The update features a 13% increase in total proven and probable reserves at MCSA to 607,100t of contained copper hosted in 59.3Mt grading 1.02% copper, with a 56% increase within the Deepening Extension Zone of the Pilar Mine to 194,200t of contained copper hosted in 11Mt grading 1.76% copper. 

At the NX Gold Mine, reserves increased 25% to 306,800oz of contained gold hosted in 1.1Mt grading 8.64g/t. 

"The meaningful growth of our asset base, as reflected in our 2021 mineral reserve and resource update continues to demonstrate our ability to deliver organic growth and generate shareholder value through exploration," said Ero Copper CEO David Strang.

Strang highlighted the continued expansion of the Deepening Extension Zone which continued to exceed the company's expectations with year-on-year growth in the high-grade superpod through ongoing drilling since 2018.

"These results support our decision in 2021 to undertake a larger redesign of the new external shaft. The redesign does require a greater upfront investment but will, over time, enhance the project's value and provide optionality over the long-term as we continue to look to increase overall production volumes from the Pilar Mine," said Strang.

The update was well-received by analyts. "Alone the update is positive — but more important will be the five-year guidance for production, operating costs, and capex which will be released with Q4 financial results," said BMO Capital Markets analyst Jackie Przybylowski in a research note.

Shares in Ero Copper are trading at C$18.93, valuing the company at $1.7 billion.