As a result of having increased its mineral reserve and mineral resource estimates, TSX- and NYSE-listed Ero Copper Corporation reports that, at the same cut-off grades, the total proven and probable mineral reserves at its MCSA mining complex in Bahia state, Brazil, have increased by 13%.

This includes a significant 56% increase in mineral reserves within the deepening extension zone of the Pilar mine that remains open for potential expansion.

The miner, in 2021, updated the National Instrument 43-101- (NI 43-101-) compliant mineral reserve and resource estimates on its 99.6%-owned MCSA mining complex and its 97.6%-owned NX gold mine, located in Mato Grosso state, Brazil.

The updated mineral reserve and mineral resource estimates incorporate drilling activities and mining depletion on the properties through September 30, 2021.

The 2021 update also led to a 32% increase in measured and indicated mineral resources (25% increase in proven and probable reserves) for the NX gold mine, at the same cut-off grades.

These increases, Ero reports, are driven by extensions of the Santo Antonio vein and the maiden mineral reserve estimate for the Matinha vein that remains open for potential expansion and is expected to become an integral part of the operation in the coming years.

As for the deepening extension zone of the Pilar mine, Ero reports that good drill results continue to demonstrate significant year-on-year increases in the grade and contained copper since the mine’s initial discovery in 2018. This further supports Ero’s decision to construct a larger 6.3 m finished diameter external shaft (compared with a previously envisaged 4.5 m) to increase the value of the mine.

At this mine, proven and probable mineral reserves within the deepening extension zone increased by 56%, to 194 200 t of contained copper (11-million tonnes grading 1.76% copper), compared with 124 600 t of contained copper (7.4-million tonnes grading 1.68% copper) in 2020.

Also, measured and indicated mineral resources, inclusive of mineral reserves, within the deepening extension zone increased by 55% year-on-year to 217 100 t of contained copper (10.4-million tonnes grading 2.08% copper), compared with 140 000 t of contained copper (7.5-million tonnes grading 1.86% copper) in 2020.

Further, the inferred mineral resources within the deepening extension zone increased by 37%, to 130 100 t of contained copper (6.1-million tonnes grading 2.14% copper), compared with 94 800 t of contained copper (4.5-million tonnes grading 2.12% copper) in 2020.

MCSA MINING COMPLEX
At the MCSA Mining Complex, Ero reports that proven and probable mineral reserves increased by 13%, to 607 100 t of contained copper (59.3-million tonnes grading 1.02% copper), compared with 536 000 t of contained copper (50.5-million tonnes grading 1.06% copper) in 2020.

Also, the measured and indicated mineral resources, inclusive of mineral reserves, increased 6% to 1.22-million tonnes of contained copper (104.7-million tonnes grading 1.17%), compared with 1.15-million tonnes of contained copper (102.8-million tonnes grading 1.12% copper) in 2020.

The inferred mineral resources of the MCSA Mining Complex increased 21%, to 473 400 t of contained copper (43.3-million tonnes grading 1.09% copper), compared with 390 600 t of contained copper (39.2-million tonnes grading 1% copper) in 2020.

NX GOLD MINE
At the NX gold mine, proven and probable mineral reserves increased 25%, to 306 800 oz of contained gold (1.1-million tonnes grading 8.64 g/t gold), compared with 244 700 oz of contained gold (862 000 tonnes grading 8.83 g/t gold) in 2020.

Here the measured and indicated mineral resources, inclusive of mineral reserves, increased by 32% to 357 300 oz of contained gold (1.08-million tonnes grading 10.28 g/t gold), compared with 269 900 oz of contained gold (770 000 tonnes grading 10.9 g/t gold) in 2020.

Within the Santo Antonio vein, proven and probable mineral reserves increased by 13% to 277 500 oz of contained gold (958 000 tonnes grading 9.01 g/t gold), compared with 244 700 oz of contained gold (862 000 tonnes grading 8.83 g/t gold) in 2020.

Within the Santo Antonio vein, measured and indicated mineral resources, inclusive of mineral reserves, increased by 20% to 322 400 oz of contained gold (950 000 tonnes grading 10.56 g/t gold), compared with 269 200 oz of contained gold (763 000 tonnes grading 10.97 g/t gold) in 2020. This was driven primarily by conversion of inferred mineral resources delineated in 2020.

Within the Matinha vein, the maiden mineral reserve estimate with probable mineral reserves of 29 400 oz of gold (146 000 tonnes grading 6.26 g/t gold), while inferred mineral resources increased by 79% to 104 200 oz of contained gold (310 000 tonnes grading 10.47 g/t gold), compared with 58 200 oz of contained gold (149 000 tonnes grading 12.15 g/t gold) in 2020.

Ero CEO David Strang says that, as a core tenet of Ero’s organic growth strategy, the company is pleased to see its investment in exploration continue to generate a pipeline of high-return actionable growth projects across Ero’s portfolio.

“Looking ahead to 2022, our in- and near-mine exploration plans for the year include expanded drilling activities in the upper levels of the Pilar mine in support of a two-mine system, extending the known limits of the high-grade Vermelhos mine main orebodies to depth and continuing to define several growth projects throughout the MCSA Mining Complex and the NX gold mine.”