Mine Backfill
We are leaders in the design, execution, and ongoing management support of backfill systems.
Since 1991, our engineers have solved some of the most complex backfill challenges while testing and designing hydraulic, paste and cemented rock fill projects across the world. We pioneered the development of full flow technology to keep backfill reticulation systems fully pressurised to manage energy and reduce pipeline wear. Our in-house laboratories provide advanced testing capabilities, enabling us to maintain full control over sample integrity and data quality.
Our global backfill group brings together engineers, operators, technologists, and specialists from across our offices worldwide. This integrated approach ensures we deliver coordinated expertise and resources to clients, wherever their operations are located. The team focuses on the design, implementation, and operation of backfill systems. Our expertise covers mining and process engineering, hydraulics, pipe wear analysis, cement chemistry, and mechanical engineering, including pipe stress and transient analysis. We support projects from early-stage concept development through to commissioning, providing expertise across the full system from surface mill discharge to underground barricade placement.
NOTABLE PROJECTS
Mine Backfill Projects from around the world
We conducted engineering studies and test work, and completed the detailed design and commissioning of the paste plant and underground distribution system. The design incorporated dual pressure filters, a paste conditioner to repulp the tailings, and options for both gravity and pumped flow underground.
After completing a comprehensive backfill test campaign and developing a backfill strategy as part of the front-end engineering, we completed the detailed engineering for the backfill preparation plant and underground distribution system for the Kamoa underground mine. We also provided construction and commissioning assistance and developed the backfill management system, as well as providing classroom and practical training for the operators and local workforce.
We conducted an operational performance review and debottlenecking study that led to the detailed design of a capacity expansion from 120 m³/h to 180 m³/h.
Key plant improvements included cyclone underflow thickening, increased buffer capacity, mixing optimisation, and expansion of the electrical infrastructure. These changes enabled the plant to meet increased underground production demands.
After conducting a hydraulic assessment of the underground distribution system, we identified the need to install two underground choke stations in the existing paste backfill system. We designed the choke stations to allow pressurised upstream flow, which significantly reduced pipe wear rates.
We completed the detailed engineering and implementation of a 90 m³/h cemented aggregate fill plant for the AngloGold Ashanti Geita mine in Tanzania. The work included on-site test work to develop optimal mix recipes, as well as providing operator training and ongoing operational support.
Paterson & Cooke carried out detailed engineering, provided construction assistance, and commissioned the paste plant and underground reticulation system. This included the binder feed system with varying recipes and dosage rates. The plant design enables repulping of previously deposited tailings and the addition of aggregate for improved backfill strength performance. Pulsation dampening on the discharge pumping system alleviated potentially damaging transient events from the S-Tube style positive displacement pump necessitated by the aggregate addition.
After completing a basic engineering study that examined the application of paste backfill at the Outokumpu Kemi Chromite mine in Finland, and following extensive process and strength testing, our design included tailings dewatering via thickening and vacuum disk filtration, followed by continuous mixing. The binder comprised a blend of cement and locally sourced slag to achieve the required strength. Once mixed, the paste backfill was pumped or delivered underground by gravity, providing operational flexibility. The plant had a nominal capacity of 265 t/h (approximately 200 m³/h).
We carried out the feasibility and basic engineering of this unique paste system for backfill and underground tailings disposal. The design included accurate control of multiple paste recipes and significant redundancy in the process and equipment selection to maximise utilisation in-line with the processing plant.
After performing a pre-feasibility study, the detailed design for the expansion and upgrades to the existing paste backfill system was completed. The design included additional filtration capacity, improved mixing, and refurbished paste pumps. These improvements reduced capital costs while enhancing overall performance.
