Barrick last week gained more time to make a formal bid for the 36.1% of Acacia it doesn't already own, and said it had identified "significant risks" after conducting due diligence of Acacia's assets, adding it expected to record a material impairment to its carrying value of Acacia in the current quarter.

Acacia said yesterday it strongly disagreed with Barrick's view of its life-of-mine plans and saw "no reasonable basis" for Barrick's proposed adjustments.

It also said Barrick's takeover proposal seemed to ignore the value of its exploration and development assets, and said Barrick's intervention in negotiations in Tanzania "had the effect of undermining Acacia".

Acacia said Barrick had hand-delivered a letter from the Tanzanian government's negotiating team acting chairman last month saying it would not execute final agreements if Acacia was a counter-party.

"Acacia acknowledges that this potentially represents a material development in respect of Acacia's status with the GoT, and accordingly has been seeking engagement with the GoT to confirm their position," it said.

It said Barrick's acquisition would be "an attractive solution for all key stakeholders" subject to an offer price which was fair.

"In the absence of a recommendable offer from Barrick, Acacia's preferred outcome is to continue to seek a negotiated settlement with the GoT … which would allow for the lifting of the export ban and resumption of full operations at Bulyanhulu, whilst continuing to operate at North Mara and Buzwagi in the ordinary course, and continuing to demonstrate its long-term commitment to Tanzania, its people and the mining industry going forward," Acacia said.

The company said its Tanzanian operations had continued to perform and while there was the potential threat of further environmental enforcement action, it noted the mines had "faced a series of environmental issues since pre-2010 at which time the business was wholly-owned by Barrick".

Barrick has said it would engage with Acacia's minority shareholders to gain support for its proposed exchange ratio of 0.153 Barrick share for every Acacia share.

Barrick, which merged with Africa-focused Randgold Resources at the start of the year and has become the world's second-biggest gold miner, has seen its share price rise 16.17% since then.

Acacia shares are down 0.55% year-to-date.