TORONTO – Barrick Gold's proposal to take full control of its Acacia Miningc unit to resolve a long-standing tax dispute with Tanzania has drawn the ire of Acacia's minority shareholders, who may have the ultimate vote on a deal.

Barrick's offer values Acacia at $787-million, a near 11% discount to its Tuesday close and 42% below Barrick's own audited valuation of Acacia's assets in its 2018 annual report.

"Either their auditors are not doing their job properly and they should have taken an impairment at the 2018 year end, or this is a false statement. Which is it?” an Acacia shareholder, speaking on condition of anonymity, told Reuters.

Barrick spun off Acacia into a separate company in 2010, but owns 63.9% of the company.

Barrick's offer follows two years of wrangling over a $190-billion Tanzanian tax bill, which has since been reduced to $300-million.

Even as Barrick has negotiated with the Tanzanian government to resolve the tax dispute on Acacia's behalf, relations between the two companies have soured. Acacia has blamed Barrick for being shut out of the talks, while Barrick has accused Acacia of failing to cooperate with its efforts.

Following Barrick's offer on Tuesday, Acacia said in a statement the government of Tanzania had refused to execute final agreements if Acacia is one of the counterparties.

Under UK rules, an offer for more than 30% of a company's shares requires approval by at least 50% of shareholders unrelated to the deal. But that requirement may be waived if over 50% of the target is held by one shareholder. Barrick did not respond to requests for comment on the matter.

One Barrick shareholder, speaking on condition of anonymity, said Acacia's minority shareholders appeared to have few other options than to accept the offer.

"Take this deal or the company goes on being harassed by the Tanzanian government," the investor said, noting Acacia's minority shareholders may have a little leverage since Barrick "can't do anything with the status quo either . . . Barrick can't sell to a third party, because nobody's going to buy Acacia without an agreement in place."

Shares of Acacia, which owns three mines in north-west Tanzania, opened down 8.4% in London but recovered to close 3% lower at 154.9 pence.

Barrick shares closed 1.5% lower at C$16.01 in Toronto, broadly in line with the S&P/TSX Global Gold Index.

With much of the tax dispute stemming from the period when Barrick fully owned the Acacia assets, a deal by Barrick with the government of Tanzania to retake ownership "feels like bare-faced cheek to us," analysts at Peel Hunt wrote in a note.

Acacia's troubles in Tanzania began after President John Magufuli, nicknamed "The Bulldozer," swept to power in 2015 pledging to secure a bigger share of resource wealth and cut corruption.

The Tanzanian government accused the company of evading taxes for years by under-declaring exports, a claim Acacia has dismissed.

In February, weeks after Mark Bristow, known as a seasoned African operator, became chief executive of Barrick, the company outlined details of a deal with the Tanzanian government to settle the Acacia dispute, including a $300-million payment and a 50:50 split of economic benefits.

The news sent Acacia shares surging to their highest since October 2017, when an initial framework deal was announced, but they have since declined 42%, as a final agreement failed to materialize.

Barrick has offered 0.153 of its own share for each Acacia share, which implies a total consideration of $285-million to the minority shareholders of Acacia.

Barrick has until June 18 to make a firm offer for Acacia or walk away from the deal.