Tag Archives: dewatering

Sedgman books tailings dewatering work at QCoal’s Byerwen coal mine

CIMIC Group’s minerals processing company, Sedgman, has been awarded a contract to design and construct a tailings dewatering facility at QCoal’s Byerwen coal mine in central Queensland, Australia.

The project will result in a lower operational risk profile, less power usage, and improved water recovery and management of dewatering chemicals, Sedgman says.

Sedgman Managing Director, Grant Fraser, said: “We are pleased to continue working with QCoal with a key focus on reducing impacts and undertaking environmentally responsible practices. The tailings dewatering contract at Byerwen is a great opportunity to achieve joint goals in ESG, an important focus for the industry.”

Construction work for the Byerwen mine will commence this month and the project will conclude in mid-2022.

Back in October, Sedgman was awarded two contract extensions by QCoal to continue to operate and maintain its Sonoma and Byerwen mines processing plants in Queensland.

ABEL pumped up by IndustriTech partnership in Australia

ABEL has announced a distribution partnership with IndustriTech Pty Ltd for the Australia mining market.

IndustriTech provides service-oriented solutions in three areas: technical advice, reliability and repair services and distribution services. Together with ABEL’s wide range of positive displacement pumps, it will provide complete customised product and service solutions for high solids concentrations and efficient dewatering processes. Typical applications are dewatering, tailings, solid transfer and thickener underflow.

For over 70 years, ABEL has specialised in pumps for filter press feeding and filter cloth cleaning. Both ABEL’s piston diaphragm and high-pressure plunger pump provide tailor-made features to ensure a short, efficient and energy saving filter press process for the customer, according to the company. This performance can be seen in the high level of dryness of the filter cake, resulting in increased daily metal extraction and profitability for the customer.

Weir Minerals continues to go with the Multiflo in barge applications

Even with 40 years of custom barge solution expertise under its belt, Weir Minerals says it is continuing to innovate with new designs for applications in oil sands, tailings management and tropical and cold climates.

Developed over the decades, the Weir Minerals range of Multiflo® barges provides a solution for numerous applications, according to the company.

Water reclamation for oil sands market

Reclaim water barges are an integral part of tailings management solutions in oil sands applications, where tailings contain high percentages of water that can be recycled back through the process plant.

Upon identifying the need for reliable systems which were easy to manage and maintain, Weir Minerals developed its mega-barge exclusively for the oil sands market. This all in one package includes pumps, valves, hoses, and piping.

“This is where our turnkey value proposition really took off,” Kris Kielar, Product Manager for engineered-to-order dewatering products at Weir Minerals Canada, explains. “Our largest barge system includes a fully integrated electrical control houses that powers 9,000 hp (6,711 kW) worth of pumps, overhead cranes, remote monitoring and control, and the longest floated walkway we’ve ever provided, with ‘warm-up’ stations every 150 m for one kilometre.”

Mega-barges are the ideal solution for unique applications, such as the scale of water reclaim needed at some of the world’s largest oil sands operations, according to Weir Minerals.

“A typical oil sands operation requires nine barrels of water per barrel of bitumen produced,” continues Kielar, “so the more water that can be reclaimed, the better. The larger the operation, the bigger the water saving potential.”

In addition to the mega-barges for the oil sands market, Weir Minerals also developed modular barge packages as a fully customisable solution for ease of shipment, and a reduction in both capital costs and onsite installation costs. The introduction of both static and mobile, land-based, booster stations and pumphouses further expands the Multiflo barge solution capability while maintaining a single point of contact for customers, the company says.

Tailings management

The need for custom barge solutions for tailings management has increased in recent years. Where previously dewatering pumps in tailings applications were “set-and-forget”, the increased focus on tailings dam safety has shined a new spotlight on barge solutions that can provide heavy-duty, reliable pumping, Weir Minerals said.

Not only must sites revisit current arrangements to consider how their tailings will be handled in the future, they also need to empty the old dams decommissioned by environmental and mining authorities, the company said.

Ricardo Menezes, Barge Systems Specialist at Weir Minerals Brazil, said: “We are equipped to provide the entire solution. From initial consultation and design, to manufacturing, commission, and training and supervision of site operators. We work hard to bring our customers the best possible solution for their site, and we do it all under one roof.”

These all-in-one Multiflo packages eliminate the headache of integrating civil construction, electrical control rooms, control systems, pipes, cables, and mechanical and electrical works, according to the company. Weir Minerals engineer these dewatering barges in-house and employ naval engineering consultants to create tailored solutions for its customers.

Menezes continues: “Sites are being asked to transport tailings on a larger scale than before. An off-the-shelf solution might not work with their existing site infrastructure and that is where our fluid transport expertise comes in.”

Reliability in any situation

Applications in tropical environments, which experience heavy and sometimes unexpected rainfall, often require barge-mounted dewatering pumps to handle the rapidly rising water levels.

Multiflo land-based barges are built to float, protecting the pump unit from being flooded as often happens with a traditional skid pump unit, Weir Minerals says.

These land-based barges are fitted with integrated skid runners that allow them to be towed around mine sites and launched or retrieved with the use of dozers or excavators. The integrated skid runners also provide the added benefit of using the barge as a skid pump operating at the pond edge with easy land access for operators and servicing, the company says.

Marnus Koorts, Product Manager for dewatering pumps at Weir Minerals South Africa, says the company gets very specific requests for these land-based barges.

“We recently completed a project for a customer experiencing regular high wind speeds and tropical storms,” he said. “We needed to account for wave action and wind loading to ensure our solution would minimise risk of structural damage during these storms.”

Other considerations such as water quality, where pH can range from very low through to high, and water content, such as high percentages of suspended solids and floating debris, are also key to maintaining dewatering equipment on site, according to the company.

“Multiflo barges maximise reliability through innovative protection systems chosen specifically for the environment that the barge will operate in,” Weir Minerals says.

For one customer in South Africa, the Weir Minerals team needed to account for more than just water, according to Koorts.

“One of the design requirements for this particular installation was for the handrails and other structures to be engineered to prevent crocodiles from gaining access to the deck space.”

Dewatering in cold climates

In the last year, Weir Minerals barge specialists from Canada have been working with teams in Russia and Finland, to establish a European centre of expertise specifically for dewatering barges in cold-climate applications. Key environmental factors such as wind, snow and seismic loading can affect the buoyancy and stability of the barges, which they looked to address.

“We’re building on the work of the North and South American teams,” Artem Filippov, Dewatering Product Manager at Weir Minerals Russia, said. “Working together and using insights gained from their years of experience have allowed us to create unique barge dewatering systems for our European customers.”

Weir Minerals’ cold-climate expertise comes from experience in floating barge systems at temperatures below -45°C, de-icing systems and winter barge access systems. In addition, Multiflo barge systems are fully marine naval certified under all weather conditions and are marine architect certified, the company says.

Babylon expands equipment and service offering to BHP Nickel West

Babylon Pump & Power says it has secured a new power generation and dewatering contract with BHP’s Nickel West division, in Western Australia.

The ASX-listed company has provided dewatering services for BHP since October 2018 and this contract expands on the equipment and services to be provided while securing the existing business for a further three‐year term – from February 1, 2020 to January 31, 2023 – it said.

Last year, Babylon Pump & Power established a rental service base on the East Coast of Australia with the completion of its acquisition of Primepower Queensland. This made it one of the largest independent and diversified engine re-builders in Australia, it said.

Tenova TAKRAF proves dry stack tailings credentials at Uzbekistan gold mine

Tenova TAKRAF says it recently installed three DELKOR overhead filter presses at a gold mine’s processing plant in Uzbekistan as part of its wider tailings dewatering system.

The system comprises three DELKOR overhead filter presses each processing around 120 m3/h of gold tailings. Each machine contains 177 mixed membrane filter plates with a size of 2 m x 2 m, and includes a high-pressure cloth washing system.

These filter presses form an important part of Tenova TAKRAF’s complete Dry Stack Tailings (DST) technologies solution, which covers processes from sedimentation to filtration and material handling, the company said.

The supply also included several pieces of ancillary equipment, including belt conveyors for cakes discharged from the filter press (each machine is equipped with a cake breaker), pumping skids for membrane inflation, filter cake washing pumps and high-pressure cloth washing pumps.

“The entire scope of supply, including the slurry feed pumps, is fully controlled and managed by state-of-the-art software,” the company said.

It added: “The complexity of the dewatering process required by this project clearly highlights DELKOR’s filter press potential across the dewatering spectrum. In fact, the filter press cycle includes filter cake squeezing, filter cake washing and filter cake air blowing, with the filter cakes washed with process water in order to remove unwanted residual cyanides from the dewatered cakes.

“Importantly, the required residual moisture content within the dewatered cakes was achieved immediately during start-up.”

Marco Zeni, Tenova DELKOR Project Manager, said: “Notwithstanding demanding site conditions, installation and commissioning, together with the required operational training, was successfully completed. With this project, we take another important step towards firmly establishing DELKOR also as a provider of filter presses to round up the filtration product portfolio and once again demonstrating that: it pays to talk to a specialist.”

Integrated Pump Rental keeps its head during Lesotho mine dewatering project

Integrated Pump Rental says the quick deployment of its dewatering solution has allowed a Lesotho mine to keep operating as normal.

A constant flow of water into the mine’s pit area demanded water be urgently and reliably pumped out, according to the company. A fuel-efficient Sykes Xtra High Head pump set was chosen for the job, pumping into a 200 mm HDPE line with a head of 127 m to a holding dam.

According to Integrated Pump Rental’s Andre Strydom, timing was of the essence to the customer: “We secured this dewatering contract due to our quick and effective response. The Sykes XH150 unit was on site and commissioned just 24 hours after receiving the call from the customer.”

Strydom highlighted that, as mines and quarries go deeper, conditions require a solution like the Sykes XH150. With its automatic priming and solids handling capacity, it is designed to dewater more efficiently and effectively.

“The unit has one of the best shaft stiffness ratios of any automatic priming pump on the market,” he says. “Sykes engineers have ensured that the enormous pressures and heads associated with such performance do not compromise seal integrity through shaft flexing.”

All models have the ability to operate unattended at high discharge heads, with the pumps able to be primed with long suction hoses and the ability to manage suction lifts of up to 9 m.

“The units can even run dry for extended periods due to the oil bath mechanical seal assembly,” the company said. “Designed for robust and reliable performance with high volumes of water, Sykes pumps have an established reputation for the fast and effective control and removal of sub-surface water.”

The pumps can even operate in “snore” condition, Integrated Pump Rental says, which accommodates fluctuating suction levels. “In these conditions, the pump will snore until the liquid is available for the pump to fully re-prime itself automatically,” the company added.

Weir Minerals’s Essack on end-to-end tailings and pipeline solutions

As mining companies’ tailings facilities continue to be scrutinised by regulators and non-governmental organisations, Weir Minerals Africa Process Manager, Hoosen Essack, has talked up the need for tailored tailings solutions for the future.

Combined with the stringent accountability that mine operators have to local communities, tailings management is now a significant consideration, with processing requirements and technology changing rapidly. Traditionally involved in the pumping of tailings, at Weir Minerals we have extended our expertise into this area to encompass the entire tailings process. From dewatering to transport, disposal, and the conversion of tailings into a resource, we can provide customers with an end-to-end tailings and pipeline solution.

This holistic, solutions-based approach to tailings management strengthens our relationship with customers and adds value to their operation beyond pumping. In light of water conservation, operational sustainability and safe deposition of tailings, it’s important that we invest in this area to help solve crucial issues within the mining sector.

Our extension into the tailings processing field means we are now involved in the production of the material, as opposed to simply transporting it. Through extensive consultation, site visits and audits, our team ascertains the customer’s objectives and recommends a complete, optimal solution to meet their needs, which can include dewatering equipment, piping, pumps, valves and instrumentation.

This seamless approach is a departure from the traditional industry practice of sourcing components from multiple suppliers, which are challenging to integrate. Our extensive research and development capabilities means we can provide a wide spectrum of tailings management options not limited by a particular type of technology or equipment.

This involves assessing the variations in capital and operating expenditure along with the overall and long-term benefits of each, providing a truly customised solution. Prior to implementation, rigorous testing and trials are conducted to assess viability and performance ahead of final selection, detailed design and engineering, delivery and commissioning. Another key benefit to customers is the ability to transform tailings into products, which can safely be used by the mine, such as road construction material. This involves dewatering of tailings, in which we have extensive expertise.

Dewatering involves removing liquid from waste slurry so that the remaining solids can be deposited in a tailings storage facility or returned to the site from which it was mined as backfill. There are several dewatering methods to render waste slurry to differing degrees of dryness, ready for transport from the plant to the deposition site. Any liquid recovered through dewatering is returned for reuse in the process.

We can provide a variety of processing systems inclusive of equipment and infrastructure to achieve the final tailings product that is required by the customer, from thickening to create a paste, or applying a filter to produce a product which can be dry deposited. As tailings management evolves, the industry is moving towards the latter for increased safety and stability, and in the process maximising water recovery.

As mine operators become more vigilant in managing their tailings, new processing technology is continually developed, including at the Weir Technical Centre in Australia. Innovative, uniquely tailored solutions incorporating high performance equipment and a global service footprint means we are leading the industry in making tailings more sustainable. Ideally, this will lead to a future where tailings related hazards are a thing of the past.

Metso launches VPX filter as part of new tailings management approach

Metso says its new approach to tailings management is aimed at addressing the water conservation and responsible mine reclamation requirements that are becoming increasingly important for mines to ensure they can retain their social license to operate.

Its new approach is spearheaded by the launch of the new Metso VPX™ filter for tailings dewatering, which, with an operating pressure of up to 25 bars, can deal with difficult-to-dewater tailings.

The company’s broader tailings management concept is geared towards enabling and supporting environmentally and economically sustainable mining, it said.

Victor Tapia, President, Mining Equipment business area at Metso, said: “Our ambition is to challenge the conventional way of looking at tailings management in mining.

“In practice, this means that besides environmental and regulatory concerns related to tailings, we need to improve the conservation of water, chemicals and ore, as well as looking for opportunities to reprocess tailings and generate value by extracting any remaining minerals. Ultimately, it allows transforming legacy practices in tailings management into a new, positive value creation model.”

Metso is driving this change by introducing a new concept for the dewatering, handling and reprocessing of tailings. It said: “Designed to maximise water recovery and reduce the footprint of tailings dams or eliminate them completely, Metso Tailings Management Solutions provide a long-term solution for mining companies looking for a viable approach to their tailings management and end-of-mine strategies.”

There are a huge amount of tailings discharged and lying in legacy dams, according to Metso. “Today, only about 5% of tailings are dewatered, while roughly 70% of the mines are located in countries where water scarcity is considered as an issue. The way tailings are handled can have a long-term impact on the mines’ economic efficiency as well as on the well-being of the surrounding environment and communities,” the company said.

Niclas Hällevall, VP of Beneficiation Solutions, Mining Equipment business area, said: “Metso views dry filtered tailings as the most viable and long-term solution for tailings management: it helps in recycling significantly more water to the concentrator, while enabling mines to reduce their freshwater footprint when compared to traditional tailings impoundments. Furthermore, the risk of tailings dam failure could be completely avoided by dewatering and dry stacking the tailings.”

He added: “Contrary to conventional belief, dry tailings are also much more capex (capital expenses) and opex (operating expenses) efficient compared to wet or thickened tailings.”

Metso Tailings Management Solutions bundle Metso’s beneficiation technologies into a “full, customisable and future-ready suite of solutions”, it says. Metso, with its core component, is taking filtration technology “to the next level” by introducing the Metso VPX filter, a new generation filtration solution for maximum water recovery and reuse, it said.

The company said: “The Metso VPX filter can handle difficult-to-dewater tailings, because it has up to 25 bars operating pressure, the highest pressure in its category. This enables up to 90% water recovery. The Metso VPX is also equipped with a fully electromechanical drive system and no hydraulics, making it the safest solution on the market. With its modular design, the Metso VPX filter is scalable as well as easily transportable to the site in standard containers.”

The VPX filter is available for mining customers globally and an ideal solution for a range of dewatering applications, Metso said, adding that the filter press will be on show at the Exposibram trade fair to be held in Brazil, in September.

Vale exploring dry stacking/magnetic separation to eradicate tailings dams

Vale has confirmed a Reuters news report from last week stating that it would spend an additional BRL11 billion ($2.5 billion) on dry iron ore processing over the next five years.

The company said it has invested nearly BRL66 billion installing and expanding the use of dry processing, using natural moisture, in iron ore production in its operations in Brazil over the last 10 years and it would carry on this trend.

“By not using water in the process, no tailings are generated and, therefore, there is no need for dams,” the company said, added that about 60% of Vale’s production today is dry, and the goal is to reach 70% in the next five years.

Dry processing is used in the mines of Carajás, Serra Leste and the S11D Eliezer Batista Complex (pictured), in Pará, Brazil, and in several plants in Minas Gerais. In Pará, in the Northern System, about 80%, of the almost 200 Mt produced in 2018 was through dry processing. The main Carajás plant, Plant 1, is in the process of conversion to natural moisture: of the 17 plant processing lines, 11 are already dry and the remaining six wet lines will be converted by 2022.

Serra Leste’s treatment plants, in Curionópolis, and S11D, in Canaã dos Carajás, also do not use water in ore treatment, according to Vale. In S11D, for example, the use dry processing, using natural humidity, reduces water consumption by 93% when compared to conventional iron ore production.

In Minas Gerais, dry processing increased from 20%, in 2016, to 32%, in 2018. Today, this type of processing is present in several units, such as Brucutu, Alegria, Fábrica Nova, Fazendão, Abóboras, Mutuca, Pica and Fábrica. “Over the following years, the objective is to roll it out at other locations in Minas Gerais, such as the Apolo and Capanema projects, which are currently under environmental licensing,” the company said.

Vale said: “Dry processing is linked to the quality of the iron ore extracted from mining. In Carajás, as the iron content is already high (above 64% Fe), the ore is only crushed and sieved, so it can be classified by size (granulometry).

“In Minas Gerais, the average content is 40% iron, contained in rocks known as itabirites. To increase the content, the ore is concentrated by means of wet processing (with water). The tailings, composed basically of silica, are deposited with water in the dams. The high-grade ore resulting from the process can then be transformed into pellets at the pelletising plants, increasing the added value of the product.”

The mills that operate dry processing in Minas Gerais depend on the availability of ore with higher levels – about 60% Fe – still found in some mines in the state. “In order to achieve the necessary quality, and be incorporated into Vale’s product portfolio, it is necessary to blend with Carajás ores, carried out at Vale’s distribution centres in China and Malaysia. The process allows Vale to offer excellent quality ore which can be tailored to meet the needs of our clients,” the company said.

The blending of the product with natural moisture does not eliminate the need for humid concentration of the low-grade itabirite used in the production of pellets. However, to reduce the use of dams, Vale plans to invest approximately BRL 1.5 billion on dry stacking technology in Minas Gerais between 2020 and 2023. This technique filters and reuses waste water and allows the latter to be stored in piles, thus reducing the use of dams. The goal is to achieve up to 70% of the waste disposed in the coming years, but success depends on the improvement of technology and external issues, such as environmental licences, Vale said.

“Today, Vale doesn’t have a dry stacking operation that can deal with the production quantity especially in a region with high rainfall indices, such as the Ferriferous four-side, in Minas Gerais. The available dry stacking technology is used on a small scale around the world – up to 10,000 t/d of tailings produced – in desert regions or with low rainfall. In Minas Gerais, Vale’s tailings production quantity is, on average, 50,000 t/d per unit,” Vale said. In 2011, the company developed a pilot project on the Cianita stack in Vargem Grande, after an investment of BRL100 million.

The studies were completed in 2018 and the technicians evaluated the geotechnical behaviour of piles under rainy conditions. The next tests will be applied on an industrial scale at the Pico mine in the municipality of Itabirito, Vale said.

“Another solution that has been studied is the dry magnetic concentration of iron ore based on the innovative technology developed by New Steel, a company acquired by Vale at the end of 2018 for BRL1.9 billion,” Vale said. “The dry magnetic concentration eliminates the use of water in the concentration process of the low-grade ore, which disposes the waste generated in sterile piles, similar to what happens in dry stacking. This technology, however, is in the industrial development stage and is not yet ready to be applied on a large scale.”

Outotec looks for consistent and efficient dewatering with new paste thickener

Outotec has introduced the 2nd Generation Paste Thickener to, it says, maximise underflow density regardless of challenging mineralogy and tailings feed-rate variation.

The thickener enables consistent and efficient dewatering performance – even with changing process conditions, according to the company.

“Through consistent performance and high underflow density, the 2nd Generation Outotec Paste Thickener maximises beaching angle in the tailings storage facility to provide safer operations and maximised lifespan,” Outotec said.

The new paste thickener provides ease of operation and reliability for applications requiring a high degree of dewatering, such as minerals tailings, mine backfill, and pre-leach and counter current decantation circuits, according to the company. “The technology is customised to address each operation’s unique drivers, which can include environmental concerns, water recovery, regulatory requirements, tailings management, or limitations on available land space,” the company said.

Outotec has a history of developing paste thickeners, as well as the design and delivery of large-scale paste thickening projects. “This has given us a deep understanding of the key aspects of high-density thickeners, including effective flocculation, dewatering, raking, prevention of rotating mud beds, process control, and the discharge of thickened solids,” it said.

“One such case was the deployment of Outotec paste thickener technology – including a full-scale paste tailings plant and Outotec ACT Thickener Optimizer system – at Yara’s Siilinjärvi apatite mine in Finland (pictured),” Simon Courtenay, Product Manager for the Outotec 2nd Generation Paste Thickener, said. “The plant generates around 10 Mt of tailings a year and, thanks to the Outotec ACT Thickener Optimizer, the paste thickeners can consistently run with a high and stable underflow solids content of 66-68%, regardless of challenging mineralogy and tailings feed-rate variation. This results in average beach slope angles of 3.5° (6.1%) in the tailings disposal area, helping to extend its lifespan. The system has also enabled a 10-20% reduction in flocculant costs.”

The new 2nd Generation Paste Thickener builds on this proven performance with a range of innovative new features, according to the company. For example, vertical load monitoring with the Smart Rake Lift system means the Outotec Paste Thickener is one of the only systems in the world that can detect early formation of rotating beds, enabling counteractions to be taken early, Outotec said.

The system also monitors and actively adjusts the individual hydraulic cylinders to maintain alignment of the rake mechanism. Incorporating vertical load sensing with plant process data in the Outotec ACT Thickener Optimizer control system means the solids inventory within the tank can be maintained to ensure a consistent underflow density, stable process, and improved overall thickener performance, according to the company.

In addition to mechanical improvements, process control has been further developed to stabilise and optimise the performance of the paste thickener, Outotec said.

The company said: “Outotec’s ACT Thickener Optimizer utilises a multivariable controller to manage process changes and the associated delays in the response time of the thickener that can be challenging for traditional control systems. It can also be configured to manage the effects of variable feed types to ensure optimum performance despite changing inputs to the process. Short installation and configuration time of the system is coupled with on-going services to ensure a practical yet flexible long term control solution.

“Our application-specific design of the thickener begins with the use of methods such as discrete element modelling to understand solid particle movement within the thickener, computational fluid dynamics for feed system design and finite element analysis for structural steel design. Our paste thickening solutions are also designed with ease of maintenance in mind, with a skid-mounted hydraulic power unit for centralised connection of hydraulic hosing from the rake lift cylinders and drive unit.”

Other key design features include:

  • Low profile rakes with tie-cable load sharing that minimise rake drive torque requirements;
  • Rake blades supported by thixoposts to move the rake arm away from the highest density thickened solids;
  • High sidewall and steep tank floor slope for more efficient dewatering of flocculated solids and compaction of the bed, as well as better transport of the solids inward toward the tank discharge point;
  • High installed drive torque to move the rake blades through beds of thickened solids with high yield stress and viscosity, and;
  • Feed systems with break tanks when required for different thickener feed situations, including our patented Vane Feedwell, and break tanks inside the thickener perimeter to save on site layout space.

“Beyond technology and equipment, Outotec provides complete solutions for thickening needs,” the company said. “Proven design features and process guarantees, combined with lifecycle service support, help ensure operational reliability. We can also support customers with ongoing operation and maintenance services after plant commissioning.”