Ero Copper (TSX: ERO, NYSE: ERO) was down near 6% early Monday after overnight Sunday saying its Tucuma Operation has suffered a power disruption following a severe windstorm that occurred in the southwest region of the Carajas Mineral Province in Para State, Brazil on October 5.

The company said its workforce is safe and there has been no damage to infrastructure.

The regional power grid, including the main 230kV transmission line servicing the region, sustained damage during the storm, resulting in a loss of power to more than 200,000 residents as well as major industrial users, Ero said in a statement.

Power had since been fully restored to residential communities and partially restored to industrial consumers. The owner and operator of the transmission line had advised that full power restoration to industrial consumers, including Tucuma, is expected within two weeks.

"While the extent of the impact will depend on the timing of full power restoration, Ero Copper remains well-positioned to manage this temporary disruption and will provide further updates as the situation develops," the company added.

Ero's statement also noted the power disruption at Tucuma had impacted the milling, flotation and filtration circuits within the processing plant. Mining and crushing operations remained unaffected, with ore continuing to be placed on the run-of-mine and crushed ore stockpiles. The company expects the primary impact will be on the ramp-up schedule of the processing plant, and in turn, full-year production results at Tucama.

National Bank, which has a Sector Perform rating and Target of C$33 on the stock, sees the impact as "negative."

The bank said its Sector Perform rating considers Ero's near-term growth profile, incremental exploration potential and expansion opportunities offset by near-term cost pressures and a premium P/NAV valuation (owing to initial high-grade years of production at Tucuma reflecting discounted EV/CF multiples). Its outlook reflects lower 2024 production than company guidance and higher costs associated with the ramp-up of Tucuma.

National noted Ero traded at 1.53x NAV compared to peers at 1.12x and 6.0x EV/2025E CF compared with intermediate peers at 7.4x. The bank's $33.00 target is based on a multiple of 1.3x NAV (50%) + 7.0x EV/2025E CF (25%) + 7.0x EV/2026E CF (25%).