Gina Rinehart's prospective iron ore miner, Roy Hill, has announced it is still on track for its 2015 completion after a poisonous kiwi fruit found at the remote construction site soured operations.
Police are still trying to solve the mystery of the strange fruit incident.
The case was reported to police on Monday and further details later revealed that cyanide was introduced into the piece of kiwi fruit at the site in Western Australia's Pilbara region.
Chem Centre, which operates a drug testing laboratory in Bentley, near Perth, was analysing the kiwi fruit and is working with police to help solve the mystery.
Police spokesman Inspector Dominic Wood said the Roy Hill worker, who took the fruit from the construction site's dining room before noticing it was unusual, has been cleared after health checks.
"This investigation includes whether this was a deliberate act, or accidental contamination during the production, transportation or distribution of the fruit," he said.
"The supply chain and production regions have been identified and are being consulted with."
Roy Hill Chief Executive Officer Barry Fitzgerald said in a statement that WA Police have confirmed this is an isolated incident of contamination.
"Our focus continues to be on the safety and well-being of our people," he said.
"The tightened food security measures we have implemented on site remain in place and we will implement further measures if deemed necessary or appropriate."
Roy Hill spokesman Bill Hart said the company's operations are continuing and the incident has not affected the planned completion date of construction.
Roy Hill plans to complete construction and deliver its first ore shipment by September 2015.
