The deal now hangs on shareholder approval, which is expected to be received at a meeting next week.
Aviva announced in late April that it would sell the 1.3 billion ton Mmamantswe coal resource to African Energy Resources for $A3.5 million.
Acquiring 100% of the license from joint venture partner Mawana Minerals was one of two remaining conditions on the sale.
Mawana shareholders approved the sale of the license but the exchange was awaiting ministerial approval.
Under the transaction with Mawana, Aviva made an initial payment for the license of $US30,000 in May 2013 and will make a further payment of $270,000 to secure the sale.
“Aviva is pleased to have obtained ministerial approval satisfying another condition precedent to the sale of the Mmamantswe coal project and completing the purchase transaction with Mawana,” Aviva chief executive officer Lindsay Reed said.
“Aviva believes consolidation of coal resources in Botswana is important for the development of the coal sector.
“The transaction is a good outcome for Aviva shareholders but also enhances the sector development outlook for African Energy and Botswana.”
Aviva became involved in the Mmamantswe project in 2007 and identified the 1.3Bt resource, which includes a probable reserve of 895 million tons.
It has completed several studies on the project and carried out a major water drilling program.
It announced in October that the environmental impact statement had been issued.