** Shares of South32 S32.AX rise as much as 4.8% to A$3.27, hitting their highest level since April 1

** Stock set for strongest session since mid-October, if current gains hold

** Co's first-quarter manganese output more than doubles from a year earlier to 1.4 mln wet metric tons (wmt) after a recovery in operations

** Total quarterly production beats Visible Alpha's estimate of 1.23 million wmt

** Stock down 3.8% YTD, including the day's moves

(Reporting by Shivangi Lahiri in Bengaluru)

((shivangi.lahiri@thomsonreuters.com))