Australia’s biggest gold mining company Newcrest Mining said on Thursday that it has rejected a purchase offer of $16.9bn (A$24.6bn) from US-based miner Newmont.

Newcrest’s production increased by more than 14.3% to 2.16 million ounces (moz) in 2022, owing to increased mining and milling rates, according to GlobalData. Meanwhile, output from Newmont fell by a marginal 0.6% year-on-year to 4.3moz in the first nine months of 2022.

Newcrest interim CEO Sherry Duhe said in an interview with Bloomberg that the company “is worth a lot more” than the almost $17bn offered. “The company is not up for sale and this [bid] was unsolicited,” Duhe said, adding that Newcrest has “offered Newmont limited conversations to share a bit more about where we see value in the portfolio, and so obviously that’s with them now to see if they’d like to decide to engage”.

Duhe also mentioned that the company’s copper production might rise to above 50% by the end of the decade due to the metal’s role in the energy transition. Copper mining is currently responsible for a quarter of the company’s revenue.

Newcrest said in a statement: “The board has considered the indicative proposal and has unanimously determined to reject the offer,” according to Reuters. However, it said it is prepared to provide access to limited, non-public information on a non-exclusive basis to Newmont for an improved proposal.

Reuters reported last week that Newmont was open to increasing its $16.9bn bid due to concerns that the offer was too low following recent leadership changes at Newcrest. Sources have said that the US company is not worried about being outbid.

Newmont already stands as the world’s largest gold producer by market value and ounces produced. If it were to prevail in its bid for Newcrest, it would become a gold mining giant, producing nearly twice as much of the metal as its closest rival Barrick Gold.