Overview

Deposit type

• Banded iron formation

Summary:

The Minas-Rio deposit, comprising the Serra do Sapo operation and Itapanhoacanga project, is hosted in a Proterozoic metasedimentary sequence located in the Serra do Espinhaço Belt. The main iron bearing lithologies are concentrated in a unit of the Serra do Sapo Formation, which consists of a haematite-quartz-sericite schist, referred to as itabirite.

The outcrops occur along a narrow ridge of 12km length in NNW-SSE strike and moderately dipping (25o) to the East. All these sequences are controlled by thrust fault systems that are responsible for local duplications, inversions or suppression of the beds.

The Itabira District is located some 80 km to the ENE of Belo Horizonte in Minas Gerais, within an outlier of the Rio das Velhas and Minas Supergroups that are infolded into the surrounded Archaean gneissic complex which separates them from the main Quadrilátero Ferrífero. The operating mines exploit ore developed in the Cauê Itabirite at the base of the Itabira Formation of the Minas Supergroup. This unit is exposed over a continuous strike length of 11 km in a series of synformal and antiformal structures that collectively define a larger synclinorium.

The iron ores of the Itabira district occur both as hard high grade, 67% Fe hematite and as friable lower grade, 45-50% Fe itabirites that must be upgraded. In addition, the orebodies are mantled by canga, (detrital and lateritic material). The hematite ores are interpreted to be due to hypogene enrichment of the itabirites, while the friable ores are the result of supergene leaching of silica and iron enrichment. The geological resource is stated at 1.3 Gt of hematite ore and 2.8 Gt of friable ores.

The oxide facies is characterised by millimetre thick banded layers rich in white quartz with alternating layers rich in specularite, haematite and locally magnetite, with colour ranging from dark grey to dark red. Depending on the weathering intensity, iron-bearing lithologies are physically classified as friable itabirite, semi-friable itabirite and itabirite. The grade range for material classified as itabirite is between 25 and 60 %Fe. Iron grades higher than 60% are defined as haematite. Depending on the alumina and phosphorous grades, it is further separated into high alumina itabirite, mineralised canga or waste.

The friable itabirite is totally disaggregated with quartz and lamellar/granular haematite being completely liberated. It is often located at the top of the sequence, close to the surface and strongly weathered resulting from supergene enrichment with increased iron grade. Semi-friable itabirite is a partially decomposed rock and disaggregates when struck with a hammer; it is a transition between friable and unweathered rock. Normally, it occurs at the base of friable itabirite or with lenses interlayered in friable or unweathered itabirites.

Itabirite represents the fresh rock, with a dark grey colour and a fine grain size. It is unweathered, mostly with a pervasive schistosity and tectonic banding composed of quartz and dark grey metallic haematite, with rare concentrations of massive haematite. In the southern portion of Serra do Sapo, the itabirite has an average thickness of approximately 60 m, and thicknesses up to 220 m are encountered in the central to northern areas.

Mining Methods

• Truck & Shovel / Loader

Summary:

Iron ore operation in Brazil, Minas-Rio, consists of an open-pit mine and beneficiation plant.

Comminution

Crushers and Mills

Summary:

DRY PROCESS STRUCTURES:
• Primary crushing
• Secondary crushing
• HPGR.

The adoption of Metso's Vertimill grinding mills in Anglo American's Minas-Rio System resulted in a 30% reduction in electric power consumed during regrinding operations.

For the Anglo American venture, Metso supplied 16 Vertimill VTM-1500-WB model grinding mills. The circuit comprises two regrinding lines, each composed of 8 mills, each with a power of 1.1 megawatts (MW), and four cyclone batteries for grading iron ore.

Processing

• Desliming
• Crush & Screen plant
• Flotation
• Magnetic separation
• Dewatering

Summary:

In Brazil, company have developed the Minas-Rio operation (100% ownership), consisting of an open- pit mine and beneficiation plant, which produces a high grade pellet feed product, with low levels of contaminants. The iron ore is transported through a 529-kilometre pipeline to the iron ore handling and shipping facilities at the port of Açu.

Minas-Rio’s pellet feed product also commands a premium price, as its ultra-low contaminant levels and high iron content (67% Fe content) are sought after by steel producers who are seeking to minimise emissions while boosting productivity.

WET PROCESS STRUCTURE:
• Primary grinding
• Flotation
• Regrinding
• Concentrate thickener
• Tailings dam.

Traditionally, iron ore content has been removed from lower grade ore-bearing material through flotation, a physical-chemical process of separating particles of different granulations, which are induced or repelled when in contact with water. At Minas-Rio, we have introduced magnetic separation to the flotation process. This is a disruptive technology that uses magnetic separators to concentrate fine and ultrafine iron particles (ultrafines). The technology allows us to do away with expensive flotation columns that necessitate prior mud removal to work efficiently and is enabling higher metal recovery, along with lower levels of contaminants.

Minas-Rio’s magnetic separation plant is due to start operations in October 2022, with metal recovery expected to increase by c.4%. This enhanced treatment of the ore, brought about by greater efficiencies in the concentration process, will boost overall iron ore output. Pellet feed production is now projected to increase by 1.5 million tonnes per year (Mtpa) – against c.700,000 tpa using conventional flotation methods. Moreover, this has been achieved without the need to raise the feed rate of the plant, while the volume of tailings directed to the dam has also been reduced by 1.5 Mtpa.

Minas-Rio is focused on increasing tailings storage capacity. The tailings filtration plant project is on track for completion by early 2026 and alternative, additional disposal options continue to be studied.

Pipelines and Water Supply

Summary:

Water for the operation (i.e., ore processing, product and waste transport via pipeline, dust control and human consumption, etc.) is obtained from the Peixe River, groundwater wells and pit dewatering. Water such as precipitation and wastewater are additionally collected, treated and reused (i.e., dust control, processing, plant irrigation, etc.), or discharged.

The ~525 km Minas-Rio pipeline takes iron ore slurry (solids suspended in water) from the mine processing plant to an export facility at the costal port of Açu, from where the ore is shipped to China. The world’s longest pipeline of its kind, it crosses 32 municipalities in the states of Minas Gerais and Rio de Janeiro.

The pipeline uses a system of pumps and valves to speed up or slow down the ore stream, taking four days to reach its destination at 6 km per hour. The water that carries the mineral is collected from a river in nearby Dom Joaquim municipality and has reduced the water supply to local residents. Corrosion of the pipe caused two major spills in March 2018 that discharged nearly 950 tonnes of iron ore pulp in nearby creeks and river basins.

Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
Director of Operations	Evilmar José Fonseca		Mar 22, 2024
Mine Infrastructure Manager	Gustavo Sperandio de Sá		Mar 22, 2024
Mine Operations Manager	Juliano Alves dos Reis		Mar 22, 2024
Mine Planning Manager	Frederico Santana Castro		Mar 22, 2024
Planning Manager	Gustavo Oliveira Gomes		Mar 22, 2024
Study Manager	Ana Flavia Lara		May 30, 2024
Technical Services Manager	Aurélio Garcia		Mar 22, 2024