The Riotinto concentrator in Huelva Province, Spain, processes copper sulfide material using conventional froth flotation, with current operations at above 15 Mtpa following a three-phase expansion and upgrade program.
The Riotinto concentrator processes copper sulfide mineralized material using conventional froth flotation to produce a copper concentrate. The plant employs a combination of existing equipment associated with the historical operations as well as expanded and upgraded facilities. The processing department staff consists of 115 people, 10 of whom work in management and supervisory positions, with the balance occupying positions assigned to middle management and operating personnel. The concentrator is managed through an ongoing improvement system which aims to maintain or improve the historic metallurgical results.
Since refurbishment and re-commissioning in June 2015 (Phase 1), the process was upgraded and successfully expanded to 9.5 Mtpa (Phase 2) and is currently operating at above 15 Mtpa. The upgrade to the current capacity was achieved through the Proyecto Riotinto 15M Upgrade Project, with new equipment added to the existing Phase 2 plant design and the resulting plant design modified as well as reconfigured. As part of this project, it was established that acceptable upgrading and recoveries were achievable with rougher and cleaners only, utilizing the new flotation cells on cleaning duty.
In the primary crushing plant, 15 Mtpa of copper mineralized material is processed from open-pit mining in two crushing lines, a gyratory and a jaw crusher. The gyratory crusher has a capacity of 1,700–2,200 t/h and processes 10 Mtpa with a product size of P80 165 mm. The primary crushing product is fed into a live crushed mineralized material stockpile with a capacity of approximately 126,000 tonnes. Mineralized material from the crushed ore stockpile is then fed into a conventional SAG Mill circuit that processes 2,050 t/h. The SAG mill discharges through a trommel with a port opening of 12 mm and into the secondary ball mill circuit to further reduce the mineralized material to a P80 of 160-200 µm.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Plant Feed Grade | 0.49 | % Cu | Design criteria for 15 Mtpa operation |
| Total Plant Feed | 15,000,000 | t/y | Design criteria for 15 Mtpa operation |
| Hours per Year | 8,760 | h | |
| Crushing Plant Availability | 65 | % | Existing case includes 22% downtime due to mining |
| Rest of Plant Availability | 85 | % | |
| Crushing Plant Operating Hours | 5,694 | h | |
| Gyratory Crusher Feed | 10,000,000 | t/y | Combined throughput of 15 Mtpa |
| Jaw Crusher Feed | 5,000,000 | t/y | Combined throughput of 15 Mtpa |
| Crusher Feed Rate (Gyratory) | 1,756 | t/h | |
| Crusher Feed Rate (Jaw) | 878 | t/h | |
| Crusher F100 | 1,000 | mm | |
| Crusher F80 (Gyratory) | 399 | mm | |
| Crusher F80 (Jaw) | 400 | mm | |
| Primary Crusher (Gyratory) | 1 x 460 | kW | |
| Primary Crusher (Jaw) | 1 x 250 | kW | |
| Secondary Crusher (Existing) | 3 x 325 | kW | Cone |
| Crusher Product P80 | 65 | mm | Coarser product, suitable for SAG milling |
| Primary Grinding Configuration | ABC + 2 Stages Ball | Not applicable | ABC + 2 Stages Ball |
| Grinding Operating Hours | 7,446 | h | |
| Grinding Feed Rate | 2,015 | t/h | |
| SAG Mill | 23 | MW | New in Open Circuit |
| Pebble Crushing | 2 x 300 | kW | Cone crusher |
| SAG Mill Trommel Opening | 12 | mm | |
| Grinding Product P80 | 160-200 | µm | |
| Regrind Mill 1 | 2.4 | MW | Ball |
| Regrind Mill 2 | 0.9 | MW | |
| Regrind Specific Energy | 19 | kWh/t | |
| Regrind Power Required | 2,780 | kW | |
| Regrind Power Available | 3,000 | kW | |
| Rougher Flotation Volume | 1,500 + 644 + [300] | m³ | Five 300 m³ cells + forty-six 14 m³ cells + three 100 m³ cells [optional] |
| Cleaner 1 Volume | 300 | m³ | Re-tasked cells |
| Copper Recovery | 84.3 | % | Design criteria |
| Mass Pull | 1.9 | % | |
| Concentrate Thickener Feed Solids | 15 | % | By weight |
| Concentrate Thickener Diameter | 9 | m | Two thickeners operating in parallel |
| Concentrate Thickener Underflow Solids | 55 | % | By weight |
| Process Plant Manpower | 115 | people | 10 in management and supervisory positions |
| Differential Flotation Capital Cost | 92.24 | $ M | Estimated |
| Differential Flotation Operating Cost | 8.91 | $/t | Estimated |
Overview
The Riotinto processing facility has been developed through a series of phases. Phase 1 involved refurbishment and re-commissioning in June 2015, followed by Phase 2 which expanded the process to 9.5 Mtpa. Ramp-up of Phase 1 and construction activities for Phase 2 started to overlap in September 2015 when Phase 2 engineering and construction started. At the end of December 2015, the processing plant achieved an annualized throughput target, and in this same period Phase 2 reached 92% completion with final construction activities and tie-ins to existing operations pending. Atalaya declared commercial production in February 2016. The current Phase 3 upgrade increased throughput to above 15 Mtpa.
Tables within the technical report detail the equipment summary for the current 15 Mtpa operation and the equipment modifications summary. New equipment includes a 23 MW SAG mill with pebble crushers to process coarsely crushed product and preparation for the existing ball milling circuit, primary mill classification using 10 x 600 mm cyclones with overflow directly to flotation and underflow to the existing ball milling circuit, and rougher flotation consisting of existing 46 x 14 m³ cells, a 300 m³ cell, and 4 x new 300 m³ tank cells. The primary SAG mill is in open circuit with pebble crushers. Modifications were made to existing equipment, including modifying the double deck screen chutes in the screening area, reconfiguring the 300 m³ pre-cleaner in rougher flotation, and changes to accommodate a smaller regrind mill.
Key Process Stages
The primary crushing stage processes 15 Mtpa of copper mineralized material from open-pit mining in two crushing lines. The gyratory crusher processes 10 Mtpa with a product size of P80 165 mm, while the jaw crusher processes the remaining feed. The crushed product is placed on a live stockpile with a capacity of approximately 126,000 tonnes.
Primary grinding is conducted in a conventional SAG mill circuit processing 2,050 t/h. The SAG mill is in open circuit, with pebble crushers, and the discharge passes through a trommel with a 12 mm port opening. The product reports to the secondary ball mill circuit which reduces the material to a P80 of 160-200 µm.
Classification of the SAG mill product is achieved via 10 x 600 mm cyclones. The overflow goes directly to flotation, while the underflow reports to the existing ball milling circuit.
Conventional froth flotation is conducted using mechanically forced air flotation cells in rougher and cleaner circuits. The rougher flotation consists of existing 46 x 14 m³ cells, a 300 m³ cell, and 4 x new 300 m³ tank cells, making a combined rougher volume of 1,500 m³. Cleaner 1 flotation uses re-tasked cells, with a volume of 300 m³.
The final cleaner concentrate, at approximately 15% solids by weight, is pumped to two 9 m diameter concentrate thickeners operating in parallel, where the slurry is thickened to 55% solids by weight.
Additional Interesting Data and Summary
Life of Mine production data presented in the technical report demonstrates that the upgraded facility is consistently achieving recoveries and final concentrate grades both higher than the original design criteria expectations.
Metallurgical laboratories are maintained on site, delivering daily results to the metallurgical and process teams. State of the art equipment and well-trained personnel deliver results that go through routine quality controls to ensure accuracy and that all processes are performing with design specifications. The analytical laboratory crew reports directly to the site General Manager.
To process the massive sulfide material associated with the San Dionisio and San Antonio deposits, a modified recovery circuit will need to be designed. The main economic elements found in the deposits are copper, zinc, lead, and minor amounts of gold and silver. Preliminary testwork on these ores indicates that ultra-fine grinding (<20 microns) followed by differential flotation may be required to achieve acceptable metal recovery and produce saleable concentrates. The process would likely produce three concentrates: copper concentrate, zinc concentrate, and lead concentrate.
The mineralized material would likely be processed by conventional bulk flotation to recover copper, lead, and minor amounts of gold and silver into a bulk concentrate. The rougher bulk concentrate would be cleaned and further processed to separate the copper and lead to produce a lead concentrate and a copper concentrate. The final tailings from the zinc flotation circuit would be pumped to the tailings storage facility. A simplified flowsheet is one of the possible differential flotation schemes, with additional grinding and flotation to recover the polymetallic material. This circuit would produce the rougher bulk concentrate with additional grinding and flotation.
Capital cost requirements for the differential flotation circuit are estimated at $92.24 M, with operating costs for the circuit estimated at $8.91/t. Most of the additional operating cost would be attributed to the ultrafine grinding. Additional engineering and metallurgical testwork will be required to properly establish specific design criteria and refinement of these economics.
Key Processes
- Primary crushing using a gyratory crusher (1,700–2,200 t/h) and a jaw crusher, processing 10 Mtpa and 5 Mtpa respectively.
- Open circuit SAG milling with a 23 MW mill and pebble crushers, followed by a secondary ball mill circuit to a P80 of 160-200 µm.
- Conventional froth flotation using mechanically forced air cells in rougher and cleaner circuits, with 1,500 m³ rougher volume and 300 m³ cleaner 1 volume.
- Concentrate thickening in two parallel 9 m diameter thickeners, from 15% to 55% solids by weight.
- Differential flotation circuit planned for polymetallic material, with ultra-fine grinding (<20 microns) to produce copper, zinc, and lead concentrates.
Source: Riotinto , 2023 Technical Report, 2023.
Project website: Riotinto, 2023 Technical Report
