Reed has been with the company in the role of chief executive officer for more than 10 years.
Dr Geoff Loftus-Hills, chairman, commented: "Mr Reed's most recent contribution was the successful sale of Aviva's Kenyan gold and base metal assets to African Barrick Gold.
"The Board would like to wish Mr Reed all the best for the future."
Aviva completed the sale of Aviva Mining Kenya to African Barrick Gold placing it in a strong position to take advantage of new opportunities that are under review.
The initial A$20 million received by Aviva for the sale of AMK equates to about A$0.12 per issued Aviva share and reflects the net proceeds for this transaction.
There is a further payment of $10 million due to Aviva if a National Instrument 43-101 Indicated resource of 3 million ounces or more is declared over Aviva Mining Kenya's project areas.
The funding from the sale provides certainty of cash and allows the company to assess its strategic growth options for its coal-based projects in Botswana.
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