Copper Extraction Cribs at Rio Tinto Bundoora, Melbourne

• Client: Rio Tinto Bundoora, Melbourne
• Project: Copper Extraction Cribs
• Product: Polyurea, Polyeuro 5502
• Completion: 2012 – 2013

On-site requirements

• Provide tank coatings on Melbourne site for long-term protection of each shell piece that makes a full crib vessel.
• Provide a seamless hard wearing coating capable of withstanding humid conditions at around 55 degrees.
• Provide a coating able to stand up to large ore with sharp edges with potential 100 tons of pressure.

These cribs were being designed for testing the extraction of copper from iron ore using microorganisms. Each shell had a water jacket to help keep the temperature at 55 degrees where the bugs would thrive and eat the iron ore. As they ate they remained at a happy temp of around 55 degrees. Over a period of two years the theory was there would be little ore and lots of copper.

Rio Tinto contracted Polyspray to coat each shell of the cribs with polyurea to prevent corrosion. A full seamless resilient coating was required to stand up to the sharp ore and each crib was filled with 100 ton. Penetration of the coating would result in fast-acting corrosion potentially causing failure to the project.

Each shell was garnet blasted to 95um plus, primed with a two-pack epoxy on the exterior and coated with polyurethane foam also externally to provide a thermal barrier for the water jacket. Then a full seamless membrane of polyurea was applied internally at approximately 4mm thick. Each shell was then transported to Bundoora, Melbourne, for assembly of the cribs.

In conjunction with other specialised contractors Polyspray had all shell sections of the cribs coated and delivered on time for assembly.