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Reclaiming tailings sustainability

Published by
Global Mining Review,


Water requirements for intensive applications such as hard rock mining and oil sands processing have historically been supplemented by local water sources. Today, these applications face new challenges as the focus shifts to how operations can minimise their environmental footprint, but continue to improve productivity while also complying with new regulations. This global shift in focus reveals the need for increased sustainability in tailings processing.

The way forward is not only installing energy-efficient products that offer improved reliability, but also working directly in partnership with companies that can design engineered-to-order solutions tailored for optimised and sustainable results.

One of the ongoing challenges for customers is tailings reclamation. The question of how best to reduce dependence on tailings ponds, yet expedite reclamation of both water and product in the process, was at the top of the list for one Weir Minerals customer.

Pumping stations are a critical element of tailings management, providing the energy needed to drive the downstream processes. Static slurry pumphouses have until now been the norm, but they are costly and present many limitations when considering alternate tailings processing techniques.

When the customer approached the Weir Minerals Canada dewatering team with a vision to mobilise the pump system for their new tailings treatment process, initially they did not even know if it was even possible.

“The sheer size and energy requirements of the equipment needed for the application meant that this was a huge undertaking from the beginning. You do not normally think of 3500 hp pumps and 160 t of equipment as mobile,” explained Kris Kielar, Product Manager for Dewatering Engineered to Order Solutions at Weir Minerals Canada.

The Weir Minerals team worked directly with the customer to design an innovative booster pumphouse, engineered especially to manage the Non-Segregating Tailings (NST) on site. The proposed solution was an integral piece to reduce the tailings pond footprint on site through accelerated fines capture and decreased fluid tailings production, thus releasing more water for recycling and thereby reducing necessary water intake from local sources. This in turn would expedite reclamation to create landforms that support wetlands and self-sustaining forest ecosystems.

The standard tailings processing model takes time, but this solution successfully reduced tailings residence time with a total solution realised through Weir Minerals equipment. Multiflo® pump barges mounted with Hazleton® submersible slurry pumps extract the target fluid tailings that feed high-powered, land-based, Weir re-locatable pump houses. Inside the pump houses, Warman® slurry pumps boost recovered tails from the pond to drive the new tailings treatment process plant.

“By working directly with the customer, we understood not only their desired outcome, but also the existing capabilities on site. We stayed close and were able to proactively tweak our design based on the customer’s needs, so when it was time to present, we were already prepared with the ideal solution,” added Kielar.

The Weir Minerals dewatering team designs solutions using highly engineered and reliable equipment that is not just efficient, but also adds value to a customer’s site process. For example, the entire module of the Weir mobile pumphouse can be built offsite at a much lower cost than traditional pumphouses, which are built in-situ. Building a pumphouse in-situ is time-consuming and expensive, as the method requires skilled trades to work for extended periods of time in remote locations.

“Competitor pumphouses built using in-situ construction methods can more than double the construction time and costs compared to the steel fabrication methods we have used,” stated Peter Pavlin, Weir Minerals’ North America General Manager of Engineering.

The Weir mobile pumphouse is an innovative solution that provides a variety of pumping possibilities for intensive tailings applications. It is designed to relocate across the site using especially engineered, military-style skid and ‘jack-and-roll’ elements and a novel patent-pending pump/motor suspension system, providing a unique advantage in mobile pumphouse technology. These advances provide operators with distinct advantages over traditional fixed-in-place designs, creating a more agile and cost-effective solution.

“Our design sets a new standard for tailings management applications. Other pumphouses in the market are static and often cause difficulties for operators when they wish to expand into new areas, as they must discontinue service, resulting in a large capital expenditure. Our solution has overcome these limitations by providing the customer with the tools to rapidly reconfigure a changing pumping network and move it to other sections of the tailings pond,” explained Pavlin.

The Weir mobile pumphouse incorporates an integral gland water supply system and a separate eHouse for power control and remote communication. A patent-pending, three-point pump base mounting system allows the base and skid to act independently, minimising the risk of pump and motor shaft misalignment during operation and the relocation process.

“Establishing relationships with our customers is just the beginning,” Kielar explains, “By working closely together over several years, we learn the ins and outs of their operation. We hear feedback directly from the people who work with our equipment, and that helps us create even better solutions.”

Having in-house engineering expertise means that the company works directly with its customers to create solutions that consolidate waste to recover more product more easily, while also extracting reusable water and sending it back into the process plant more quickly than other standard solutions.

Read the article online at: https://www.globalminingreview.com/environment-sustainability/07092020/reclaiming-tailings-sustainability/

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