A golden partnership: Metso’s MHC500 Hydrocyclone increases efficiency and cost savings for Björkdalsgruvan

As one of the few gold mines in Sweden – and one of the largest gold mines in all Northern Europe – the Björkdalsgruvan gold mine boasts high production expectations. Owned by Mandalay Resources and situated just 40 kilometers from Skellefteå, this mine has been a vital asset in operation since 1988, steadily expanding its capacity over the years. With a processing capability of 1.3 million tonnes annually, Björkdalsgruvan produced 42,148 ounces of gold in 2023 and anticipates an even more robust production in 2024, aiming for 43,000 to 47,000 ounces.

Metso has a long and successful history with Björkdalsgruvan, highlighting the mine's commitment to efficiency and quality. Having supplied equipment and services to the site since its inception in 1988, there is a variety of Metso equipment present, such as slurry pumps, Lokotracks, flotation equipment, crushers, thickeners, screens, mills and more.

“A lot of our products are already there, so it was a natural move for them to reach out to Metso to supply a solution,” says Gustav Forsman, Sales Support Specialist, Metso. “Especially with our new cyclone in play, it’s new for us and we have an established relationship already, so the trust was there.”

Overcoming common operational challenges

Björkdalsgruvan encountered frustrations with their tailings hydrocyclone, grappling with high wear rates and underwhelming performance. With the operating pressure being so high, the hydrocyclone struggled to deliver the right product, which is very important for this kind of tailings application due to rules and restrictions of the outputs to avoid severe dam failure.

In addition to this, the escalating wear rates were translating into high operating costs. The operating costs were primarily driven by the parts and labor of replacing the hydrocyclone and feed pump wear parts during unnecessary frequent shutdowns.

This a common challenge within the industry that many mines around the world are facing. Inevitably, the pressure will impact the wear on the hydrocyclone, and with higher pressure comes higher wear. Thus, achieving the same product using less pressure leads to reduced power consumption on the hydrocyclone feed pump, resulting in significant cost savings on both electricity and wear parts. It is a delicate balance in finding the optimal pressure, and extremely important as it has the ability to not only extend the hydrocyclone's lifespan but includes benefits such as increased efficiency, performance, cost savings, environmental advantages and more. Mitigating dam failure risks is crucial in preventing catastrophic environmental consequences, and it’s important to recognize that key factor.

The Metso solution

Metso experts responded to the challenges challenges at Bjorkdalsgruvan with a tailored solution aimed to address their concerns while demonstrating cost-efficiency and product quality improvements. Enter: Metso’s MHC500, a singular hydrocyclone equipped with an inlet adapter for real-time inlet pressure measurement.

This next generation hydrocyclone, the MHC™ Series, revolutionizes the classification process by balancing grinding circuit costs with unparalleled plant performance. Its innovative inlet head design ensures seamless material flow, critical for achieving high-level wet classification in mining, especially for particles finer than 1mm in water.

“It was during the initial quoting stage that we were able to demonstrate that our MHC500 would operate at significantly lower pressure and achieve the critical product specification they required,” says Gustav. “Our simulation tool used both theoretical and practical data to make a reliable hydrocyclone selection and it has proven, specifically in this case, to be extremely accurate.”

Remarkably, the data provided by the simulation tool used in the quote stage ended up being almost exactly on point with the pressure that they achieved on site.

Their swift transition from proposal to order – initially quoted in September 2021 and secured by late October – marked a rapid turnaround. With a pre-established and successful partnership already built, Björkdalsgruvan put their trust in Metso’s equipment and simulation tool – a decision that continues to prove its worth over time.

“We have a real commitment to support, so we had a salesperson on site assisting during startup and commissioning. We wanted to make sure we had local presence throughout,” says Gustav. “It was important for us to be there for the customer during all stages, and when I went to site to support further, the MHC500 was already in operation and working as per their requirements. Everybody was happy!”

Lower pressure leads to higher efficiency

Due to the superior MHC design, Metso’s solution offers a range of substantial benefits. Notably, its ability to operate at lower pressure, significantly boosting product quality and capacity.

“Operating at a lower pressure was the standout feature in this case, because the level of capacity was such a huge difference compared to the competitor cyclone,” says Gustav. “We have been able to deliver the product in a way that their old supplier could not, and the stark difference between the two was a major factor here.”

The wear and tear on the existing cyclones due to high pressure demanded frequent replacements, impeding product quality and delivery. With Metso’s MHC500, this not only extended hydrocyclone lifespan but ensured compliance with strict tailings product regulations.

“The wear part on the existing cyclones did not last long at all, so they needed to frequently shutdown the cyclone to do replacement,” says Gustav. “There are such high restrictions in tailings products – for good reason – so they needed a solution that fixed their issues with the high pressure, but also stayed within restrictions and still have high production capacity. Thankfully, the MHC500 achieved that.”

Significant cost savings

The MHC500's efficiency and unit capacity translated into substantial operational cost reductions for Björkdalsgruvan. Lower pressure requirements directly affected electricity and wear part expenses associated with the hydrocyclone feed pump, significantly reducing the costs.

With the distinctive design inlet and head design, this allows it to operate at a lower pressure without compromising on product delivery. Consequently, this leads to minimized downtime and maintenance costs. Wear part consumption for both the MHC5000 and the Metso cyclone feed pump has been reduced, encouraging ongoing cost savings within the maintenance space.

Remarkably, these savings translated into the MHC500's capital costs being reimbursed in just a few months of operation - a testament to its cost-effectiveness.

Improved safety and sustainability

Beyond operational efficiency gains and cost savings, the MHC500 contributed significantly to improving safety and sustainability. Consistently meeting product requirements and limiting waste, this mitigates the risks associated with dam failures as well as limits the amount of maintenance shutdowns.

“With tailings products, it’s very restricted and by law, it needs to deliver a certain product,” says Gustav. “The product we’re achieving here is building the wall of the dam and when the dam is filled with water, the wall needs to handle the pressure from the water and the weight. Understandably, it needs to be safe, and you need to have control of the product.”

At Metso, safety is our top priority and at the core of everything we do. Safety is a sign of quality, and ensuring a safe and secure performance is one of the keys in ensuring sustainable business. Therefore, it is an integral part of the business decision-making and operational processes. 

Due to the MHC500's efficiency enhancements that lead to decreased power consumption, this consequently reduces electricity costs – an instrumental achievement for Björkdalsgruvan when it comes to sustainability. This is especially important in the context of strict tailings product regulations and their critical role in dam wall construction.

The cyclone feed pump was already a Metso pump. Thus, with the hydrocyclone replacement to MHC500, the Metso pump did not need as much motor power.

“This goes hand-in-hand with the pressure – less pressure, less energy consumption,” says Gustav. “When I prepared the process data, the difference between the two hydrocyclones was huge since the pressure used to be so high. We calculated how much they saved on energy and energy costs per year, and it was extremely substantial. So environmental factors are also impacted by this lower pressure.”

Customer satisfaction leads to continued collaboration

The longstanding partnership between Björkdalsgruvan and Metso stands as a testament to our commitment to customer satisfaction. Björkdalsgruvan has found the Metso approach and expert understanding to be instrumental in achieving their operational goals.

From first contact to on-site operation, Björkdalsgruvan has been pleased with Metso’s way of working and the initiative taken to address their challenges. Their satisfaction stems from a variety of reasons, such as Metso’s proficient grasp of their needs, the simple and streamlined order process, punctual delivery, and of course, the continuous support throughout the process – before, during, and after operation.

The simplicity of the order process made the entire experience more efficient, ensuring minimal disruptions to their operations. With ongoing support throughout the journey, from initial discussions to full scale operations, Metso has provided Björkdalsgruvan with peace of mind and confidence in the solutions.

The site was also pleased that Metso's initial simulation was validated during operations which led to enhanced product quality and operational efficiency while curbing costs. The timely delivery of the MHC500 enabled the site to begin commissioning as per their schedule. This was executed successfully in March 2021, and has since been in continuous operation, further demonstrating the effectiveness of the solution in meeting their operational needs.

The high level of customer satisfaction has not only reinforced our partnership, but also resulted in the opportunity to replace the second and final competitor tailings hydrocyclone on-site in 2023. This continued collaboration allows Björkdalsgruvan and Metso to continue as reliable partners in their pursuit of operational and environmental excellence. At Metso, it is our core expertise to help our customers transform the industry. That is why we are the partner for positive change.