** Shares of Grand Gulf Energy GGE.AX rise 166.7% to A$0.004, their highest level since November 18, 2024
** Oil explorer eyes biggest pct gain since mid-September 2020
** Oil explorer enters deal with option to get 70% working interest in a petroleum exploration licence covering an area in the Walvis Basin, offshore Namibia
** About 39.2 mln share change hand in their busiest day since April 24, 2023
** Rise in shares help co log YTD gains of ~100%, including the day's move, vs a 25% loss on Friday's close
(Reporting by John Biju in Bengaluru)
((John.Biju@thomsonreuters.com;))