A West Cost mining company has been left devastated after hundreds of thousands of dollars of damage was done to heavy machinery.
The manager of the gold mining company, who requested the business remain anonymous, said he arrived at the site on Tuesday afternoon to find the gate lock had been cut and "all the gear was smashed up".
He said the keys to the vehicles were kept at an on-site office, and were stolen when the offender/s smashed through a window.
"They then jumped in a digger and used it to smash the other vehicles.
"There were three big trucks - 20-tonne trucks - a fuel tanker, a loader, and two or three diggers smashed," he said.
Images show a loader pushed on its side, a truck and trailer also pushed over with its cab smashed up and contents tipped out, a fuel truck with a smashed in roof, and a digger with its door and panels smashed in.
The manager said insurance investigators were yet to assess the damage, but he picked it to be around $500,000-$700,000.
"To replace them will probably cost over $1 million, but it depends on the insurance analyser."
He said he "felt awful" on discovering the damage.
"It's horrible because we need to mine to get all our costs covered, and I am not sure if insurance will cover the lost income," he said.
The manager said the offender/s also stole a digger battery and a couple of tools.
He said police had been to take finger prints and were conducting an investigation.
"They will let me know once there is any information."
He said a similar incident had happened in June at a nearby mine, so he was questioning whether the incidents were related.
"The people who damaged the machinery must be a really good digger operator because they was not much mud on the ground, it was very clean," he said.
"They knew what they were doing, so I don't think it was young people."
Earlier in the year, there was also a break in on the site where the offender/s stole roughly 100-200 grams of gold, valued at about $7000, he said.
Police confirmed they had received a report and are currently conducting enquiries to gather more information.
• If anyone has seen anything or has any information, please call your local police station or Crimestoppers anonymously on 0800 555 111.