** Shares of Great Northern Minerals GNM.AX rise 20% to A$0.036, their highest level since March 16
** Shares on track to gain most since Feb 18 if trends hold
** Mineral explorer enters binding exploration lease and option to purchase agreement to buy Iron Butte Gold–Silver Project in Nevada, U.S.
** About 2.3 mln shares change hands, 4.4x the 30-day average of 526,318
** Stock down 20% YTD including current moves
(Reporting by Jasmeen Ara Shaikh in Bengaluru)
((Jasmeenaraislam.Shaikh@thomsonreuters.com;))