WEIR Minerals has considerably enhanced its global tailings solutions capability through establishment of the Weir Technical Centre (WTC) in Melbourne, Australia. The centre has become a global hub of tailings expertise for Weir Minerals, providing innovative and sustainable tailings and pipeline solutions for its customers worldwide.

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The Weir Technical Centre in Melbourne has enhanced Weir Minerals’ global tailings solutions capability.

“Our tailings product offering with world-renowned performance combined with our global service footprint, ensures customers receive high quality tailings solutions,” says Weir Minerals director of technology John McNulty.

Tailings handling vital

Mine operators are continually looking for solutions for the safe transport, storage and disposal of tailings, as well as the opportunity of converting tailings into construction materials and mine backfill.

“The handling of tailings is one of the most important factors going forward in mining. A tailings dam is an engineering structure that has a design lifetime of 1000 years, which can be an immense challenge to achieve,” says Weir Technical Centre general manager operations and development Nils Steward.

The increase in tailings dam failures worldwide has a negative impact on a mining company’s social licence to operate (SLO). With this in mind, an efficient tailings management system is a necessity and integral to how a company operates from an environmental and safety perspective.

Another factor to consider is decreasing ore grades, resulting in increased mining volumes to achieve the same mineral production. This is increasing the production of tailings on mine sites.

“Typically tailings are moved as slurry using pumps, and this is where Weir Minerals’ expertise comes to the fore. We have more than 140 years of engineering expertise and continue to advance our pumping technology. With an extensive pump range, and more than 100 engineers across the globe focusing on pump design and new product development, our highly engineered pumps are constantly modified and enhanced,” says John McNulty.

Weir Minerals designs and develops a number of products that specialise in the transport of tailings. “Our GEHO pumps are expertly designed to transport tailings over long distances and are some of the world’s most advanced positive displacement pumps,” John McNulty continues. “Our renowned Warman slurry pump range is a recognised global leader in the mining industry, and the horizontal and vertical slurry pumps are specifically designed for heavy duty applications including handling tailings slurries.”

All Weir Minerals’ tailings products and solutions are backed by continuous advanced research and in-house test facilities such as those available at the WTC.

Pipe loop testing and research

Since incorporation of the WTC into the portfolio in 2016, Weir Minerals has been busy enhancing its tailings offering to customers around the globe.

The WTC is dedicated to designing site specific transport systems for mining operators using its proprietary pipe loop test facility, dewatering and separation capabilities together with its extensive experience in mining, tailings and backfill markets.

“We have the technology to test pipeline and tailings solutions for our customers before they are installed on site. By testing materials and equipment, we can fully understand the performance of the selected pumps when transporting solids, which provides us with valuable insight into pump performance, efficiency and predictive maintenance,” says Nils Steward.

“Mineral slurries vary in many ways - mineralogy, particle size distribution, solids concentration and chemistry - and thus each slurry behaves differently when in a pipe system. Therefore the relatively simple task of pilot test work is a very important activity as it helps determine the best solution for our customers’ sites while reducing the overall design risk.”

Pipeline selection in terms of size, material, as well as possible lining types, is essential to ensuring overall pipeline transport success, efficiency and system longevity. The selection of pipe size, together with pump and motor specifications, pose the greatest risk to any pumping operation. The WTC can assist with the correct slurry characterisation and pipeline pressure gradient data to reduce, or remove, this process risk to the operator.

Using data generated at the WTC, Weir Minerals tailings’ specialists can specify tailings handling products and processes to suit operators’ site specific environmental and operational conditions. This helps mine operators minimise power and water consumption as well as the risk associated with design.

Tailings disposal

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Flow rates, temperatures, pressures, solid concentrations and power requirements can be monitored through the closed loop pipeline system.

There are a number of opportunities operators can investigate when considering the disposal of metallurgical tailings. In order to create a more effective tailings disposal solution, a deeper understanding of tailings properties is required.

“At the WTC, we analyse an operator’s tailings to determine the opportunities in which the tailings can be modified, utilised or transported,” says Nils Steward.

Experts must address and analyse the many different tailings characteristics listed, as well as the placement properties required in backfilling or typical tailings storage disposal. The WTC has the capability, besides pipeline and pump monitoring for pressure gradients and power draw, to develop and test tailings in mine construction products and bulk storage facility placed material. Based on this test work the WTC can determine the opportunities for total tailings utilisation, the processes required to produce tailings products and the most suitable form of transportation.

Weir Minerals is currently focused on transporting the final tailings product using pumps as the delivery method.

“We have over 100 years’ experience in pumping and pipeline infrastructure. When you combine that with our stress and transient analysis through the WTC and our extensive practical experience, we can offer customers a complete solution to minimise risk,” says Nils Steward.

A complete tailings solution may include a number of opportunities, singly or severally - tailings bulk disposal in a tailings storage facility as a settling slurry of a ‘dry pumped’ product; backfilling as a hydraulic or paste product; or as a value added ‘tailings as resource’ product.

Tailings as a resource

From the WTC, Weir Minerals can help customers to improve their tailings disposal in a safe and stable manner, as well as present alternative options for tailings utilisation.

There are opportunities for mine sites to convert tailings into resourceful products. Sustainable development in mining can be extended to the management and handling of tailings and there are multiple ways in which operators can positively reuse tailings.

“We need to rethink the way we view tailings. Yes, tailings is a waste product, but this can also be used as a value added product for future resources. There are many opportunities to use tailings as a resource, and we are beginning to see a lot more demand for the use of tailings products in infrastructure,” states John McNulty.

The WTC has the technology and expertise to turn waste into useful products. By modifying tailings, the team has an excellent track record in creating a number of by-products including concrete, shotcrete and support structures.

“We have developed many alternative products from tailings - from the 200MPa tailings backfill integral to the innovative ‘Drill and Fill’ mining operations in South Africa to the 1km of a tailings based concrete road cast on a mine site to hold the weight of 30 tonne trucks that has been operational for over a year. We truly believe there is scope to produce a lot more tailings products in the future and will continue to research opportunities in which to do so,” says John McNulty.

Backfilling

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Tailings management is one of the most important factors for mining around the world.

Backfilling involves the return of metallurgical tailings underground to fill the voids created by the mining process and is viewed as a sustainable way to reuse tailings for safety and support. Backfill usually comprises the metallurgical tailings that are dewatered plant tailings or a cyclone product that may include a cementitious component. Alternatively the metallurgical tailings may include sand or aggregate and can be used with or without cementitous binder components.

The WTC can evaluate the suitability of various dewatering and thickening technologies for a specific application and, with their in-house global leadership expertise in backfill systems, can carry out the required design for the manufacturing process and reticulation systems. The WTC expertise covers the full spectrum of backfill systems from hydraulic to paste, and paste aggregate backfill.

“We deal predominantly with high solids concentrations which is becoming more important in a water constrained and environmentally sensitive industry. Our depth of experience and knowledge together with the delivery of innovative designs has provided effective solutions to meet our clients’ needs around the world,” says Nils Steward.

The WTC can design backfill products that meet the placement and strength requirements of any mining application, from consolidated uncemented tailings, to high tech 200MPa backfill materials. This is achieved by testing the tailings materials before subsequently developing the necessary backfill mix design.

Weir Minerals has ambitious growth plans to globalise the WTC, planning to open up additional technical centres around the world to enhance the tailings offering for customers.

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