The consortium bidding to take London-listed copper miner Kaz Minerals private has increased its buyout offer to 780p a share as it seeks to win over minority shareholders.

Nova Resources, which is fronted by Kaz chairman Oleg Novachuk and billionaire metals tycoon Vladimir Kim, made a 640p cash offer in October for the 61 per cent of the company they did not already own.

However, the bid was rejected by some of the company’s minority shareholders, who said it did not reflect the miner’s fair value and growth potential.

“The new improved bid of 780p is just about acceptable in our view,” said Liberum analyst Ben Davis.

The company’s shares have been trading above the offer price for the past couple of months as the price of copper has soared to its highest level in seven years. The shares closed at 773p on Wednesday. They have risen 17 per cent this year and are up nearly 64 per cent over the past 12 months.

Mr Novachuk said the increased £3.7bn offer, which has been recommended by an independent board committee, represented a “highly attractive return” for shareholders “ensuring they have the opportunity to realise in cash the value of their investment at a compelling valuation”.

“We believe that Kaz Minerals' long-term interests are now best served as a private organisation,” he said in a statement.

However, it is not clear that the improved bid will be enough to secure the backing of minority shareholders. RWC Partners said this week that a bid of 1,000p a share would be more acceptable to minority shareholders.

“As we forecast that Kaz Minerals will generate more than $5.5bn of ebitda over the next 3 years, it is our opinion that the £7.80 per share offer price still materially undervalues the company,” RWC Partners said in a statement on Thursday.

“Therefore, based on current circumstances, we do not believe this latest offer price represents good value for minority shareholders.

The offer has not been declared final, giving Nova Resources the option to increase its bid again.

There are two important milestones for the Nova Resources bid. In order to delist the company they will need to obtain undertakings to accept from 75 per cent of shareholders. And at 90 per cent they can squeeze out remaining shareholders, forcing them to surrender their shares.

Nova has already secured irrevocable undertakings from 50 per cent of shareholders.

Kaz Minerals was trading close to £10 two years before the company announced plans to buy a huge copper deposit in the east of Russia from Chelsea Football Club owner Roman Abramovich and partners for close to $1bn.

Baimskaya is regarded by some minority investors as one of the mining industry’s most exciting under-developed copper prospects even though its budget has blown out to around $8bn.

As the world shifts to cleaner forms of power an increasing amount of copper will be needed to wire the electrification of the global economy.

In a recent report Deutsche Bank estimated that more than 4m tonnes of annualised production capacity are needed to be approved and constructed by 2030 to meet a projected supply gap.