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RDM Gold Mine
Producing gold in Brazil
RDM commenced operations in 2014 as an open pit mine.
Minas Gerais, Brazil
~52,600 oz gold
$1,685-$1,870 per oz AISC
556 Koz @ 0.99 g/t gold
132 Koz @ 1.27 g/t gold
Mining and processing
Open pit / CIL plant
Estimated mine life
~5 years with existing reserves
RDM is located in Minas Gerais State, Brazil, about 560 km north of the state capital city of Belo Horizonte. Equinox Gold assumed ownership of RDM in March 2020 through its acquisition of Leagold Mining.
The RDM deposit was discovered in 1986 and operated as an open-pit heap leach mine until 1997. Operations recommenced with a carbon-in-leach (CIL) plant in early 2014, producing around 60,000 ounces of gold per year. RDM experienced a number of operating disruptions in Q1 and Q2 2022 as the result of regulatory issues related to the expansion of the mine’s tailings storage facility. In July 2022, Equinox Gold made the decision to focus on processing low-grade stockpiles and perform owner mining to reduce costs while the tailings storage facility expansion is underway. As a result, RDM production was lower and costs higher in 2022 than in normal years. For 2023, Equinox Gold has resumed owner-operated mining but on a smaller scale than in previous years to reduce capital costs.
Production at RDM in 2023 is forecast at 50,000 to 60,000 ounces of gold at all-in sustaining costs between $1,685 to $1,870 per ounce of gold sold. Sustaining capital for 2023 of $13 million is primarily for a tailings facility raise and installation of a tailings thickener, and also for open-pit waste stripping. Equinox Gold has not budgeted any non-sustaining capital at RDM for 2023.
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Mining and Processing
Mining is performed with conventional truck and shovel operations at a rate of approximately 2.9 Mt per year with a strip ratio of approximately 7:1 (waste:ore). While open-pit mining has historically been performed by a mining contractor, in Q3 2022 RDM transitioned to owner-operated mining to reduce costs.
Ore is delivered to an 8,000 tonnes-per-day crushing and grinding circuit and is processed with gravity concentration and a standard CIL plant. Gold recovery averages around 86%.
Exploration and Geology
The RDM gold deposit occurs in the north-south trending Araçuaí Fold-Thrust Belt along the eastern margin of the São Francisco Craton, a major Archean-age basement block that underlies more than one million square km in eastern Brazil. The Araçuaí Fold Belt is 15 km to 45 km wide and consists of a series of meta-volcanic/meta-sedimentary rocks of late Archean to late Proterozoic age.
The principal host for RDM gold mineralization is the quartz-muscovite schist of the Riacho dos Machados Group (RMG). The mineralization occurs in a belt of hydrothermally-altered rock developed along a district-scale shear zone. Mineralization occurs in the hydrothermal/shear zone and gold grades are closely related to the sulphide content, especially arsenopyrite.
Exploration at RDM under previous ownership was negligible. Open pit expansion potential exists along trend to the north and south and underground potential exists down dip where mineralization has been intersected by widely spaced drill holes. In addition, the mine is located on a 30-km trend of alteration and mineralization in the RMG that has not been comprehensively drill tested.