Mendell is part of the group’s advisory board and has been involved with the company since its initial public offering in March 2015.
Zoetic said Mendell has been instrumental in identifying natural resources projects and helping establish the CBD business, particularly by seeing the potential of the nitrogen-hydrogen gas discovery in Kansas.
“Since we announced our new strategy two weeks ago, Paul has been an enormous support,” said chief executive Nick Tulloch.
“He has an in depth understanding of both sides of our business and, in particular, no one has as much knowledge of our natural resource assets, and of how to monetise them, as Paul.
“He is popular with our team and business partners and I am looking forward to working with him to deliver value to shareholders.”
The news comes just days after Highlands Natural Resources changed its name to Zoetic to reflect its shift away from oil and gas towards its CBD operations, which have taken off since launch in April.
The company said its executive management committee now includes CEO Tulloch, Trevor Taylor as chief strategy officer, Antonio Russo as chief revenue officer, Eric Anderson as senior vice president and Melvyn Davies as interim chief financial officer.