RTCA, which holds a majority interest in Kestrel mine, is monitoring updates from its service providers regarding the expected duration of repairs to the rail system.

The timing of the disruption is a blow for Rio, which earlier this month announced that December quarter hard coking coal production was 9% lower than in 2011 due to the impact of planned dragline maintenance at Hail Creek and a major preparation plant shutdown at Kestrel as part of its mine expansion project.

Kestrel mine operations are in the process of transitioning to Kestrel mine extension as it seeks to access the remaining resources at the site more efficiently.

When the extension is complete, capacity will increase to up to 7 million tonnes per annum with an average of 5.7Mtpa of saleable coal expected over the extended 20-year life of the mine.

The extension is still expected to come onstream in the second quarter of 2013.

The Kestrel mine has also seen its extension costs blow out by $900 million as speculation mounts that it may have to cut jobs.

Rio said 50% of the Kestrel cost overrun resulted from the high Australian dollar, 20% was from higher inflation, while 30% was due to delays and scope changes.

No other RTCA-managed sites were impacted by the damage to the Blackwater rail system, the company said.

“All sites managed by Rio Tinto Coal Australia are operating and working towards normal production,” it said.