** Shares of Noronex NRX.AX rise as much as 18.8% to A$0.019, their highest level since April 16

** Stock marks it biggest intraday pct rise since April 10

** The copper explorer says diversified miner South32 S32.AX to buy a 60% stake in Noronex' Cgae Cgae copper project in Botswana for A$5 million ($3.25 million) over five years

** About 4.8 million shares change hands, 5.3 times the 30-day avg

** Stock is up 63.6% YTD, including the session's moves

($1 = 1.5382 Australian dollars)

(Reporting by Anjali Singh in Bengaluru)

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