Up 61% in a year, why is this ASX 300 gold stock getting hammered on Thursday?

S&P/ASX 300 Index (ASX: XKO) gold stock St Barbara Ltd (ASX: SBM) is sliding today.

St Barabara shares closed yesterday trading for 47 cents. In morning trade on Thursday, shares are changing hands for 45 cents apiece, down 3.8%.

For some context, the ASX 300 is down 0.7% at…