** Shares of Australia's Octava Minerals OCT.AX rise as much as 31.8% to A$0.083, their highest level since February 3

** Stock last up 9.5%, on track for its biggest intraday pct rise since August 21

** Co to exercise its option to acquire the Byro Critical Minerals Project located in Western Australia

** Initial research shows excellent rare earth, lithium, and vanadium extraction yields with scope to improve leaching

** About 4.6 mln shares traded so far, 4.6 times the 30-day avg

** Stock is down 44.8% YTD, including the session's moves

(Reporting by Anjali Singh in Bengaluru)

((anjali.singh2@thomsonreuters.com;))