** Shares of Great Boulder Resources GBR.AX fall 13.7% to A$0.063, their lowest since June 12

** Stock on track for worst day since March 2023 if trends hold

** Gold explorer announces placement to raise A$12.5 million ($8.00 million) at 6.1 Australian cents per share

** Issue price represents a discount of 16.4% to the stock's last close

** About 2.8 million shares change hands, 1.2x the 30-day average of 2.3 million

** Stock up 46.5% YTD, including moves in the current session

($1 = 1.5620 Australian dollars)

(Reporting by Jasmeen Ara Shaikh in Bengaluru)

((JasmeenAraIslam.Shaikh@thomsonreuters.com;))