The Roy Hill project has been issued with a prohibition notice after another crane incident, this time involving a man cage.
SMH reported that on Tuesday last week a crane was used to lower a man cage, which “crashed” into scaffolding.
It is understood the cage was used to transport workers to and from heights.
A spokesperson for Roy Hill said that there were two workers inside the cage at the time, and that the collision was simply a "bump" against scaffolding.
Australian Mining understands that the focus of the investigation is on a radio communications fault experienced between the dogman on duty and the crane operator.
DMP state mining engineer Andrew Chaplyn said the incident occurred after a communication failure, which led the crane operator to lower the cage further than required.
"The department and Roy Hill are investigating the incident," he said.
"The aim is to identify the root causes so that the appropriate controls can be put in place to prevent a re-occurrence."
A spokesman for Roy Hill said no-one was injured in the incident, and that the prohibition notice would not affect first ore on ship as there was limited work which required work from man cages.
This is the 10th prohibition notice issued by the Department of Mines and Petroleum to Roy Hill, with a number of lifting related incidents having taken place on the construction site.
The project had already been issued with 11 improvement notices in the past financial year, and this year has attracted four improvement notices and a single prohibition notice.
Work was not stopped on the site, however crane operated man cages cannot be operated until a safe system of work has been verified.
Roy Hill came under scrutiny early this year after a series of serious incidents involving cranes, EWPs and other lifting devices.
In late January a crane tipped over during testing and commissioning procedures on the machine, and about two weeks later another accident occurred when supporting jacks failed beneath a construction module.
Less than a fortnight after that two men were severely injured during a lifting accident aboard a ship which was offloading materials at Port Hedland for the Roy Hill project, however this incident fell under the purview of the Australian Maritime Safety Authority and did not affect contractors Samsung C&T or Thiess.
At the time Roy Hill chief executive Barry Fitzgerald said there had been "serious issues" relating to safe lifting and crane operations, and that the situation was not acceptable and "a step change" in lifting operations was being sought.
However, Fitzgerald has recently been quoted as saying he was not concerned about the project’s safety performance.
"I think there is a difference between how much space we get in the media in terms of our safety performance and our actual performance, and we are actually quite pleased with what we have achieved," he said.
In other Roy Hill news the opening of the iron ore mine will be delayed until the second week of October due to bad weather and prohibition notices.
The mine was targeted for a September start, but will face delays according to an AFR report which quoted Hancock Prospecting executive director Tad Watroba.
It is understood the mine has stockpiled 13.5 million tonnes of iron ore ahead of the start date, which will provide cashflow while the project ramps up to the full capacity of 55 million tonnes per year, estimated to take a 30 month period.