The companies may have to shut production at their mines once stockpiling capacity has been reached while they wait for the rail line to reopen, which could be by Christmas day, according to the Australian Rail Track Corporation.

The accident reveals the vulnerability of the coal supply chain linking the emerging Gunnedah Basin of NSW with the port.

It comes as Whitehaven was ready to overcome problems with its longwall automation and preparing to ramp up production.

The Narrabri mine initially asked approval for 420 return truck movements along a 65km length of the Kamilaroi Highway, while Boggabri wanted permission for 156 return truck movements.

But after a trial at Narrabri lasting 48 hours, Whitehaven decided to abandon the trucking option citing concerns about the risks of interaction with other heavy traffic on the highway.

Idemitsu is also trying to avoid the forced production shutdown, though trucking from Boggabri is looking less likely because of the impact on local communities.

“Idemitsu Australia Resources is progressing with a review of options available to minimise the impact to the operation of its Boggabri Coal mine following the recent derailment of a coal train on the Mungindi to Werris Creek rail line,” the company said in a statement.

“As part of this review, the company is seeking input from the Boggabri community regarding the implementation of a short-term, temporary road haulage solution from the mine to the Gunnedah coal handling and processing plant, until such a time that the rail line is back in full service.”

The ARTC advised on December 5, 2012 that the rail line and Cox’s Creek Bridge, which were extensively damaged as a result of a train derailment, were expected to be back in operation later this month.

Idemitsu said the Boggabri mine was investigating alternate options to continue operations until the rail line was fully repaired and back in service.

“Idemitsu Australia Resources would like to reassure the community that if the road haulage option is implemented, it would only be a temporary solution until the rail line is fully operational,” it said.

Open cut coal mining is currently conducted at Boggabri via hydraulic excavators in a strip mining configuration.

Coal from the pit is loaded into rear dump trucks and transported to the run of mine crusher pad.

It is then crushed and loaded into B-double trucks for transport to the rail load-out facility via a private 17km haul road.

The coal would then be railed to the Port of Newcastle for export.

Open cut mining methods at Boggabri Coal allow the full recovery of all coal down to the Merriown seam.

In 2009, 1.55 million tonnes of coal was exported from Boggabri.

The mine employs about 150 full-time employees and contractors.

Meanwhile, Whitehaven Coal has decided to reschedule longwall maintenance at Narrabri in response to the derailment.

The move is a blow for Whitehaven, which only just ironed out longwall automation problems and was attempting to gear up production to 65 cutting hours per week.

Whitehaven managing director Tony Haggarty said the track closure did not affect its open cut operations or the Gunnedah CHPP.

“We do not have capacity at Gunnedah CHPP to handle all Narrabri coal,” he said.

“However, short-term trucking would reduce the impact of the rail closure and allow production at the Narrabri mine to continue while the track repairs are completed.

“Other actions, including rescheduling of required longwall maintenance at Narrabri, reconfiguration of stockpile facilities, maximising coal deliveries from the open cut operations and optimising shipping schedules, are also being put in place.”