Abstract

As the worldwide demand for copper rises to facilitate the shift from carbon-based to renewable energy systems, mining companies are exploring innovative methods to boost mill throughput, enhance recovery efficiency, maximize water recovery, create safer tailings disposal facilities and reduce carbon footprint for both new and existing copper resources.  One new technology that can achieve all of these is Coarse Particle Flotation (CPF).  The universal adoption of CPF depends on strong collaborations between original equipment manufacturers (OEMs), engineering companies and mine owners who will ultimately endorse and sponsor this innovation.  As these collaborations move forward, an ecosystem of CPF complementary technologies are emerging, for example Anglo American’s hydraulic dry stacking (HDS) technology for creating more stable geotechnical impoundments and recovering water.

To overcome the particle size limitation of conventional flotation, OEMs are working hard to develop CPF machines which are at various stages of maturity and implementation. Eriez developed the first commercial machine over twenty years ago, the HydroFloat® which employs a fluidized bed for the specific purpose of floating coarse particles containing small amounts of exposed, hydrophobic valuable mineral.  Alongside the machine design, conventional copper flotation flowsheets are being adapted to achieve the main benefits of CPF.  Considerable optimization has already occurred, for example the selection of cyclones versus teeter-bed separators to prepare HydroFloat feed, which was evaluated in a side by side comparison by Newcrest (now Newmont) at their Cadia Valley operation and reported at MillOps 2024.  

Another innovation is to simplify the CPF flowsheet by increasing the capacity of the major unit operations.  In this present work, an hypothetical conventional copper flotation flowsheet consisting of a 130k tonne per day throughput and employing CPF in a tailings scavenging (TS) application with cyclone feed preparation will be used as a benchmark to consider opportunities for improving project and operating costs by increasing the HydroFloat unit size thereby reducing the number of machines installed.  This analysis will include equipment selection, layout, and design in order to evaluate comparative capital and operating cost estimates.  The authors will suggest the optimum HydroFloat size based on plant throughput and the key criteria for HydroFloat size selection in large copper projects.

It is expected that in the majority of cases that the simplification of the flowsheet with reduced numbers of machines will have a significant impact on project costs, which in turn will improve the business case for CPF projects.  This will allow CPF to play a larger role in the industry and that many of the benefits outlined including tailing impoundments and dams that take advantage of the fine and coarse product of CPF flowsheets will be possible. The integration of CPF into tailings management strategies allows for the development of more effective and environmentally friendly solutions, potentially leading to the reprocessing of tailings in the future.