Rio Tinto said iron ore shipments from its Australian mining operations are likely to be at the lower end of guidance following disruptions from four cyclones during the first quarter of the year.

Rio Tinto Group’s first-quarter iron ore shipments fell 9% from the year before to a six-year low, after tropical cyclones disrupted exports from its key Australian terminal.

Extreme weather in Western Australia and Brazil during the first quarter has caused Rio Tinto’s iron ore production to fall to the lowest level in six years. The mining giant celebrated a record first quarter for bauxite production.