Tag Archives: tailings

Test work proving up FLSmidth’s ‘game-changing’ Ecotails solution

Bulk handling, Environmental, Mineral processing, Mining equipment, Mining services, Precious metals, Sustainable mining, Water management, , , , , , , ,

Testing by one of the world’s leading gold producers has confirmed FLSmidth’s Ecotails™ solution will be a game-changer for the mining sector, according to one of the company’s regional dewatering product line managers.

The solution, which combines filtered mine tailings with waste to form a GeoWaste, lowers water usage, rehabilitation costs and tailings footprints, according to the company.

Back in 2017, FLSmidth and Goldcorp signed an agreement to develop EcoTails, with the solution being studied for full-scale testing at Peñasquito, an operation with an average daily throughput of 130,000 t/d.

FLSmidth Regional Product Line Manager (Dewatering), Leonard Neluvhola, said the Ecotails solution is nearing the end of a lengthy testing process with the company, now called Newmont Goldcorp following a recent transaction.

“The success of its application to date confirms that Ecotails will be a game-changer for the mining sector,” Neluvhola said. “Not only can mines improve their environmental performance by applying this system, they will also see bottom line benefits too.”

He said the Ecotails solution involves dewatering and filtering tailings to a point where moisture content is just 10% to 25%.

“Up to 90% of the water in tailings can therefore be reused in the plant,” he said. “This is a vast improvement on pumping highly diluted slurry to a conventional tailings dam, where the water is lost to evaporation.”

The drier tailings are then mixed with the mine’s waste rock, after it has been sized and screened to be transportable by conveyor. “The resulting GeoWaste can be placed by a stacking system, as it is much more stable than wet tailings and can be stacked higher on a smaller footprint,” FLSmidth said. “This helps to address the serious concern mines have about the large footprints consumed by their tailings dams and waste rock dumps.”

In addition to its greater stability, GeoWaste is more conducive to vegetation growth, according to the company. “It is an ideal medium for concurrent environmental rehabilitation,” FLSmidth said. “The concurrent approach is becoming more popular, as it can mitigate the costs and risks of mine closure. Wet tailings can also present a greater danger of land contamination through leaching.”

Neluvhola said: “With our Ecotails experience and complete system offering, FLSmidth can provide a complete materials handling solution.” This includes crushers, sizers and screens, KREBS® pumps, thickeners and filters, conveyor and stacking systems, conducting tests and studies, system engineering and automation systems.

Neluvhola highlighted that FLSmidth in South Africa collaborates with customers on in-depth test work to ensure the application of Ecotails on their mines is fit for purpose.

“We can conduct testing at laboratory scale, and then advance to pilot stage when a mini-plant can be operated on site,” he said. “This allows us to test the technology using the customer’s own mined material in the thickening, filtering, conveying and blending phases to inform our technical designs.”

Outotec looks for consistent and efficient dewatering with new paste thickener

Environmental, Industrial minerals, Mineral processing, Mining equipment, Mining services, Sustainable mining, Water management, , , , , , , , , , , , ,

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.”

Vale plans significant investment in dry processing technologies, Reuters says

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Vale reportedly plans to invest $2.5 billion on, predominantly, dry processing technology as it looks to draw a line under the recent tailings dam failures that have occurred at its Brazil operations.

Reuters, citing emailed responses from Vale’s Director of Ferrous Planning and Development, Fabiano Carvalho Filho, said the Brazil-based miner would spend the amount over the next five years, with the funds mainly used to convert Vale’s Carajas iron ore mining operations in the northern portion of the country to 100% dry tailings facilities.

The news came on the same day the company released its March quarter financial results, which saw the miner report a $1.6 billion loss on the back of the recent Brumadinho dam rupture.

The company is looking to increase its dry processing operations to 70% of its overall iron ore output by the end of 2023, from 60% currently, according to the Reuters report.

Of the 17 processing lines of Plant 1 at Carajas, 11 are already using dry technologies and the remaining six wet lines will be converted by 2022, Carvalho Filho reportedly said.

In addition, the investments will also go towards two projects in Minas Gerais – one for a new iron ore processing complex, with the other focused on restarting a previously operational mine – the news agency said.

The dry processing spend is part of an existing program under which Vale has invested almost $17.5 billion over the last decade, Carvalho Filho told Reuters, adding that the investments were not directly tied to the recent tailings dam spills at the Brumadinho and Mariana dams.

Heron concentrates on 1.5 Mt/y production goal at Woodlawn zinc-copper mine

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Heron Resources says it has successfully commenced processing activities at its Woodlawn zinc-copper mine in New South Wales, Australia.

Reclaimed tailings from hydraulic mining operations are now being processed in the new flotation treatment facility; a significant milestone that marks the start of full production activities, the company said.

Attention has now turned to the ramp-up program with a focus on increasing throughput to nameplate capacity of 1.5 Mt/y, achieving design recoveries and meeting product quality specifications for the three base metal concentrates to be produced at Woodlawn.

In addition, preparation for the first processing campaign of high-grade underground ore is well advanced and will proceed following the current ramp-up program, Heron said.

“Underground mining continues to perform well, with production in the last three months exceeding plans, and development ore from the G2 Lens stockpiled at the crushing circuit in readiness for processing,” the company said.

Based on the current ore reserves mine plan, the project is expected to produce three concentrates at an average annualised gross production rate at steady-state of 40,000 t zinc, 10,000 t copper, 12,000 t lead, 900,000 oz silver and 4,000 oz gold over an initial mine life of 9.3 years. The company says there is significant potential for mine life extensions through the conversion of high-grade underground resources and further exploration success.

Heron’s Managing Director and CEO, Wayne Taylor, said: “We are excited to have now achieved this significant milestone in the transition from explorer to producer with the processing of the first reclaimed tailing through the Woodlawn plant. Commencing operations is timely, and we look forward to taking advantage of continuing favourable conditions in base metals markets as we ramp-up our operations.”

The feasibility study for the “starter case” at Woodlawn contemplated campaign treatment processing of 1-1.5 Mt/y from two separate production sources – underground and tailings.

The company kicked off commissioning at Woodlawn back in December.

 

Wood and Cementation Americas complete Terra Nova Technologies deal

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Wood says it has completed the sale of conveyor systems business Terra Nova Technologies (TNT), close to six weeks after the deal was announced.

Following a strategic review of its portfolio, Wood identified potential asset disposals which were expected to generate proceeds in the range of $200-$300 million, with the TNT sale making a “good contribution to the asset disposal program”, it said.

The TNT business was sold to Cementation Americas, a firm owned by Murray & Roberts Holdings Ltd, for $38 million.

Back in late-March when the deal was announced, David Kemp, Wood Chief Financial Officer, said: “Terra Nova Technologies has a strong track record in delivering material handling equipment to our customers. Wood’s strategy going forward is to focus on asset-light solutions rather than the manufacture/fabrication of equipment.”

Cementation Americas said TNT has earned a solid reputation for providing quality design, supply and commissioning services for crushing and screening plants, overland conveyors, heap leach systems and mobile stacking systems for waste and dry tailings.

Justin Oleson, President of Cementation Americas, said at the time: “The purchase of TNT fits well within Cementation’s strategy to improve our ability to serve clients, both geographically and across the mining value chain. The combining of Cementation and TNT complements both our underground and surface design/build portfolios, and better positions Cementation to support our client’s total mining needs.”

GreenGold’s ReCYN to detoxify tailings, recover cyanide and copper at Martabe

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Technology provider GreenGold says it has been awarded a ReCYN™ design and install contract with PT Agincourt Resources to detoxify tailings and recover cyanide and copper at its Martabe gold-silver operation in Sumatra, Indonesia.

Jakarta- and Perth-based GreenGold will deliver the project with preferred fabricators for specialist equipment packages, the company said.

In a report published last year, Whittle Consulting called the ReCYN process “a world-leading approach” in cyanide recovery, metal recovery and tailings detoxification. “Based on an innovative resin-bead absorbent, ReCYN reduces cyanide consumption by 50%, capturing free cyanide from the plant tailings and recycling it back into the leach circuit while recovering metal complexes and making them available for sale,” Whittle said.

Whittle also said adopting the technology could provide a $126.9 million upside to the project.

GreenGold said it had received the contract following a record influx of enquires for the technology.

GreenGold CEO, Malcolm Paterson, said of the Martabe contract: “We have come up with an elegant design to fit the space constrained site. We also will be recovering cyanide and copper which previously was destroyed or sent to tails, turning a cost into an economic benefit for the mine.

“We are looking forward to delivering on this strategically important project, and continuing to build on our proven metallurgy and process capability within the precious/base metals sector globally.”

The Martabe mine has a resource base of some 7.4 Moz of gold and 69 Moz of silver.

Antofagasta backing ‘digital transformation’ of operations

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Antofagasta, in its 2018 financial results, has promoted its innovation focus, saying it is critical to creating long-term value and being “a key enabler of safe, sustainable competitiveness and growth”.

One of the ways the company is seeking innovative solutions is through the increased use of data and technology, which it calls “the digitalisation of operations”.

Antofagasta said it is investing significantly in this area, which has an implementation budget of $40 million, to strengthen its technological platform, including critical operating systems and connectivity.

The company has also applied advanced data analytics at its processing plants to better understand and improve their performance.

In the meantime, it said work was underway on the design of a Remote Centre that will allow integrated operations management at its Centinela operation in Chile. Service provider Wood is currently preparing a prefeasibility study for this technologically-advanced integrated operations centre, which includes cloud data storage and information management for its operations, easily accessible from anywhere in the world.

Antofagasta continued: “It’s not just at the operating level that there are benefits of improved data.

“Los Pelambres constantly monitors its tailings deposits and, as part of the Programa Tranque project, expects to start releasing the monitoring results online early next year. This will provide the community with real time information, helping to build trust between ourselves and our neighbours,” the company said.

Programa Tranque contemplates the development of an online monitoring system of tailing deposits to transmit, process and broadcast, in a user-friendly way, updated physical and chemical indicators of the deposits.

It incorporates the best available technologies and innovative mechanisms for the measurement of critical parameters and variables, as well as an information management platform to communicate information to authorities, mining companies, and the community, allowing an early warning system to be activated ahead of potential emergency situations.

In addition to Antofagasta, BHP and Codelco are partnering on this five-year programme that seeks to position Chile as the leading country in information transparency related to the performance of its tailing deposits.

Kirkland Lake Gold cements approvals at Fosterville gold mine

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Kirkland Lake Gold has received regulatory and planning approval for an on-site cement plant at its rapidly-expanding Fosterville gold mine in Victoria, Australia.

Victoria’s Minister for Resources, Jaclyn Symes, confirmed the approvals on site at Fosterville last week.

The new cement infrastructure plant will enable by-product rock to be re-inserted underground, reducing tailings and extending the life of the mine, according to the government. It will also lead to production increasing at the underground mine, it added.

Estimated gold reserves at Fosterville were recently upgraded 60% to 2.7 Moz, with production in 2019 set to come in at 550,000-610,000 oz, up from 350,000 oz in 2018.

In August, Kirkland Lake Gold secured GR Engineering’s EPC services for a paste backfill plant at Fosterville which, when in production, could produce 65 m³/h of paste to fill the stopes in the gold mine.

Tailings monitoring could go autonomous, Mining3 says

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Mining3 says it and The University of Queensland, in conjunction with the Australian Coal Association Research Program (ACARP), are currently in the process of building prototype autonomous sensors for the constant monitoring of tailings and spoil storage facilities.

The Australia-based company said: “Tailings impoundments are one of the largest man-made structures on earth and ensuring their integrity for the safety of human life, the environment and property are critical in today’s mining operations. Past and recent catastrophic tailings dam failures have placed an urgent need for improved waste disposal, storage processes and monitoring capabilities.”

Currently, the integrity of the tailings dam infrastructure is monitored by mining staff walking along the, potentially unstable, perimeter and visually inspecting the exterior. Piezometer-like devices are also placed throughout dams to measure changes in liquid pressure. “Combined, these methods provide subjective data that cannot deliver an ongoing and accurate assessment of the integrity of these waste storage facilities,” Mining3 said. “Without a reasonable assessment of these large structures, there is no way to identify if or when one might fail.”

With a web of small, interconnected sensors spread across a tailings dam or spoil dump, Mining3 says accurate measurements in the change of water pressure or movement in the soil can be delivered to the surface in real-time. “This provides up to date readings of environmental factors that can affect overall wall stability, limiting the need for staff on the ground,” the company added.

Mining 3 and the university’s research will also delve into identifying indicators and precursors to failures, in relation to data collected from these sensors. “This could revolutionise the understanding of these storage facilities. By understanding the causation, steps can then be taken to minimise risk in the future,” Mining3 said.

“The current project addresses key industry outcomes surrounding safety and the removal of personnel from hazardous situations such as those involved in ground stability, the investigation of material properties and their implications in the design and functionality of a dump site, and the investigation into aspects of effective mine closure and the long term impacts associated with tailings dams and spoil dumps.”

Outotec processing expertise and tech on its way to Mexico precious metals project

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Outotec has won a contract for the delivery of a complete minerals processing plant for a precious metals project in Mexico, as part of wider €30 million ($34 million) order.

The company will also deliver process equipment for upgrades of two other sulphide silver ore processes for the same customer.

The total value of the contracts booked in Outotec’s December quarter order intake is approximately €30 million ($34 million), Outotec said.

The scope of the delivery includes the entire process flowsheet of grinding mills, flotation machines, concentrate and tailings thickeners, as well as concentrate filters, automation, and various spares and supervision services for the new precious metals concentrator.

For the upgrade of existing silver processes, Outotec will deliver additional flotation machines and multiple fine grinding equipment for improved recovery.

The deliveries will take place in the end of 2019, Outotec said.

Kimmo Kontola, Head of Outotec’s Minerals Processing Business, said: “We are pleased that we were chosen to deliver our leading technologies and services that enable our customer to improve their profitability in a sustainable way.”

The company was also recently awarded a pressure leaching and solvent extraction technologies for a battery chemicals plant to be built in Sotkamo, Finland. The total order value booked in the December quarter order intake for this contract is some €34 million.