Quick thinking by workmates prevented an employee from suffocating when he was sucked into wheat during the unloading of the silo in May 2000.

The NSW Industrial Relations Commission heard how the man's colleagues placed a tube in his mouth which allowed him to breathe during a five-hour rescue operation.

The 25-year-old worker was helping to move bulk grain from the 65,000 tonne silo to a rail siding when the accident occured.

Heavy rainfall in the area had caused the grain in the hopper to become wet and swollen, blocking the hopper and stopping the flow of wheat.

The worker had entered the silo and stood on top of the grain to clear the blockage with a steel bar.

However the grain elevator was still running during the operation and as soon as the blockage was freed, gravity caused the grain to head towards the hopper, quickly entrapping the man.

Justice Patricia Staunton noted that Graincorp had subsequently put in place remedial steps to remove the risk.

Neverthless, there was a need for specific deterrence in ensuring that training was received, understood and re-emphasised, she said.

Graincorp's operations company was fined $135,000 under the Occupational Health and Safety Act.

The action against Graincorp was brought by WorkCover who said the accident highlighted the "inherently dangerous" nature of grain loading.

"The risks of incidents such as these are easily identifiable and can be avoided," acting general manager Rob Seljak said.

"We cannot stress too strongly the need for appropriate risk assessment and safety training when working around silo operations."