The importance of analyzer maintenance in meeting the challenges of declining ore grades

Metso Analyzers have been a market leader for online elemental analysis in minerals processing since their introduction in 1968. As ore grades continue to decline, they have become an increasingly popular solution to improve yields. By providing instant readings on ore quality at various stages of the mining process, analyzers allow operators to respond quickly to changes in metallurgical performance while monitoring the impact of their actions in real-time.

The fact is, even a small increase in recovery rates can result in substantial financial benefits. On top of that, using analyzers reduces the need for manual sampling and minimizes unnecessary downtime, resulting in reduced costs and labor requirements.

”If you have accurate measurements then you can make the appropriate controlled actions, so the metallurgical performance improves,” says Juha Timperi, Director, Analyzer Solutions, Metso. ”Calibration of the critical sample lines improves the accuracy of the analyzer, resulting in better metallurgical performance of the plant due to improved process control.”

Digitalization plays a key role in increasing accuracy, availability, sustainability and safety, so it is no surprise that operators are looking to make their sites smarter, and more data-driven. With the introduction of remote monitoring, there is a clear increase in benefits, such as improved plant visibility in terms of maintenance planning based on components/equipment condition as well as effective management of critical spare parts stock at the customer’s warehouse, based on data from the equipment.

With the development of new measurement technologies, the value of utilizing analyzers continues to grow. For example, the new Metso Courier 6G analyzer released in 2020 allows operators to measure gold and platinum group metals directly in the flotation process. By enabling real-time data and control, operators can measure exceedingly small quantities of precious metals in the circuit, which was not possible before. The Courier 8 analyzer is also the first of its kind to introduce Laser Induced Breakdown Spectroscopy (LIBS) analyzer to the process, which gives operators the ability to measure lighter elements such as lithium. With the increasing demand of battery metal applications, these modern technologies prove to be pivotal to today’s operations.

One key task the particle size analyzer performs is to continuously monitor ore fineness in the grinding circuit. It automatically measures particle size in the hydrocyclone overflow to enable efficient control of the grinding process.

Why is this so important? Several problems can occur when online data from an analyzer is not available, most importantly, the ore might not be ground finely enough to enable optimal mineral liberation in flotation. In this case, valuable mineral particles can’t be recovered and will be lost to tailings. can trigger sanding in the bank’s first flotation cells and, hence, reduce processing capacity. Furthermore, in the absence of online grinding control, there is a risk of overgrinding thus resulting in metal losses in fines, filter blockages and ultimately unnecessary grinding energy consumption. Since grinding accounts for the highest proportion of energy consumption in the metal production value chain, this should be avoided at all costs.

Similar to having a speedometer your car – it is critical if anything changes,” says Manu. ”It is difficult to control your car if you don’t know how fast you’re going, and that’s the main idea, that at all times, you know how your process is performing in real-time.” The same analogy can be extended further if we compare similarities between the cruise control system of a car and an Advanced Process Control (APC) system of the grinding process. Same way as the driver gives a setpoint for a desired car velocity, the process operator gives a setpoint to the desired flotation feed particle size and the APC system tries to maintain this particle size and to maximize grinding throughput. Similar to how today’s car manufacturers have a vision of self-driving cars, miners also are looking to the future and autonomous plants. Without accurate measurements of the state of the process, it is not possible to implement the current APC systems of today or to move towards autonomous plants of the future.

Metso utilizes in-house Performance Centers, which function as hubs for remote monitoring and digital services to collect and analyze data. With state-of-the-art facilities custom-built for remote collaboration, automated analytics and predictive recommendations, it allows our experts to identify and assess equipment performance. Customers are also privy to this instant information. Since the analyzers are connected to their control system, they can immediately view their own results.

Real-time elemental analysis is one of the most important online measurements for efficient flotation circuit control to achieve optimal metal recovery. Today, online elemental analyzers are widely used for optimizing various concentration processes such as copper, nickel, gold and spodumene flotation. To achieve optimal flotation recovery, the metal content in tailings must be monitored continuously and corrective actions – such as adjusting flotation bank mass-pull – must be carried out to prevent losing metal to tailings.

“In terms of measurement accuracy, we have the most accurate online elemental analyzer on the market,” states Juha. ”This gives operations the ability to optimize the flotation circuit to recover the highest levels of metals from the actual feed.”

For many of the measurement technologies available on the market today, this can be challenging. The metal content in tailings is very low, especially in precious metal flotation, and the situation will become even more drastic in the future due to declining ore grades. By using a properly maintained and calibrated online elemental analyzer, you can reduce metal losses to tailings and improve the overall recovery of the plant.

Numerous site managers and process engineering teams are realizing the significant impact that analyzers have on a mine's productivity and financial gains. So understandably, it is critical to maintain the equipment correctly. Even a slight decrease in accuracy or an unexpected breakdown can disrupt its capacity to provide precise measurements, thus leading to a lower return on investment.

Three key approaches to analyzer maintenance include:

“The Service Agreement is vital for us,” comments a Senior Process Specialist at a customer site. “The availability of the analyzer is critical, as we cannot run without it. It affects both our productivity and safety, and having external competent people working with us creates confidence.”

”We use the best available technologies in our analyzers, and we choose these technologies because they are robust and can be utilized in challenging and different conditions,” says Juha. ”Mine sites can be very dusty, and temperatures can range from extremely hot to frigidly cold, so it is important that the analyzer is treated with the care it requires. These are high technology products that need professional maintenance – otherwise, things can go wrong.”

It is simple: If the analyzer is not looked after, the accuracy suffers. When calibration is not maintained, this can begin a damaging cycle. Operators of the plant will stop trusting the measurement quality because it is not in line with the actual laboratory measurement, causing them to resort to conducting more manual assays.

”Plant operators may switch to old habits and run the plant according to the composite samples that are analyzed every shift,” says Juha. ”So instead of running on real-time plant data, they utilize manual data that has a delay factor. This will lead to suboptimal performance, and a significant amount of metal will be lost to tailings.”

Conducting a manual assay is not only time-consuming can involve delays between sampling and putting potential remedial actions into place, during which time the above-mentioned issues may have occurred. Although the initial investment in an analyzer system is significant, the system soon pays for itself in the form of increased efficiency, reduced losses, and higher recovery rates. The fast, accurate assaying of analyzers allows operations to react immediately to changes in the metallurgical performance while simultaneously monitoring the effect of operational actions in real-time. On top of that, running a laboratory on-site can be expensive and online analyzers can reduce the workload and costs associated with an onsite lab.

“That’s why we can guarantee the availability of the equipment with online monitoring and an LCS agreement,” says Manu. ”It will run with up to 95% availability or more, and it will be extremely accurate compared to the lab results. With manual laboratory testing, it could easily take a couple of days where there will be no information on how their equipment is performing, which could place them at a major financial disadvantage in comparison to other mines taking fuller advantage of this technology.”

In the mining industry today, it is difficult to ignore the increase in work rotations or personnel changes, which unfortunately leads to losses in essential know-how. There are numerous reasons for this, including the ageing of the existing experts and the lack of attraction of young professionals due to the growing number of opportunities available for working remotely.

“With this gap in expertise, it’s even more important that an expert is there to support the customers in finding a new person responsible for calibration or to provide calibrations remotely when needed,” says Juha. “This specific know-how is not the core expertise of the mining company itself, so naturally, it makes more sense to outsource the responsibility of the analyzer calibration to us.”

Another important KPI regarding analyzer performance and leveraging digitalization is availability. In addition to accuracy, there have been instances where customers, who have had an analyzer for several years, had sample streams that were not available for measurements due to blockages or issues with the sampling lines. This is where digital tools have a vital role to play.

“When we installed the Metrics system, it was obvious there were certain sample lines that tended to get blocked,” says Juha. “We discovered that by re-routing some of the sample lines and adding an automatic flushing system, we were able to reduce their unnecessary downtime. Improvements like this can be made solely thanks to identifying these issues quickly with this digital technology.”

As the mining industry accelerates its digitalization journey, taking advantage of live data 24/7, a partnership with your OEM will help you stay ahead of the curve whilst meeting your performance and sustainability targets. We believe that by changing the role of OEMs from suppliers to partnerships, this will pave the way for major improvements. Together, Life Cycle Services agreements and digital tools can be critical in securing the longevity and the value of the equipment as well as ensuring process performance.

“The customer will get more transparent actions from our partnership and if we can guarantee performance, availability and accuracy, the customer will always win,” says Manu. ”They get their equipment working better than before, which leads to increased plant control and greater recovery.”

Careful planning is crucial, as unplanned repairs can easily cost from four to even twelve times more than planned repairs. It is essential to identify problems before they occur, to plan repairs in such a way that the customer’s time and money are not wasted and to prevent unexpected component or equipment failures, as even small failures can affect the entire process.

”With preventive maintenance, we are able to stay ahead of planning and scheduling of visits and part changeouts,” says Juha. ”This agreement with the customer allows our experts to gain insights in their shutdown schedule, so we can conduct part changeout checkups on the equipment during the shutdown.”

Life Cycle Services takes our entire after-market portfolio and conveniently bundles them into customizable, easily manageable packages. Depending on the scale of your needs, packages are flexible and equipped to cover a single event or to span multiple years, measured against strict KPIs. The collaboration of business lines allows for synergies and knowledge sharing since our different experts work under one contract. This also leads to more visibility on all previous actions.

”Then of course, the device diagnostic information is also unbelievably valuable to us,” notes Juha. ”As an OEM, the data provides feedback, and shows us where our research and development need additional focus to develop even better products in the future.”

Metso offers a range of different analyzers to meet customer needs. Experts can advise on which one to choose, set up your system and devise the appropriate test protocols for you. Once it is up and running, analyzers provide continuous assaying of ore in real-time, helping to tackle the challenge of declining ore grades.

By leveraging digital tools and data-driven services, analyzers have higher availability, accuracy, sustainability and safety. This reduces manual labor and unnecessary downtime whilst increasing recovery and precious metal losses. With a Metso LCS contract also in place, equipment performance is guaranteed for years to come.

Original version of the article has been published in International Mining.