Copper-Silver Recovery Methods at Nowa Sól Project

Source: Unnamed_Company_2 (2026)
Website: https://www.luminametals.pl/nowa-sol

Critical Data

Overview

Lumina Metals Corp. is advancing the Nowa Sól Copper-Silver Project in Lubuskie Province, Poland, with a robust Preliminary Economic Assessment (PEA) that defines a proven, conventional recovery methods flowsheet. The project is designed to process 32,000 tonnes per day (t/d) per concentrator, with two identical facilities (North and South) achieving a combined total of 64,000 t/d. The recovery methods center on primary crushing, semi-autogenous grinding (SAG) and ball milling with pebble crushing, followed by a copper flotation circuit that includes rougher, scavenger, and three stages of cleaning to produce a 26% copper concentrate containing silver. Tailings are dewatered and either sent to a Dry Stack Tailings Facility (DSTF) or mixed with cement for underground backfill. The process design is based on metallurgical testwork and leverages over 60 years of successful operational experience from nearby KGHM mines. Key parameters include a head grade of 1.19% Cu and 36.9 g/t Ag, with target recoveries of 88.75% for copper and 86.64% for silver. The circuit operates 24 hours per day, 365 days per year, with a target grind size of 60 µm (P80). The preliminary site water balance indicates a deficit of 5.7 million m³ per year, which will be managed through mine dewatering and recycled process water. This comprehensive recovery approach ensures high metal extraction while minimizing environmental impact through dry stacking of tailings and extensive water recycling.

Key Process Stages

• Stage 1: Primary Crushing – Fresh mineralized material from underground is crushed using a single conventional gyratory crusher operating at 2,051 t/h with 65% utilization. The product size is P80 of 150 mm, and the crushed ore is conveyed to a stockpile with a total live capacity of 64,000 tonnes. Dust collection systems minimize emissions.
• Stage 2: Grinding Circuit – Crushed ore is fed into a SAG mill (10.4 m diameter × 5.5 m long, 12,000 kW motor) along with process water. Oversize pebbles (+13 mm) are screened and sent to a pebble crusher before returning to the SAG mill. The SAG mill discharge combines with ball mill product in a common sump, then pumped to cyclones. The ball mill (9.2 m diameter × 12.2 m long, 22,000 kW motor) receives cyclone underflow and grinds to a target P80 of 60 µm. The circuit includes a 300% circulating load and provisions for future flash flotation.
• Stage 3: Flotation Circuit – Cyclone overflow at ~33% solids feeds rougher conditioners where collectors (PAX) and frother (MIBC) are added. Rougher and scavenger concentrates are combined and reground in a stirred vertical mill to a P80 of 10 µm. Three stages of cleaner flotation (conservatively designed, though testwork suggests two suffice) produce a final concentrate grading 26% Cu. Retention times are scaled by 2.5 from testwork: rougher 23 min, scavenger 30 min, cleaner 1 – 30 min, cleaner 2 – 20 min, cleaner 3 – 18 min.
• Stage 4: Concentrate Dewatering – The final flotation concentrate (1,761 dry t/d per plant) is thickened to 60% solids using flocculants, then pressure-filtered to 8.5% moisture. Filter cake is stored in an indoor stockpile before being loaded into lined containers or trailers for off-site transport. Dust collection systems control emissions. Thickener overflow is recycled to the process water system.
• Stage 5: Tailings Dewatering and Handling – Flotation tailings (30,239 dry t/d per plant) are thickened to 60% solids and then filtered to 15% moisture using horizontal plate-and-frame filter presses. Filtered tailings cake is conveyed either to a stockpile for truck loading to a Dry Stack Tailings Facility (DSTF) or to a paste plant where cement and water are added for underground backfill. Runoff from the DSTF is collected and reused as process water.

Additional Interesting Data and Summary

Additional technical and economic data from the Nowa Sól Copper-Silver Project PEA further underlines the viability of the recovery methods. The process design is based on a Bond Ball Mill Work Index of 15.6 kWh/t, a Crusher Work Index of 10.0 kWh/t, and an Abrasion Index of 0.200 g, all typical for copper-lead-zinc mineralization. The SAG mill pebble crusher handles 8,000 t/d (P80 75 mm to 14 mm). The flotation circuit operates with a feed solids density of 32.8% w/w and a rougher feed rate of 1,449 t/h. Concentrate regrind mill feed is 8,640 t/d, grinding to a product P80 of 10 µm. The final copper concentrate grade averages 26% Cu with 854 g/t Ag and 4.53% Pb, produced at a concentration ratio of 19.9:1 and a weight recovery of 5.03%. Concentrate dewatering uses a thickener (underflow density 60% solids) and pressure filter (moisture 8.5%). Tailings dewatering achieves a yield of 94.07% with a filter cake moisture of 15%. Environmental considerations are integral to the design: the Dry Stack Tailings Facility minimizes water contamination and land disturbance, while the paste backfill plant reduces underground void risk. Water management is critical—a conceptual water balance shows a deficit of 5.7 million m³ per year per plant, primarily sourced from mine dewatering and recycled process water from thickener overflows and tailings filtrate. Reagents including PAX, MIBC, lime, and flocculants are stored in contained areas with safety systems. The project’s future outlook includes studying alternative crushing technologies and confirming the need for flash flotation. The two-plant configuration (North and South) allows phased ramp-up and operational flexibility. With robust copper and silver recoveries and a flowsheet proven in the region, the Nowa Sól Project is positioned to become a significant European copper-silver producer, leveraging local expertise and sustainable tailings management practices.

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

Target Commodities: Silver, Copper, Lead