TT402 Will Soon Resume Operations
22 March 2019
Thickener Bridge is the Latest Battle in the War Against Rust
Producing gold and copper in Papua, Indonesia has its own challenges. Replacing a 35-ton steel bridge that runs across the top of the TT 402 Concentrate thickener was a unique challenge to the staff at PTFI.
The replacement of the 100-foot steel bridge truss required a high level of precision and planning. The tight confines of the working area, and the corroded state of the structure added to the complications of the job.
“Our engineering team observed and verified the corrosion as ‘Severe’, so we quickly ordered the materials needed to start this project,” said John Wilmot, Vice President-Concentrating.
Rust has corroded the 30-year-old bridge to where the thickness in parts of its frame have been reduced by up to 30 percent.
Nothing is ever simple at PTFI
The bridge is a critical component of the thickener tank. “The bridge supports the total weight of the drive mechanism that runs the thickener, and it’s also an access way for employees to inspect and maintain the equipment,” said Adi Widyatmoko, Superintendent, Quality Control-Concentrating Engineering.
The project, began in December and scheduled to be completed in April, provided a significant challenge to the engineering team, said Kevin Sipayung, Civil Engineer.
“It was too narrow a work area, so we basically divided the bridge into eight segments based on the crane limitations,” Kevin said. “It’s a good illustration that when you engineer a project like this, you don’t just plan the project. Your engineering team also must ensure that the construction process goes according to that plan.”
The Right Time
Although the TT 402 is unavailable for use during the project, replacing the bridge has little impact on production.
“This is the right time to execute this job since we are at a low point in production throughput,” Wilmot said. “By 2022, when production starts to ramp up, all of our thickener tanks must be available for use.”
Rust is unavoidable aspect of life in Indonesia and copper mining, and its destruction cannot be neglected, Adi Widyatmoko said.
“In this case, the severe corrosion could have caused the bridge to fail and halt the production, but even more importantly, it would have been unsafe for an employee working on that bridge,” he said.
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