Andrea Pezzi describes a novel approach to dewatering tailings.
Within the industry, miners are increasingly extracting massive amounts of ore as a result of improved technologies and declining mineral grades. After processing the target minerals, huge quantities of waste tailings are generated. In common practice, the tailings slurry is stored in a tailings management facility, also known as tailings ponds, where natural sedimentation occurs, and water is recovered for reuse.
Tailings ponds have an impact on the environment in the form of deforestation of a large land area and the risk of an embankment breach that, as seen on recent occasions, can result in grave consequences (the latest episode happened in South Africa on the 11th of September 2022 at the Jagersfontein diamond tailings dam). As such, increased selection guidance, conformity to evolving environmental standards and improved reclamation plans are being required for both new and existing mining operations.
To reduce risk, increase water recovery and minimise the impact of the disposal area, miners are increasingly considering dewatering the tailings. Dewatering tailings is best done with filter press technology, which can achieve high levels of water recovery, leaving the tailings approximately 85% dry – which then acts like a soil. For larger throughputs, it is necessary to optimise the number of filtration lines installed.
Diemme Filtration, which has vast experience in the field of solid-liquid separation with thousands of machines installed globally, has developed what it believes to be the largest filter press currently available. It joined the market on the 30th of November 2021 under the name of GHT.5000.F Domino. The first unit is currently being commissioned at a Copper Mine in Peru.
The daily capacity of a single filter press for dewatering mining tailings is around 10,000 tons/day of dry solids. This unit – with a plate size of 5 x 5m – is part of a major new tailings project, first in a pilot trial but later, assuming that is successful, as part of a much larger set of up to 9 or 10 of these presses for a total capacity of approximately 80,000t/d.
The GHT5000F means everything is optimised for state-of-the-art filtration with fast cycle times, and it is equipped with the necessary features to ensure a reliable operation, filtercloth cleaning, maintenance (easy access to the main components).
Bringing Automation To Filtration
The machine is also smart, with a high degree of automation. The unit is equipped with the Aida system tutor, which is designed to provide customers with real-time information on the statuses and performance of their filter presses via continuous monitoring, the data being accessible from a computer, smartphone or tablet. Aida processes data to provide valuable information for plant management decisions leading to improved control of the filtration process and operating costs; tracking and monitoring of the status of each filtercloth; values and trends of flows and utilities consumptions in the system, and status of equipment. Ultimately, it allows predictive and preventative maintenance to reduce downtime and plan more efficiently. Predefined KPIs can be set– including uptime, flowrates, power consumption, water recovery, production and cake moisture.
Andrea Pezzi is with Diemme Filtration