The first hole to test the south extensions of the Vermelhos deposit hit 39.8m at 5.57% copper, including 21.9m at 9.43%.
Vermelhos is under development and the company is aiming for production in the fourth quarter.
Ero has stockpiled 9,802 tonnes grading 4.37% copper at surface from gallery development in the UG1 mining area.
At the operating Pilar underground mine, Ero intersected 18m at 6.28% copper among the highlights in the deepest intercepts yet, drilled about 235m below previously known mineralisation.
The company has also started a district-wide airborne geophysical survey to help prioritise regional targets.
It produced 4,845t of copper in the March quarter from its Pilar and openpit Surubim operations.
It ended the quarter with US$29.3 million cash.
Ero Copper shares have doubled since debuting on the TSX in October at C$4.75.
They reached a fresh high of $9.91 intraday and closed up 30c to $9.85, up about 30% year-to-date and capitalising it at $831.9 million.
