Two autonomous trucks collided at a BHP iron ore mine in the Pilbara at the weekend in an accident blamed on wet weather.

BHP is investigating the accident, in which no one was hurt.

The mining giant said the collision between the driverless vehicles happened about 11pm on Saturday at the Jimblebar mine site, about 40km east of Newman.

A company spokeswoman said it followed “significant rainfall that deteriorated the road surface, causing one vehicle to slip into the other”.

“Operations resumed in the hours after the incident and no one was injured,” she said.

It’s understood that the one of the trucks was travelling about 27km/h and the other at 14km/h.

Radio station 6PR reported that one of the trucks was loaded and the other empty.

Jimblebar was the first mine in BHP’s Pilbara iron ore portfolio to move completely to driverless trucks. The mine had a fleet of about 50 autonomous trucks by the end of 2017.

The company said at the time that autonomous haulage had helped reduce costs by 20 per cent and shielded employees from dangerous situations.

Last month two driverless trucks collided at Fortescue Metals Group’s Christmas Creek iron ore mine.

In that case, one truck reversed into the other, which was stationary, following a wi-fi outage.

It was believed a remote operations error caused the accident when wi-fi was restored.

Fortescue said the incident was not a failure of its autonomous haulage system.

BHP’s accident follows the release last week of a report into its runaway ore train crash, which caused losses of about $300 million.

In November, BHP deliberately derailed the train in the Pilbara after it had taken off without its driver when an emergency brake turned itself off.

The Australian Transport Safety Bureau report said that a maintenance crew sent to help the driver went to the wrong train.

The 268-car train travelled for 91km at up to 161km/h before being derailed remotely.