Overview
Nestled in the mineral-rich state of Minas Gerais, Brazil, the Minas-Rio iron ore operation stands as a flagship project for global mining giant Anglo American plc. This world-class facility represents one of the largest integrated iron ore mining and processing projects developed in the 21st century. Commissioned in 2014, the Minas-Rio complex was designed with a nominal capacity to process 48 million tonnes of ore annually, producing a premium, high-grade iron concentrate essential for global steel production. The project’s significance extends far beyond its impressive scale; it is a marvel of modern engineering, integrating a sophisticated mineral processing plant with a record-setting 529-kilometer slurry pipeline that transports the final product to the Port of Açu on Brazil’s Atlantic coast. This pipeline is the longest of its kind for iron ore concentrate in the world, a critical piece of infrastructure that defines the project’s logistics and economic viability. Operating in a challenging topography, the facility transforms itabirite ore—a lower-grade iron-bearing rock—into high-quality Direct Reduction Pellet Feed (DRPF) and Blast Furnace Pellet Feed (BFPF) for international markets. The ongoing operation, backed by a comprehensive NI 43-101 Technical Report, underscores Anglo American’s commitment to long-term, sustainable resource development in Brazil, leveraging cutting-edge technology in crushing, grinding, and flotation to maximize recovery and product quality while implementing significant projects to enhance yield and environmental stewardship.
Key Process Stages
The Minas-Rio beneficiation plant employs a complex and highly automated circuit designed to upgrade itabirite ore into a saleable iron concentrate. The process is a sequential journey of size reduction, liberation, and separation, optimized for efficiency and recovery. Here is a detailed breakdown of the key stages in this advanced mineral processing flowsheet.
- Stage 1: Primary & Secondary Crushing: Run-of-mine ore is delivered by haul trucks to one of two dump pockets, each fitted with an 800 mm grizzly. An apron feeder directs the material to a primary jaw crusher at a design rate of 8,440 tonnes per hour, reducing the ore to approximately 150 mm. The product is then screened, with oversize material undergoing secondary crushing to achieve a target size of about 25 mm before being conveyed to a crushed ore stockpile.
- Stage 2: High-Pressure Grinding Rolls (HPGR) & Primary Grinding: The crushed ore is further comminuted by multiple 4.8 MW High-Pressure Grinding Rolls (HPGRs), a highly energy-efficient technology that reduces the ore to about 1 mm. The HPGR product is fed into the primary grinding circuit, which consists of two parallel ball mills. Each massive mill is 7.9 meters in diameter and 12.2 meters long, powered by a 15 MW motor, and operates in closed circuit with banks of hydrocyclones. This stage grinds the ore to a target P80 of 120 micrometers, liberating the iron minerals from the waste gangue.
- Stage 3: Two-Stage Desliming: The ground slurry reports to a two-stage desliming cyclone plant. The primary stage uses 8 clusters of 11 cyclones, with the overflow feeding a secondary stage of 8 clusters of 60 smaller (100 mm) cyclones. This process removes fine, low-value silicate slimes (ultra-fine particles) that can interfere with downstream separation. The combined underflow, containing the coarser valuable material, advances to flotation, while the slime-rich overflow is sent to the tailings thickener.
- Stage 4: Reverse Cationic Flotation: The deslimed feed enters a twin-stream flotation circuit, the heart of the chemical separation process. The slurry is conditioned in large 180 m³ tanks where reagents are added: starch acts as a depressant for iron oxides, and amine acts as a collector for the unwanted silica. The circuit is configured with rougher, cleaner, and scavenger banks of 160 m³ tank cells. The amine-coated silica particles attach to air bubbles and are skimmed off as froth (tailings), while the iron-rich pulp sinks and becomes the concentrate. This “reverse flotation” method is highly effective for producing a super-high-grade iron product.
- Stage 5: Concentrate Regrinding & Thickening: The final flotation concentrate is classified in cyclones ahead of a regrind circuit comprising 16 vertical mills (Vertimills). The cyclone overflow, ground to an ultra-fine P80 of 40 micrometers, reports to a large concentrate thickener. This fine grinding is crucial not for liberation, but to reduce particle size for safe hydraulic transport, minimizing the risk of settlement in the long-distance pipeline. The thickener underflow is pumped at 69.5–71.0% solids to homogenization tanks.
- Stage 6: Slurry Pipeline Transport: This is the defining stage of the Minas-Rio operation. A concentrated slurry is pumped into a 529 km buried pipeline—the world’s longest for iron ore. The system uses positive displacement piston diaphragm pumps at two stations to maintain a flow velocity of ~1.7 m/s. The slurry is conditioned to a pH >11 to prevent corrosion and settlement. The pipeline itself contains approximately 80 hours of production volume, acting as a massive buffer storage system as it traverses varied topography to the coast.
- Stage 7: Filtration & Ship Loading: At the Port of Açu, the slurry is dewatered in a dedicated filtration plant. It is first thickened to about 76% solids, then filtered using 14 large ceramic filters, each with a 144 m² filtration area, to achieve a final moisture content of approximately 9%. This is critical to meet the Transportable Moisture Limit (TML) for safe ocean shipping. The filter cake is stockpiled and later loaded onto vessels for export to global customers.
Critical Data
The operational excellence of the Minas-Rio circuit is quantified by its key performance indicators. The table below summarizes the critical technical and production data extracted from the NI 43-101 Technical Report, highlighting the scale and efficiency of this world-class operation.
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Nominal Plant Capacity | 48.0 | Mt/a | Original design capacity |
| Average Plant Feed Rate | 5,995 | t/h | Recent operating average (2020-2025) |
| Average Concentrate Production | 2,887 | t/h (dry) | Recent operating average |
| Primary Ball Mill Power | 15.0 | MW (each) | Two mills, each 7.9m x 12.2m |
| HPGR Unit Power | 4.8 | MW (each) | Multiple units in operation |
| Target Primary Grind Size (P80) | 120 | µm | Ball mill circuit product |
| Target Regrind Size (P80) | 40 | µm | Vertimill circuit product for pipeline |
| Pipeline Length | 529 | km | Longest iron ore concentrate pipeline globally |
| Pipeline Flow Velocity | ~1.7 | m/s | To prevent solids settlement |
| Specific Energy Consumption | 17-19 | kWh/t (dry concentrate) | Total for beneficiation and filtration |
| Plant Availability (“Up Time”) | 85% | – | Beneficiation plant average |
| Concentrate Solids to Pipeline | 69.5 – 71.0 | % | Thickener underflow density |
Additional Interesting Data and Summary
Beyond the core processing stages, the Minas-Rio operation is characterized by continuous innovation and a strong focus on sustainability and risk management. Since 2022, several key metallurgical enhancement projects have been implemented. The magnetic separation plant, commissioned in November 2022, processes a feed stream at 737 t/h and contributes a 38% yield to the final concentrate, improving overall recovery. The Vertimill regrind project has been crucial in refining the concentrate size for safer pipeline transport. Looking forward, a major tailings filtration project is under construction, with commissioning slated for Q1 2026. This initiative is central to the site’s water management strategy, aiming to increase water recycling, reduce the wet tailings footprint, and enhance dam safety—a critical aspect of modern ESG (Environmental, Social, and Governance) compliance in mining.
The operation’s water management is a model of efficiency, with approximately 85-90% of process water demand met through internal recycling from the tailings storage facility (TSF) thickener overflow and filtrate recovery. Freshwater is sourced from the Peixe River system, but the closed-loop design minimizes external abstraction. Energy consumption, while significant due to the energy-intensive grinding and pumping processes, is managed through a reliable supply from the regional CEMIG grid, with specific consumption averaging 17-19 kWh per tonne of dry concentrate produced.
The 529-km pipeline is not just a transport solution but an engineering asset requiring meticulous care. Its integrity is maintained through a rigorous monitoring regime, including a “smart pig” inspection every five years to measure wall thickness and bi-annual “pigging” to clear sediment. Following an incident in 2018, the monitoring system was significantly upgraded with advanced leak detection and pump monitoring technologies. At the port, the filtration plant ensures the product meets strict shipping moisture specifications, with the TML monitored quarterly. Interestingly, the filtration plant makes the port site “water positive,” as it extracts all transported process water, which must then be treated and managed.
In summary, the Minas-Rio operation is a testament to large-scale, integrated mineral processing. It successfully combines brute-force comminution with sophisticated chemical separation and groundbreaking logistics to deliver a high-quality product from a challenging ore body. The project’s ongoing investments in magnetic separation, fine grinding, and tailings filtration demonstrate Anglo American’s commitment to optimizing recovery, reducing environmental impact, and ensuring the long-term, sustainable operation of this pivotal asset in the global iron ore supply chain.
Source: NI 43-101 Technical Report | Feasibility Study | Project: Rio Property | Date: November 2025
Further Reading
- Major Mines & Projects | Minas-Rio Mine
- Minas-Rio Iron Ore Project, Rio de Janeiro, Brazil
- Minas-Rio: World’s longest iron concentrate pipeline
Consolidated report summaries
The following former standalone pages about this operation were consolidated here on October 25, 2026. They are retained for source traceability; dates and figures reflect each report’s own effective date and may be superseded by the current information above.
Minas-Rio Property — 2025 Technical Report
This technical report describes the Minas-Rio iron ore processing plant, nominally designed for 48 Mt/a, currently operating at reduced capacity with concentrate transported 529 km by pipeline to the Port of Açú.
Report context
The technical report, dated 3 November 2025, covers the Minas-Rio Property located in the State of Minas Gerais, Brazil. The mineral-processing plant was commissioned in 2014 with a nominal capacity of 8,440 t/h or 48 Mt/a. As of the report, the plant is treating up to 4.5 Mt/a of ore and producing about 2.0 Mt/a of high-grade iron-rich concentrate for export. The final concentrate is transported 529 km by pipeline to the Port of Açú, where the concentrate slurry is filtered prior to storage on stockpiles awaiting vessels for delivery to international customers.
Four grades of product have been delivered historically: Direct Reduction Pellet Feed (DRPF) at 26.4%, Blast Furnace Pellet Feed (BFPF) at 63.4%, New Blast Furnace Pellet Feed at 10.1%, and Special Blast Furnace at 0.1%. Only DRPF and BFPF have been produced since 2024.
Processing route
Crushing and grinding
Mined ore is delivered by trucks to one of two dump pockets, each with an 800 mm sizing grizzly on top of the crusher pocket, with an apron feeder and jaw crusher receiving discharge from the dump pocket at a rate of 8,440 t/h. The primary crushed product at about 150 mm is screened with secondary crushing reducing the size to about 25 mm ahead of the crushed ore stockpile. The crushed ore is further reduced to about 1 mm through multiple 4.8 MW HPGR crushers discharging into mill feed bins.
The HPGR product is delivered to the primary grinding circuit consisting of two parallel ball mills, each in closed circuit with eight hydrocyclones. Each mill is 7.9 m diameter and 12.2 m in length with installed power of 15 MW. The hydrocyclone underflow returns to the mill whilst the overflow at P80 120 µm reports to the desliming plant.
Desliming
The slurry is deslimed in two stages. The primary stage consists of 8 clusters of 11 cyclones, with the overflow reporting to a secondary stage consisting of a further 8 clusters of 60 100 mm cyclones each. The overflow from the second stage of desliming reports to the tailings thickener and is discarded to the tailings storage facility. The combined underflow products from each desliming stage report to the flotation plant.
Flotation
The flotation circuit consists of twin streams, each with two 180 m³ conditioning tanks followed by 160 m³ tank cells configured as rougher, with primary and secondary cleaners followed by primary and secondary scavengers. The rougher tails are delivered to the tailings thickener. This configuration can be reconfigured to suit the metallurgical characteristics of the ore being treated. Reagent addition consists of starch (iron depressant) and amine (collector) added to the conditioner tanks. The final cleaner concentrate is the final product, with the secondary scavenger tails being discarded to the tailing thickener.
Regrinding and concentrate handling
The final flotation concentrate reports to classification cyclones ahead of 16 vertical regrind mills (in two streams), with the correctly sized cyclone overflow at approximately P80 40 µm reporting to the single concentrate thickener. The thickener underflow at between 69.5% and 71.0% solids is pumped to homogenization tanks, which feed the concentrate pipeline to the port at the desired solids concentration. The concentrate fine grinding is to reduce the likelihood of settlement within the pipeline.
Tailings
The desliming cyclone overflow and the flotation tails are delivered to the single tailing thickener with lime (pH control) and flocculant addition. The thickener underflow reports to the tailings storage facility and the overflow is recycled as process water.
Pipeline transport
The 529 km pipeline from the plant to the port is constructed from suitable quality unlined steel piping with cathodic protection and is designed for a service life of 20 years. The pipeline has 324 km of 26-inch outside diameter (660 mm OD) piping, followed by 166 km of 24-inch piping (610 mm OD), with the final 39 km of 26-inch (660 mm OD) piping delivering to the filter plant. There are two pump stations: Pump Station #1 (PS#1) located at the mine site, about 2 km from the treatment plant, and Pump Station #2 (PS#2) located 247 km from PS#1. PS#1 has 4 agitated storage tanks, 2 charging pumps and 13 positive displacement piston diaphragm pumps. PS#2 consists of one re-mix agitated tank (normally bypassed), a charge pump and 14 positive displacement piston diaphragm pumps. The system is designed to operate continuously at a throughput range of 2,800–3,550 dry t/h of concentrate. The pipeline contains approximately 80 hours of production when full. The pipeline is buried along most of its route. The highest point is about 1,000 masl, with the beneficiation plant at approximately 700 masl and the filter plant at about 10 masl. To reduce the likelihood of settlement, the contained solution is conditioned to pH greater than 11 and pipeline velocity is controlled to about 1.7 m/s. A pipeline “smart pig” is inserted every five years to measure wall thickness, and a “pig” is inserted every six months to clear buildup.
Filter plant
The filter plant located at the port receives slurry from the pipeline at between 68% and 72% solids. The facility consists of two stages of dewatering: thickening and filtration using ceramic filters. Slurry is thickened to about 76% solids with addition of flocculant and coagulants. The thickened slurry is stored in tanks prior to filtration on 14 ceramic filters, each with a 144 m² filtration area. The target final moisture content is about 9%. The transportable moisture limit (TML) for the concentrate is typically 9.7–9.8% moisture. The recovered water from the thickener and filters is clarified and treated for reuse or discarded to the submarine outfall.
Metallurgical projects
Several enhancement projects have been implemented since 2022, as reported in the testwork and project descriptions. The magnetic separation project has been commissioned and has improved the yield to final concentrate. The Vertimill project is operational and delivers improved yields with a reduced risk of pipeline settlement. The first phase of the tailings filtration project for water control and improved tailings management is in construction and is to be commissioned in the first quarter of 2026.
Recent performance (historical operating data)
The crushing plant has an “up time” averaging 65% whilst the beneficiation plant “up time” is 85%. The average plant feed rate is 5,995 t/h, while the average concentrate production is 2,887 t/h (dry) for the period January 2020 to June 2025. The magnetic separation plant, commissioned in November 2022, has a feed rate of 737 t/h and a yield of 38% to final concentrate.
Power and water
Power is supplied from the regional CEMIG 138 kV transmission network. The beneficiation plant and filtering operations consume approximately 160–170 MW, equivalent to an average specific energy consumption of 17–19 kWh/t (dry) of concentrate. The largest consumers are the HPGR grinding units, ball mills, and flotation air systems.
Raw water is sourced from the Peixe River system via a 40 km pipeline, supplemented by reclaim water from the tailings storage facility and recovered filtrate from the dewatering plant. Approximately 85–90% of total water demand is met by internal recycling.
Reagents
Major consumables include flocculants, dispersants, amines, and starch-based depressants used in magnetic concentration and reverse flotation. Lime and coagulants are used for pH control and water treatment. Filter cloths, grinding media, and mill liners represent key operational consumables.
Key reported parameters
| Parameter | Unit | Design | Actual (Jan 2020–Jun 2025) | Testwork/Project |
|---|---|---|---|---|
| Plant nominal capacity | t/h | 8,440 | 5,995 (average feed) | – |
| Plant nominal capacity | Mt/a | 48 | ~4.5 (current ore treated) | – |
| Concentrate production | t/h (dry) | – | 2,887 (average) | – |
| Concentrate production | Mt/a | – | ~2.0 (current) | – |
| Primary crusher product | mm | ~150 | – | – |
| Secondary crusher product | mm | ~25 | – | – |
| HPGR product | mm | ~1 | – | – |
| Ball mill diameter | m | 7.9 | – | – |
| Ball mill length | m | 12.2 | – | – |
| Ball mill installed power | MW | 15 | – | – |
| Hydrocyclone overflow P80 (primary grinding) | µm | 120 | – | – |
| Regrind cyclone overflow P80 | µm | ~40 | – | – |
| Concentrate thickener underflow solids | % | 69.5–71.0 | – | – |
| Pipeline throughput range | dry t/h | 2,800–3,550 | – | – |
| Pipeline length | km | 529 | – | – |
| Pipeline diameter (section 1) | mm (inch) | 660 (26) | – | – |
| Pipeline diameter (section 2) | mm (inch) | 610 (24) | – | – |
| Pipeline diameter (section 3) | mm (inch) | 660 (26) | – | – |
| Pipeline velocity | m/s | ~1.7 | – | – |
| Pipeline operating pH | – | >11 | – | – |
| PS#1 piston diaphragm pumps | number | 13 | – | – |
| PS#2 piston diaphragm pumps | number | 14 | – | – |
| Slurry solids to filter plant | % | 68–72 | – | – |
| Thickened solids to filters | % | ~76 | – | – |
| Ceramic filters | number | 14 | – | – |
| Filter area per filter | m² | 144 | – | – |
| Target final moisture | % | ~9 | – | – |
| TML for concentrate | % | – | 9.7–9.8 (typical) | – |
| Crushing plant “up time” | % | – | 65 (average) | – |
| Beneficiation plant “up time” | % | – | 85 (average) | – |
| Power consumption | MW | – | 160–170 | – |
| Specific energy consumption | kWh/t (dry concentrate) | – | 17–19 | – |
| Water recycling | % | – | 85–90 | – |
| Magnetic separation plant feed | t/h | – | 737 | Commissioned Nov 2022 |
| Magnetic separation plant yield | % | – | 38 | Commissioned Nov 2022 |
Project website: https://www.angloamerican.com/media/press-releases/2024/03-12-2024
Technical qualifications
The report notes that the processing plant flowsheet information is presented as a simplified flowsheet (Figure 17.1) sourced from Anglo American, 2024a. Performance data is presented from January 2020 to June 2025 as historical operating statistics (Figures 17.3 and 17.4, sourced from Anglo American, 2024a). Metallurgical enhancement projects are described as implemented since 2022, with the tailings filtration project in construction and to be commissioned in the first quarter of 2026. The pipeline design information includes a note that following an incident in March 2018, the pipeline monitoring system was upgraded. The report explicitly states that the process water circuit operates on a closed-loop recycling system minimizing freshwater abstraction. The Qualified Person’s opinion states that the process plant is suitable for treating the Minas-Rio ores and producing a high-grade iron ore product suitable for pelletizing or sintering and feed for conventional blast furnace and direct reduction furnaces.
Source: Anglo American plc NI 43-101 Technical Report – Minas-Rio Property, State of Minas Gerais, Brazil, 3 November 2025, Sections 17.0–17.8.
