Mining giant Anglo American has turned down a plea from BHP to push back the deadline for a massive takeover bid.

The two companies have been locked in negotiations since Wednesday May 22, discussing a potential £39billion deal to take over Anglo American. Facing a strict cut-off at 5pm on Wednesday, Australia's BHP is under pressure to either present a concrete offer or abandon its pursuit.

Earlier on Wednesday, BHP made a last-ditch effort to extend the negotiation period, citing ongoing talks. BHP proposed several "socioeconomic measures" aimed at addressing concerns about its bid and requested additional time to further these discussions with Anglo American.

The company has consistently suggested that Anglo American should divest its South African operations, a move that has drawn sharp criticism from the South African government and resistance from Anglo American itself.

In a recent statement, BHP said: "BHP believes that the proposed measures it has put forward provide substantial risk protection for Anglo American shareholders and supplement the significant value uplift that Anglo American shareholders will receive from the potential combination."

"BHP believes a further extension of the deadline is required to allow for further engagement on its proposal. This announcement does not amount to a firm intention to make an offer and there can be no certainty that an offer will be made."

Anglo American has firmly rejected a proposal for an extension, stating on Wednesday that there is "no basis" for it. The company said in a statement: "BHP has not addressed the board's fundamental concerns relating to the disproportionate execution risk associated with the proposed structure and the value that would ultimately be delivered to Anglo American's shareholders."

The statement continued: "Also taking into consideration detailed feedback from the board's extensive engagement with Anglo American's shareholders and stakeholders, the board has therefore unanimously concluded that there is no basis for a further extension to the Pusu (put up or shut up) deadline."

If the merger between these two giants were to go ahead, it would create the world's largest copper miner, controlling 10% of the global market. Anglo American's significant copper reserves are highly coveted, especially as the metal is crucial for developing low-carbon technologies like solar farms and electric vehicles.

Earlier in the month, Anglo American also revealed plans to dismantle major parts of its operations and significantly decelerate the development of a £7billion fertiliser mine in North Yorkshire.