BHP's bid for Anglo American underlines the growing appetite for energy transition metals like copper from miners who must become more aggressive to secure new projects or risk missing out, investors and mining CEOs said on Wednesday.

The bid by the world's biggest listed miner for Anglo is expected to whet appetite for more deals in the sector whether it goes ahead or not, they said.

"There is clearly a preference for buying over building because costs have ramped up so much in the past few years," said Ben Cleary of Tribeca Investment Partners, which is an investor in Anglo American.

"BHP ... have been telling you for a long time that they love copper. Rio the same. In terms of their portfolio skew they are still very heavily weighted to iron-ore ... you are going to see more deals," he said, speaking at the AFR Mining Summit in Perth.

Anglo has twice rejected overtures by BHP, whose deadline to make a third offer expires later on Wednesday. Instead, Anglo has pledged to break up its company to lower costs.

Whether Anglo's management decide to engage with BHP on Tuesday, investors expect more interest in the sector as copper prices, which hit a record above $11 000 a tonne on Monday, climb and encourage new projects.

Rising prices will only make competition for copper assets more intense, said Brett Beatty, partner and managing director Australia, of private equity company Resource Capital Funds.

Beatty said he had faced internal questions over whether RCF had overpaid for the 11.9% stake in Botswana's Khoemecau copper mine that it bought for $70 million in 2019.

That stake was sold when China's MMG bought the mine for $1.88-billion six months ago, making it worth some $224-million, roughly a two-fold return.

“It’s a market where you have to take risk and you’ll be rewarded for it, but if you sit on the sidelines you’re going to miss out,” he said.

Given that lithium prices have begun to recover from rock bottom lows, for companies with the funding, now is a good time to buy, said Joshua Thurlow, head of lithium at Australian diversified miner Mineral Resources.

"M&A's on people’s minds. It’s at that point in the cycle. If you can be counter cyclical ... you could argue this is a good time to do it," he told Reuters.

"But also sometimes it takes a lot of gusto and a major balance sheet strengthening process to be able to do it," he added.

MinRes embarked on an acquisition spree of significant stakes in Australian lithium developers last year.

“As we continue to look around the goldfield and more prospective areas we will continue to make deals if and when possible," he added.

Beyond copper and lithium, there is even interest in unloved nickel whose prices have been hit by a surge in Indonesian supply.

Wyloo Metals will in coming weeks put its Western Australian nickel operations on care and maintenance.

"For us we are trying to see beyond the next 6 to 12 months to the next 10 to 15 years," CEO Luca Giacovazzi said.

"We are always acquisitive and we are always looking for a longer term opportunity ... As a family office that is really chasing assets that produce yield, it’s an interesting time for us to look at opportunities in the market."