FLOTATION TECHNOLOGY
paving the way for broader adoption of HydroFloat CPF in base and precious metals processing. Eriez, BHP and its partners will continue to refine the technology and CPF flowsheets, share insights, and evaluate opportunities to expand HydroFloat applications across other operations.
CiDRA P29 interest and alignment gathers pace to the next generation flow sheet
CiDRA Minerals Processing’ s innovative P29 system has the potential to form the heart of future mineral processing flowsheets. Unlike other options that take effect further downstream, grind-circuit roughing with P29 offers the possibility of increasing grind size and directly reducing the recirculating load in grinding mills, increasing mill throughput by 20 % or more at a constant grind size.
More and more big mining houses are seeing its potential in existing plants to free up capacity and throughput. And in addition to brownfield, its potential is also being looked at in coarse recovery in greenfield flowsheets, with traditional grinding replaced by other technologies like vertical mills and high-pressure grinding rolls, leading to even greater near term value of a P29 grind circuit rougher.
With so much potential, and the urgent need for solutions to be made viable, CiDRA has partnered with Worley and Weir and formed an integrated collaborative team for the P29 technology development and implementation. Worley brings full EPC delivery capabilities, including technology development and commercialisation, and Weir provides experience in flowsheet and product development, as well as access to their market leading solutions including pumps, HPGRs and cyclones. The integrated team working on P29 solutions is advancing this innovative technology to a market ready solution for our industry. Worley has been working alongside CiDRA for four years, and in May 2025, CiDRA and Weir announced that they had signed a global collaboration agreement alongside a strategic investment by Weir in CiDRA’ s mining business.
IM spoke to Mark Holdsworth, CiDRA COO on where the heart of the value of P29 lies:“ If you are pulling out this-1 mm material, using the Bond power equation it is already a 60 % drop in specific energy per tonne. You then use that energy to increase your througput rate or reduce your grind size – and that’ s in a brownfield mine. But if you think about those energy savings, that can then lead you to greenfield mine future flowsheets with VRMs and HPGRs in place of tumbling mills. The other thing we are now having discussions about is coarse tailings. At 1 mm your water recovery in tailings goes from about 25 % recovery up to 70 %+ recovery, plus it means a far more stable stacked tailings. This then is unlocking additional value from an ESG perspective in terms of social licence to operate.”
Any P29 introduction commercially would certainly be timely as the world needs more minerals to deliver the technology to electrify the world to reach net zero. It takes time to develop new mines and that is not fast enough to meet global demand. Deposits themselves are becoming more difficult to commercialise – they are becoming more remote, often in arid areas with water scarcity and with a lack of existing infrastructure
Many mining groups are now looking at ways to lock coarse recovery in combination with technologies like roller milling and dry processing because it means significant power and water savings, which means an improved licence to operate. Lack of fines and slurry also means greater tailings disposal safety and stability.
Holdsworth adds:“ Going from a typical p80 of 100-200 µ m to p80 of 600-800 µ m is a reduction of 50 to 60 % in comminution energy. What if we can reject 70-80 % of the feed mass at this size? Rejecting feed at this size also increases water recovery. A P80 of 600-800 µ m also unlocks VRMs and HPGRs as comminution methods, replacing SAG and ball milling. Depending on the ore, this can also mean improvement in breakage at mineral boundaries to improve recovery and quality. CiDRA’ s P29 technology continues to show good coarse mass rejection with high metal recoveries out to P80’ s of 1,000 µ m, plus it works well in hyper saline water. The P29 flowsheet also vastly reduces or removes any rougher flotation requirement – with 80 % mass rejection. P29 concentrate can then be reground to conventional flotation cleaning.”
He adds:“ Weir is working with us and supporting us across the board, from pump design, to dewatering design, comminution equipment modelling and modelling of the cubes.”
Where did P29 come from? CiDRA started out looking for an alternative to conventional flotation and came up with the use of an open cell polyurethane foam media as a substrate. An engineered hydrophobic coating is applied to the substrate enabling it to attract hydrophobic particles. The substrate foam is in the form of small cubes which is mixed with the ore slurry in a rotating drum. The slurry penetrates around and through the foam and contacts the foam surface and the reagent chemical, the same that is used in flotation, attracts the hydrophobic particles.
Pilot plant trial recovery results from BHP Carrapateena
International Mining | OCTOBER 2025