** Mount Ridley Mines MRD.AX surges as much as 78.1% to A$0.054, highest since October 12, 2022
** Rare earths explorer appoints Allister Caird as CEO
** Caird previously served as head of critical minerals at copper and gold explorer Locksley Resources LKY.AX
** Around 86.9 million shares traded, 6.4x the 30-day avg
** MRD last up 75%, surging ~2,033% YTD
(Reporting by John Biju in Bengaluru)
((John.Biju@thomsonreuters.com;))