Mining rates were also moderated at Appin Area 7 to ensure gas concentrations were maintained at safe levels.
Production in the March 2017 quarter was impacted by a longwall move at Dendrobium that was extended by four days and was slow to ramp-up as a result of challenging roof conditions.
FY17 production guidance remains unchanged at 7.9Mt and requires a strong finish to the year, the company said.
A longwall move at Appin Area 9 is scheduled for June.
A drawdown of inventory ensured sales in the nine months ended March 2017 exceeded production by 258,000.
Sales in the March 2017 quarter also included a carryover shipment from the December 2016 half year.
South32’s South Africa Energy Coal saleable production decreased by 11% to 21.5Mt in the nine months ended March 2017.
