Cuiaba mine
Cuiabá mine is located in the Iron Quadrangle, which is a geotectonic unit on the southern edge of the São Francisco Craton, comprising Archaean and Proterozoic terrains, and bordered by Neoproterozoic mobile belts. From a regional viewpoint, Cuiabá mine is located in the eastern extension of the Serra do Curral inverted homocline, located on the northeastern edge of the Iron Quadrangle.

Deposit type
Cuiabá is an Archaean BIF-hosted gold deposit that produces sulphuric acid as a processing by-product. It is characterised by hydrothermal alteration of the rocks, with the mineralisation occurring mainly in BIF layers, subordinate quartz veins or in schists. The host to the gold mineralisation in the volcanosedimentary Nova Lima Group that occurs at the base of the Rio das Velhas Supergroup. The upper sequence of the Rio das Velhas Supergroup is the metasedimentary Maquiné Group. The gold mineralisation at Cuiabá has features and characteristics that match the epigenetic orogenic gold deposit model typical of Archaean lode gold deposits.

Mineralisation style
Cuiabá mine’s gold mineralisation is associated with sulphides and quartz veins in BIF and volcanic sequences. Structural control and fluid flow are the most important factors for gold mineralisation with a common association between largescale shear zones and their associated structures. Where BIF is mineralised, the ore appears strongly stratiform due to the selective sul ........

Cuiabá mine
Cuiabá is an underground operation which is located near Sabará, southeast of the city of Belo Horizonte, the capital of Minas Gerais State, in the southeast of Brazil.

The mine currently operates using two main mining methods: sub-level longhole open stoping, and triple stoping. A variant of sub-level longhole stoping with a free face horizontal tunnel is also applied over low inclination high-grade areas. The cut and fill mining method was reintroduced to increase ore recovery. It is applied in the narrow veins below Level 14.1 (Balancão, Galinheiro and Canta Galo orebodies) where the dip is lower. In the Galinheiro footwall, the mining method remains sub-level stoping as the orebody shows a reasonable steep dip and thickness.

All underground production is hoisted to surface through a vertical shaft.

Cuiabá Mine has a shaft system (846m deep) for production and personnel transport, the current nominal airflow capacity is 1,035m3 /s, of which 320m3 /s are refrigerated.

Lamego mine
The Lamego mine is an underground operation within one of the most important metallogenetic provinces in Brazil known as the Iron Quadrangle.

Lamego started operating as a cut and fill mine and migrated to long hole stoping as geology and mining knowledge increased over time. These changes had a positive impact on productivity and costs, keeping the asset competitive and efficient. The changes started in 2014 and are now c ........

Crushing:
There is a primary crushing inside the mine and after that the ore is sent to the surface crushing. Crushing is just a process to reduce size of ore rocks so that it can feed the Mill with a smaller size.

Milling:
Milling process is responsible to reduce ore size so that it assumes a powder size. After that the ore goes through gravimetric concentrators, so the free gold can be taken of the gold. However, approximately 85% of the gold is included in sulfur molecule and is necessary additional processes to recovery it. There is no cyanide solution adding at the milling process.

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