Atlantic Lithium said that it has twice rejected a takeover approach from its major shareholder Assore International worth just over £200 million.
Assore offered to buy all the shares it does not own at a price of 33p or around a 60% premium to the close yesterday.
Ghana-focused Atlantic said its independent directors committee (IBC) considered the latest approach, which was at the same price as an earlier approach on 2 October, before rejecting it as it did with the first.
In each instance, the IBC concluded the offer undervalued Atlantic Lithium and, "therefore, was not in the best interests of shareholders".
That decision reflected the near-term producer status of the project, the status of the pending investment from the Minerals Income Investment Fund and the positive near-term outlook for lithium project developers, said a statement.
Conditions of the offers also included Atlantic's board unanimously recommending the offer, providing exclusive due diligence to Assore's satisfaction, Foreign Investment Review Board approval and entry into a definitive and mutually acceptable scheme implementation agreement.
Neil Herbert, Atlantic’s executive chairman, said: "Assore, a major African mining company, has been a leading investor and key contributor to the company's success since its listing in London in 2015.
“We look forward to maintaining our strong relationship with Assore as we progress Ewoyaa towards production."
Assore, which is a major mining group in Africa, holds just over 25% of the shares of Atlantic Lithium