleaning.
• Stage 4: Cleaner Flotation with Jameson Cells – The reground product enters two stages of Jameson pneumatic cells (Mod. B6500/24 and B4000/24) for primary and secondary cleaning. These cells are chosen for their efficiency in fine particle processing and ability to handle the high-pyrite, phyllosilicate-bearing ores in a seawater environment. Cleaner copper recovery is 95%, with gold recovery of 90%. The final concentrate grade is targeted at 26.5% Cu. Four 100 m³ scavenger cells (24 min residence time) recover residual values, with recirculation of 25% to the first cleaner.
• Stage 5: Concentrate Thickening, Filtration & Washing – The final concentrate (30 t/h, 660 t/d) is thickened in a 10 m Hi-rate thickener to 65% solids, then filtered using two Larox horizontal pressure filters (90 m² each). The filter cake is washed with desalinated water from a reverse osmosis plant to remove chlorine and sodium contaminants, achieving 9% moisture. The washed concentrate is stored in a 5,000-ton covered stockpile (7-day capacity) before truck transport to ports.

Additional Interesting Data and Summary

The Domeyko concentrator plant design includes additional technical details critical for project evaluation. The flotation circuit uses a total installed power of 42.9 MW across 82 equipment items. Rougher flotation tests confirmed 92.01% Cu recovery and 72.69% Au recovery at a feed P80 of 150 µm using seawater. The regrind circuit (Vertimill VTM-3000) reduces concentrate to 45 µm to liberate fine sulfides. Jameson cells in the cleaner stage are essential for producing a final concentrate grade of 26.5% Cu from lower-quality chalcopyrite ores, particularly in the presence of pyrite and phyllosilicates where lime depression is limited. Tailings are thickened to 65% solids using three high-torque thickeners (45 m diameter, torque 14 MN-m) located at the storage site 13 km away, with an elevation gain of 275 m. The tailings storage facility (Sector 4) has a capacity of 310 Mt. Water management employs a seawater pond (24-hour capacity) and multiple recovery ponds (45,000 m³ each) to recycle process and drainage water. Concentrate handling uses two Larox horizontal filters (90 m²) to achieve 9% moisture with desalinated water washing. The project’s economic impact is underpinned by annual copper production of 39.1 kt and gold production of 67 koz, based on the PEA mine plan. Sustainability initiatives include high-density tailings to minimize water loss and energy consumption, and the use of untreated seawater reduces freshwater demand in an arid region. Reagent consumption is optimized for seawater chemistry, including 20 g/t main collector (256 t/yr), 100 g/t lime (1,280 t/yr), and 20 g/t corrosion inhibitor (256 t/yr). Total grinding media consumption is 60 g/t (768 t/yr for SAG and ball mills). The plant layout covers 7 hectares northeast of the mine, integrating all major unit operations. Future studies will focus on optimizing reagent selection for cleaner flotation and confirming equipment sizing through pilot testing. The Domeyko project represents a significant advancement in seawater sulfide flotation technology, offering a blueprint for sustainable copper-gold processing in water-constrained regions.

Key Processes: Flotation, Gravity Separation, SAG Mill, Ball Mill, Crushing

Target Commodities: Gold, Copper