Antonov has been COO since August 2018.
He has over 20 years' experience in the mining industry and spent 11 years at Kinross Gold, where he worked his way up to director of commercial and supply chain management operations and was part of the leadership team at the Kupol mine in Far East Russia.
He previously worked at Berma Gold, which was acquired by Kinross, where he was director of finance.
Trans-Siberian said Antonov's addition would strengthen its depth, with the board now comprising two executive directors and five non-executive directors, two of whom are independent.
Antonov has entered into a conditional agreement to purchase 80,249 ordinary shares pursuant to the secondary sale.