The Santa Rita nickel located near Ipiau in the Bahia state of Brazil is one of the biggest open-pit nickel sulphide mines in the world.
The nickel-cobalt sulphide open-pit mining operation is currently owned and operated by Atlantic Nickel, a wholly-owned subsidiary of Appian Capital Advisory.
Previously owned and operated by Mirabela Nickel, the Santa Rita nickel commenced operation in 2009 but was placed on care and maintenance after six years of operation due to poor market conditions in 2015.
Appian became the owner of the mine by acquiring Mirabela Nickel through the bankruptcy process in 2018 and recommenced mining activities at the site in July 2019.
The first shipment of nickel sulphide concentrate from the mine took place in January 2020, while the second and third shipments were complete by June 2020. The mine produced a total of 30,000 tonnes (t) of nickel concentrate in the first half of 2020 and the total production is expected to reach 105,000t by the year-end.
Appian announced additional underground resources at the mine in June 2020 and a preliminary economic assessment (PEA) for the same is expected to be completed in the third quarter of 2020. The underground operation is expected to extend Santa Rita's mine life to more than 26 years.
Location, geology, and mineralisation
The Santa Rita nickel mine is situated in the state of Bahia in north-eastern Brazil, approximately 6km away from the town of Ipiau and approximately 360km southwest of Salvador.
The nickel-cobalt suphide deposit is located within the Archean-Palaeoproterozoic Itabuna-Salvador-Curaca Belt, which is spread from southeast of Bahia to Salvador and separates the Archaean Gaviao and Jequie blocks from the Serrinha block.
The Itabuna-Salvador-Curaca Belt is the youngest segment present in the Sao Francisco Craton and is made of low-potassium calcalkaline plutonic suite containing intercalated metasediments along with basalt and gabbro.
The mineralised zone in the Santa Rita deposit is spread across the Fazenda Mirabela Intrusion, with widths up to 140m, strike length of more than 2km and it inclines up to 1,000m-deep. The mineralisation consists of granular aggregates of pentlandite with slight violarite. The nickel sulphides are linked with chalcopyrite, pyrrhotite and pyrite, while millerite, cubanite, and mackinawite are the minor sulphides.
Nickel, copper, and cobalt resources at Santa Rita
The open-pit resources at the mine are estimated to be 59.1million tonnes (Mt) grading 0.31% nickel, 0.11% copper, and 0.01% cobalt.
The measured and indicated underground resources of the Santa Rita mine are estimated to be 168Mt grading 0.59% nickel, 0.19% copper, and 0.01% cobalt.
Mining and ore processing at Santa Rita nickel restart project
The conventional open-pit mining method with the drill, blast, load, and haul operations is being implemented at the Santa Rita nickel project.
The run-of-the-mine (ROM) ore is trucked to a nearby processing plant where it undergoes crushing and two-stage grinding in a semi-autogenous grinding (SAG) mill and a ball mill, before passing through a three-stage floatation process.
The concentrated material obtained from the flotation cells is forwarded to a concentrate thickener followed by a Larox filter for the production of the final concentrate product which is packed and trucked for shipping.
The Santa Rita mine is accessed through a sealed road connected to the BR330 main highway located approximately 2km away from the mine site.
The Atlantic coast ports of Ilheus and Aratu are located approximately 143km and 340km away from the project site.
The water requirement for the project is sourced from the nearby Rio de Contas while the potable water is sourced from a water treatment facility located in Ipau.
Atlantic Nickel entered into a three-year offtake agreement for a portion of nickel sulphide output of the Santa Rita, as well as a £31m ($40.8m) financing agreement for the Santa Rita nickel mine restart project with multinational commodity trading company Trafigura in January 2020.