Dreamworld worker fired for 'almost identical' accident on the Thunder River Rapids ride

A Thunder River Rapids Ride operator was terminated from Dreamworld after two rafts collided on the conveyor almost two years before the disaster, an inquest has heard.

No one was injured in the November 2014 incident which saw the man fired almost two years before the terrifying tragedy which killed four people.

The inquest is examining the terrifying incident on October 25, 2016 when, after a pump stopped working on the Thunder River Rapids Ride, the water levels dropped and a raft got stuck on a conveyor, the Gold Coast Bulletin reports.

That boat was hit by a raft carrying Kate Goodchild, her daughter Ebony, 12, Luke Dorsett, Roozbeh Araghi, Cindy Low and her son, Kieran, 10. Their raft flipped and two adults were trapped while the other two adults fell out.

Barrister Steven Whybrow, acting for the families of Goodchild and Dorsett, this morning read from the employee's termination letter.

The letter said after a pump shut down on the ride, "a raft containing guests has bottomed out at the top of the conveyor due to water supply".

The Thunder River Rapids Ride at Dreamworld Gold Coast.

"An additional raft containing guests has then collided with it and continued to be pushed by the conveyor until it was shut down," Whybrow read from the letter.

Ride operator Chloe Brix, who has worked on the Thunder River Rapids Ride since 2013, said operators were never told about the incident or debriefed on safety procedures following the 2014 incident.

Brix said she only found out about the other employee's termination through gossip.

'Rides can break down 20 times a day'

Dreamworld's rides could break down as many as 20 times a day, the inquest has heard.

Engineer Matthew Robertson said that on busy days, he could be called to as many as 20 "Code sixes" (breakdowns).

He said on quieter days, there could be "virtually zero" breakdowns.

Robertson was called twice to Code 6 alerts on the Thunder River Rapids ride in the hours leading up to the tragedy.

'Ridiculous' situation: Staff not allowed to close ride

A problem pump on Dreamworld's Thunder River Rapids ride failed twice in 79 minutes in the hours before the tragedy, the inquest has been told.

It failed again only an hour after the second breakdown, with fatal consequences.

But the inquest heard Dreamworld's protocols dictated that the ride could only be shut down for the day after three breakdowns.

Rescue personnel stand by the Thunder River Rapids ride at Dreamworld on the Gold Coast, Australia. Photo / AP

The ride's south pump broke down at 11.50am and again at 1.09pm on the day of the tragedy, October 25, 2016.

The pump was re-set and the ride evacuated, the inquest heard.

After the second breakdown, ride operator Sarah Cotter told Robertson the situation was "ridiculous" and questioned what could be done about the problem pump.

Robertson told her that the ride would be shut down "if it happens again", the inquest was told.

Electrician did not attend second failure of south pump

An electrician did not attend the second failure of the south pump on the day of the Thunder River Rapids Ride disaster, the Dreamworld inquest has heard.

Robertson has told the inquest it was the usual practice for a mechanic and electrician to be rostered on each day as park technicians.

One the day of the disaster, which killed four people when a water pump failed just after 2pm on October 25, 2016, two mechanics had been rostered on to attend any breakdowns that day.

The disaster occurred after the south pump failed for the third time that day.

Robertson said when the first breakdown occurred at 11.50am the mechanics called in help from an electrician who then showed them how to fix the pump.

Clockwise from top left: Roozi Araghi, Luke Dorsett, Cindy Low and Kate Goodchild were killed on the Dreamworld ride.

"They [electricians] were distracted, there were other issues electrically in other aspects of the park," he said.

"I thought that if we knew and were allowed to reset them it would speed the process up."

When the pump failed again at 1.09pm, Robertson went to the ride with a fellow mechanic.

Robertson said he remained at the Thunder River Rapids Ride control panel when the other mechanic went to another part of the ride.

"I'm not 100 per cent if it was communicated to me before or after [that he] attended the [pump] drive room," he said.

"He returned and said he had reset the pumps."

Robertson said the south pump then started and the pair signed off the maintenance log.

He said he was asked by Cotter about what they were going to do about the pump dropping out.

Robertson told the inquest he told her it was their policy to shut the ride down for the day if the same fault happened for a third time.

He said he had been told that policy a week or two earlier.