Up 308% in 2025, this high-flying ASX mining stock is sinking on Monday. But why?

Investors in Felix Gold Ltd (ASX: FXG) have had a stunning run in 2025.

Shares in this ASX mining stock have rocketed by more than 300% since early January, reaching $0.365 apiece at the time of writing.

For context, the All Ordinaries Index (ASX: XAO) is up by…