[ferro-alloys.com]BHP Billiton says it has not seen a material impact from current global trade tensions on its business but remains cautious in the near term.

"We closely monitor the external environment, in particular the market volatility triggered by current global trade tensions. Though we have not seen a material impact on our business, we remain cautious in the near term," chairman Ken MacKenzie said at the company's annual general meeting in London.

The world's biggest miner reported an eight per cent rise in first-quarter iron ore production on strong Chinese demand for high-grade ore, but cut its fiscal 2019 guidance for copper production citing outages.

BHP declined to give a date on when the Samarco joint venture between BHP and Brazil's Vale could resume iron ore production, after Vale's CEO suggested it could reopen at a third of its capacity at the beginning of 2020.

Operations at Samarco were halted in late 2015 after one of its dams collapsed, killing 19 people and causing one of Brazil's worst environmental disasters.

At an event in Rio de Janeiro on Tuesday, Vale CEO Fabio Schvartsman said "all indications are that there will be no problems and that, by the beginning of 2020, all issues will be overcome and it will be possible to resume operations".

But Mr Mackenzie, however, told a London news conference on the sidelines of the company's annual general meeting on Wednesday that he could not give a date because there were many issues to address, including permits, debt-holders and assessment of the asset's financial viability.

"It's quite complex and we are working through it. Until we can be completely clear on some of these issues, I'd rather not be too definitive," he said.

• [Editor:王可]