McLanahan was able to offer a needed solution for managing gold leach tailings for one of Australia's oldest and now most profitable gold operations that recently embarked on a series of innovative process upgrades. The Victorian operation engaged processing consultancy firm Mincore to help with the project.
“Mincore and McLanahan have worked on a number of project studies previously. Having local engineering capability and support on both sides made the engagement much more efficient in being able to review process data and confirm the specific thickener operation and construction requirements,” said Richard Williams, McLanahan global product manager.
“We felt that a local manufacture and relatively low overall delivered cost solution would be best fit for the client," said Mr Williams. “Modular design provides the flexibility to manufacture in more locations and provides more certainty around time-sensitive projects.”
Due to the nature of the processing plant, Mincore specified material and design aspects to account for the highly acidic and corrosive process streams. A specific sealant was procured for the thickener flanges to perform at the correct duty, as well as stringent paint quality assurance including DFT, WFT, pinhole and holiday testing specified by Mincore to confirm coating integrity.
The thickener was designed in-house at McLanahan's New South Wales, Australia, location and included several process instruments, including bed pressure, bed level, rake torque and overflow clarity. The tank, support structures and bridge were all manufactured locally for a faster delivery time, taking only 14 weeks for final delivery to the customer's site.
Mincore’s site team was able to support installation by using four experienced technicians and one small mobile crane to place the thickener onto a pre-prepared concrete-bunded hardstand. The modular nature of the tank and bridge allowed for safe, fast and efficient site installation.
Dry commissioning includes checking for correct tank assembly, along with the installation and application of protective treatments. During this time, the drive and instrumentation are wired, and the mechanism is checked for correct alignment.
Once successfully completed, a wet commissioning will be conducted, where the feed to the Thickener is introduced and the process outcomes are evaluated for consistency. The process will ensure that the instrumentation is operating correctly, and that the data received and process outcomes meet the design requirements and overall client specifications.
McLanahan considers the full machine life cycle in all of their designs utilising a “Design for Customer” approach. For this thickener, that process included minimising the number of different fastener sizes and increasing assembly speed by minimising tooling and guesswork on site. Additionally, McLanahan designed in the following aspects:
• Integrated lifting attachment points preventing damage to paint and eliminating the need for the customer to source specialised lifting equipment
• A completely match-marked assembly system using large weld metal as marking to increase assembly speed
• Integrated electrical cable trays and conduits that reduce site work and damage to paint coating
• Local marshalling panel readout of all instruments complete with trending and status providing operator feedback in real time without needing to return to the control room
• Maximised space and clearance under the tank, facilitating pump and instrument access and maintenance
• Integrated product sampling points at multiple locations around the tank to confirm process outcomes