LUSAKA (Reuters) -Copper miners remain bullish on the metal's future prospects even as a looming 50% U.S. tariff creates short-term price volatility, Barrick Mining Corp CEO Mark Bristow said in Zambia, where the company is expanding its operations.

U.S. President Donald Trump said on Wednesday he would impose the new copper tariff from August 1 to promote domestic development of an industry critical to defence, electronics and automobiles.

The announcement propelled U.S. Comex copper futures to an all-time high.

But analysts predict prices outside the U.S. could be dragged down as countries like Chile, the world's top copper producer and the United States' biggest supplier, shift supplies elsewhere in response to the tariffs.

"The copper price is going to be unstable just like everything else in the world, and we will have to get out of this instability," Bristow told journalists in Zambia's capital, Lusaka, late on Thursday.

However, he said that, despite the fallout from U.S. tariff policy decisions, copper's long-term trajectory remained unchanged.

"We are seeing a shortage in supply, and growing demand particularly with the data centres, the movement to cleaner energy, and just generally as the emerging markets start investing in industrialisation, which is a big consumer of copper," Bristow said.

"So, everyone is in agreement that the copper demand is outgrowing the supply side," he said.

Barrick, the world's second-largest gold producing company by output after Newmont, is currently investing in boosting its copper production.

It is carrying out a $2 billion plan to double annual output from its Lumwana copper mine in Zambia to 240,000 metric tons by 2028. Barrick will also extend the mine's life to 2057.

"Most of the copper industry today is only looking at marginal expansion," Bristow said. "We are very excited that we made this commitment to invest ahead of this tightening."