Sasol's coal mines subsequently fell short of supplying the stock required for Secunda, prompting the plant to use stockpiles and hampering the impact of efforts to improve its operations.
"Although our efforts to improve SO's stability have yielded some positive results, our mining business improvement efforts have not met our own targets," Sasol said in a statement, stressing that it was a disappointing miss.
The plant's full-year production volumes were now forecast at 6.7-6.8 million tonnes, Sasol said, down from its previous forecast of 7.4-7.5 million tonnes.
The company is now focused on restoring its stockpiles, gradually improving production through increased coal supplies and better safety at its coal mines, where three fatalities led to a hit in production.
It said a further update on its sales and volume outlook would be provided in January.