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, Weir Minerals says.
The way forward is not only installing energy-efficient products that offer improved reliability, but also working directly in partnership with companies such as Weir Minerals that can design engineered-to-order solutions tailored for optimised and sustainable results, the mining OEM explains.
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 top of mind 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 pump houses have, until now, been the norm, but they are costly and present many limitations when considering alternate tailings processing techniques.
A new approach to tailings reclamation
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 didnt 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 dont normally think of 3,500 hp (2,610 kW) pumps and 160 t of equipment as mobile, Kris Kielar, Product Manager for Dewatering Engineered to Order Solutions at Weir Minerals Canada, explains.
The Weir Minerals team worked directly with the customer to design an innovative booster pumphouse, engineered especially to manage the non-segregating tailings on site. The proposed solution played an integral role in reducing the tailings pond footprint on site through accelerated fines capture and decreased fluid tailings production, thus releasing more water for recycling and reducing necessary water intake from local sources. This, in turn, would expedite reclamation to create landforms that support wetlands and self-sustaining forest ecosystems, according to Weir Minerals.
The standard tailings processing model takes time, but this solution dramatically reduced tailings residence time with a total solution realised through Weir Minerals equipment, it said.
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.
Kielar continued: 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 customers needs, so when it was time to present, we were already prepared with the ideal solution.
Engineering for extra value
The Weir Minerals dewatering team designs solutions using engineered and reliable equipment that is not just efficient, but also adds value to a customers site process, it says.
For example, the entire module of the Weir mobile pump house can be built offsite at a much lower cost than traditional pump houses, which are built in-situ, Weir Minerals said. Building a pump house in-situ is time-consuming and expensive, as the method requires skilled trades to work for extended periods of time in remote locations.
Peter Pavlin, Weir Minerals North America General Manager of Engineering, said: Competitor pump houses built using in-situ construction methods can more than double the construction time and costs compared to the steel fabrication methods we have used. When faced with a complex problem from a customer, we always evaluate the situation holistically and strive to develop a new approach. That is the beauty of engineering, the possibilities are endless, and the Weir Engineering Team have the expertise and tenacity to go against the norm and develop novel and cost-effective solutions.
The Weir mobile pump house provides a variety of pumping possibilities for intensive tailings applications, according to the company.
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 pump house technology. These advances provide operators with distinct advantages over traditional fixed-in-place designs, creating a more agile and cost-effective solution, according to Weir Minerals.
Pavlin explained: Our ground-breaking design sets a new standard for tailings management applications. Other pump houses 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.
The Weir mobile pump house 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, according to Weir.