The fresh and final offer is up from a previous bid of 780p per share made in February and a first attempt made in October proposing 640p per share.
Commenting on the improved bid, Novachuk said Nova had listened to shareholders unhappy with the previous offers.
Copper is in high demand for use in renewable energy and electric vehicles, but new deposits are rare and increasingly difficult to recover.
“Copper market dynamics have evolved since the announcement of the original offer in October 2020, and the final increased offer fully reflects this change,” Novachuk added.
Prices for the metal have shot up in the last six months, rising to a 10-year high of almost $9,500 a tonne before easing to about $8,680 on Thursday.
Click here for an interactive chart of copper prices
Analysts at Peel Hunt were not impressed by Nova’s increase, but wrote it would “probably mute the pressure for a further increase” from investors.
“This increase feels similar to the last (the increase to 780p from 640p), in that it moves the offer to roughly where the share price is (840p as of Thursday’s close), rather than providing a knockout blow,” the experts wrote.
World’s top copper prospect
KAZ Minerals bought the Baimskaya copper mine in eastern Russia in 2018 from a group of investors including Chelsea soccer club owner Roman Abramovich.
The company’s stock dived after announcing the acquisition, hit by investor concern over Russian political risk, even though the mine is regarded as one of the world’s most significant underdeveloped copper prospects.
Costs of developing the mine are estimated at almost $8 billion and Nova noted on Friday that among the project’s risks there are potential cost blowouts, increased working capital requirements and liabilities related to long-term logistics contracts.
“In this context, Kaz Minerals’ long-term interests are best served as a private organisation,” Novachuk said.
Shares in Kaz Minerals were up almost 3% to 864p in London on Friday by 1pm local time, leaving the company with a market capitalization of £4.1 billion.