Overcoming bottlenecks - Time for the nextSTEP™?

Concentrator design has a large impact on the flow in production because oversizing in one area will push problems downstream. The challenge is to strike the right balance between equipment flow and recovery of concentrate ore grades.

One way to overcome bottlenecks is to include a consistent design factor throughout the engineering process. This requires solid knowledge of the ore, open and transparent cooperation and sharing of expectations between the mine owner, engineers and equipment suppliers. Setting the design criteria based on shared expectations and common ground enables the parties to design a solution with focus on total cost of ownership, rather than lowest capital investment.

“A consistent design factor on all equipment might mean a slightly larger initial investment. However, it is much more costly to shut down operations and replace undersized equipment at a later stage. The primary reason for focusing on the design factor in comminution is to accommodate periods of harder ore, where the circuit otherwise is designed to process at average rates,” says Dave Rose, Global Process Director for Concentrators at FLSmidth.

For instance, a copper comminution circuits in the range of 100,000 t/d typically have a design factor of 15 percent and this design factor often leads to a production of 115,000 t/d. Consequently, this creates bottlenecks elsewhere in the production line.

Keep it floating

To make sure that the design criteria meets the need of the specific mine - and that all equipment meet these criteria, too - FLSmidth has the advantage over most suppliers by being a full flow sheet provider.

“Since we develop, supply, install and maintain all the necessary equipment and workflow, our customers are sure that all equipment function well together and are sized according to the needs. To meet their needs, we continuously develop new equipment or make improvements on existing equipment, for example our new nextSTEP™ rotor/stator flotation device. Dewatering circuits are generally pretty forgiving on the performance if oversized, but are extremely unforgiving if undersized”, says Rose

Step-by-step plan

The balance between the percent solids, the head grade and the recovery grade is essential. Using too high a design factor in the flotation circuits can introduce other concerns, including recovery and concentration grade because of the change in retention time in the cells.

“While rougher flotation may have high grade and recovery, the cleaners may exhibit negative performance because of higher tonnage rates or higher grade feeding into the cleaners than what was designed for. The volumetric balance is very important. We regularly visit plants where the ore head grade is high and a properly designed flotation circuit is underperforming because the ore does not match the design criteria provided for the circuit. The big challenge with higher head grade is not overloading the cleaner circuits. Concentrate grade may be better but the recovery will be lower, as there are higher value minerals lost in the circuit,” he says.

The best design is made by considering various scenarios in a step-by-step manner through the flowsheet, starting with the comminution circuit. The design has to combine the ore and mineralogy characteristics with the client’s expectations.

The next step in the process is recovery, which has to include consideration of the ore grade, recovery variance, as well as operational conditions, such as slurry, density, reagent addition, etc. Next to consider is the variation in recovery and feed rates to determine the best option for sizing of the dewatering equipment.

Key benefits of the nextSTEP™ rotor/stator**

• Significant improvement in both metallurgical performance and energy efficiency

• Lowest operating power of any mechanical flotation mechanism on the market

• Dramatic improvements in attachment rates, which translates into significant recovery increases

• Better wear distribution increases product lifecycle and improve total cost of ownership

• Designed to be retrofitted in all forced air machines, regardless of make or model

Lowest power consumption flotation technology on the market

The nextSTEP rotor/stator from FLSmidth reduces power requirements by 15-40 percent and has a better wear distribution, which therefore increases the life span and reduces the total cost of ownership. With reduced OPEX through energy efficiency and significantly improvement of recovery rates and concentration grades, the nextSTEP™ rotor/stator is a step change in flotation.

It is possible to retrofit the nextSTEP rotor/stator into existing flotation cells up to 660m3. The conversion process is simple, low risk, for all makes and models, and proven already with a large number of successfully completed retrofits for flotation cells ranging in size from 5m3 to 250m3.


Dave Rose, Global Process Director, Concentrators


From pit to plant

Fast start-up, reliable operations and the potential to increase pit-to-plant productivity are some of the likely customer benefits following FLSmidth’s recent acquisition of part of Sandvik Mining Systems.

With the recently finalised acquisition of the Sandvik Mining Systems projects business, FLSmidth has become a single technology provider of full flowsheet technology to the mining industry, with the ability to deliver fast start-up and reliable operations to customers.

The acquisition means a wider range of the customer supply chain, from primary crushing to tailings handling, can be covered by FLSmidth. However, it is more than just technologies; additional expertise for continuous surface mining, in-pit crushing and conveying (IPCC), and minerals material-handling technology is now available to the customer through the expanded FLSmidth offering.  


 “Our customers will benefit from the most comprehensive combined product portfolio in the industry, and they will be able to increase the productivity of their complete ‘pit to plant’. By knowing what will be coming into processing, we can help bridge the gap between pit operations and the processing plant, thereby increasing overall process efficiency,” says Paul Emerson, Global Product Director for FLSmidth’s Mining Material Handlings systems.

A single supplier optimises productivity

There are numerous advantages in choosing a single supplier. A key element is that maintenance and technical support can be streamlined, which can increase time and cost efficiency. For instance, should a problem arise and the root cause is difficult to identify, it is a clear advantage to only have to enter into dialogue with a single supplier, who can effectively deal with all issues, rather than having to engage with a host of different suppliers. The daily benefits include more clearly defined responsibilities, reduced total cost of ownership and improved productivity.  

“In the past decade, mining corporations have gone to great lengths to reduce CAPEX, but currently we see focus changing to total cost of ownership. Especially on greenfield projects, In-Pit Crushing and Conveying can reduce the total cost of ownership as it reduces OPEX and truck costs. Ignoring the long-term OPEX is detrimental in the new norm for the mining sector,” says Emerson.

Another benefit for miners is that a full flowsheet facilitates digital access to all key processes and equipment. “We can now digitalise the entire supply chain to provide pro-active condition monitoring and data collection, identifying damage or wear ahead of any failure, even on mobile IPCC and stacking equipment. The data can be benchmarked with best practise and used to optimise the production. We keep investing in being on the forefront of IPCC systems and Dry Tailing Stacking technologies going forward. This will allow customers to reduce total cost of ownership and increase throughput in order to increase their productivity,” says Emerson.


Paul Emerson, Global Product Director


Thickener upgrade boosts performance

Reduced flocculant consumption and improved operational performance are the results of a thickener upgrade at a large Australian gold mine. 

A leach feed thickener was creating a bottleneck in a gold mine in Western Australia. The installed thickener was a preinstalled ‘off-the-shelf’ product, neither supplied nor installed by FLSmidth. As the on-site maintenance contractor, the client asked FLSmidth’s team of specialists to assess the performance and offer a solution to improve productivity and overall performance. As a result, FLSmidth’s engineers identified several improvements to the thickener’s control set-up. 

"The customer realised their feed system was under-sized and hampered by air entrainment. The density-reliant dilution system meant that the feed stream was not being diluted, resulting in high flocculant consumption, poor overflow quality and lower than desired underflow density," explains Dane Smith, Dewatering Product Manager at FLSmidth.  


Following test work, a process review and structural analysis of the bridge and thickener tank, the FLSmidth team recommended a combination of the E-DUC® feed dilution technology and the E-Volute™ feedwell. The E-DUC® system uses feed stream momentum to induce large volumes of feed dilution prior to the feedwell, thus optimising flocculation due to improved mixing profiles and residence times.

The E-Volute feedwell is characterised by excellent feed stream energy dissipation, optimal mixing energy and shear profiles. Subsequently, it promotes even feed distribution into the thickener with minimal floccule breakage, therefore improving the overall sedimentation performance.

Reduced installation time

Specialists at the FLSmidth Supercentre in Perth completed the project from on-site test work and inspection, to process and mechanical design, fabrication of all components, installation, and finally, commissioning. No other Original Equipment Manufacturer (OEM) has the ability to provide such a breadth and depth of service.

“Having control of the project meant we could keep to the required tight delivery schedule, while remaining in control of quality and planning on-site. This ability helped to shave three full shifts off the installation, allowing the site to return to full production far earlier than they had thought possible,” says Smith.


The results are convincing

Initial data analysis shows a reduction in flocculant dose of approximately 34 percent and an increase in underflow density by approximately 2 wt. percent during the first two months.

As the plant continues to optimise the new system under FLSmidth’s recommended control setup, flocculant savings are maintained and underflow densities have increased up to 8 percentage points from 48 wt. percent to 56 wt. percent (6 percent on average), limited only by the rake drive torque.

In addition to the achieved flocculant savings, the increase in leach feed density reduced total volumes reporting to the CIL, the minerals recovery process, by around 16.5 percent. Decreasing cyanide and lime requirements while significantly increasing available leach residence time, promoting gold recovery.

The results are such that the 34m leach feed thickener with FLSmidth technology is producing higher densities than the 44m tailings thickener with non-FLSmidth OEM technology.


Dane Smith, Technical Advisor, Dewatering


Positive sense of mining industry 'pulse' experienced at SME Conference

The 2018 Society of Mining, Metallurgy and Exploration (SME) Annual Conference & Expo provided a forum for more than 6,000 industry professionals from across the world to share innovative ideas, best practices and cutting-edge research in more than 120 technical sessions along with an expansive marketplace of more than 550 exhibiting companies, including FLSmidth.


The SME conference is one of the most important regional opportunities to network with industry customers and suppliers. It also gives a good sense of our competitor’s current positions in the marketplace. According to Joe Dziedzina, FLSmidth Product Manager, HPGR “Due to breadth of attendee types, the event helps provide a real feel for the pulse of the industry.” During the week, booth presence was active and several potential projects were identified.

FLSmidth was event sponsor
 FLSmidth served as sponsor for the debate session, which included a several speeches and a panel discussion on the importance of a diverse and inclusive workplace as key driver behind productivity, profitability, emerging innovations and technology advancement in mining.

Demonstrating industry leadership at SME Technical Sessions
Several technical sessions took place during SME, wherein the mining industry's best and brightest gathered to share their knowledge, experience and expertise. The session topics covered some of the most current, relevant research in the industry, and illustrated innovative solutions to many common mining challenges.  

On behalf of FLSmidth, Dave Rose served as a session chair on the topic of plant design. During the session, a white paper co-authored by Dave was presented by Jesus Gonzales from Pena Colorada, a close customer of FLSmidth. The paper summarised years of collaboration on throughput expansion, which resulted in the addition of a second comminution circuit at the Pena site.

Dave states, “This site is an important project for FLSmidth. In the many years of working closely with this client, we have installed several pieces of equipment during this expansion, including a SAG mill, ball mill, cone crusher and gyratory crusher, required for the throughput expansion. In addition, we added one new thickener and retrofitted four existing thickeners at the site to accommodate the extra tailings generated by the higher throughput.” 


Leadership in developing large-scale tailings filtration

Todd Wisdom, Director Process Line Tailings Systems, presented on Large-Scale Filtration Demonstration Plant. The paper highlighted FLSmidth’s continuing leadership in developing large-scale tailings filtration a viable economic and technical option for large scale mines. 

“Through recent advancements in filtration dewatering technology and scale, we are making filtered tailings economically viable for large mines.  In presenting these results at SME, our goal was to demonstrate FLSmidth’s industry leadership in improving the sustainability of mining, which is has been increasingly important in the eyes of the general public,” says Todd.

Productivity in thin air

Peruvian mining company Volcan Compañía Minera installs paste thickeners and doubles its capacity in six months.

In the thin air of Cerro de Pasco, high in the Peruvian Andes Mountains, Volcan Compañía Minera’s processing plant more than doubled throughput in six months. The plant now exceeds its original design capacity of 2,500 tonnes a day – and can process as much as 3,000 tonnes. However, half a year earlier, the oxide plant was underperforming as it only managed a throughput of between 900 and 1,200 tonnes of gold and silver-bearing oxide ore per day.

Juan Manuel del Aguila, project engineer at Volcan, and his colleague Luis Loaiza collaborated with FLSmidth’s team in Peru to find a solution to improve the process of recovering silver via cyanide. Volcan’s team of engineers travelled to Salt Lake City, Utah to perform further tests at FLSmidth’s facilities.


“The initial tests in Salt Lake City resulted in a large filtering area, but we also carried out parallel tests to explore other options. It turned out that we could meet the objectives with the EIMCO® Deep Cone® Paste Thickeners. We returned with these results and carried out onsite tests at Cerro de Pasco,” says Manual del Aguila.

 “Our engineers installed a pilot thickener plant at the site and after twenty days of testing, we found that it would increase the tonnage at the plant. This allowed Volcan to meet their capacity needs. A solution that required less time and less capital than applying additional filters,” says Walter Gamero, Senior Process Engineer at FLSmidth, Peru.

Cooperation fast-track the process
Volcan awarded FLSmidth an EPC contract to supply two Deep Cone Paste Thickeners, including the required tanks, piping, pumps valves instrumentation,  control boards, cables, motors and control system . Only a week after operation, the Volcan oxide plant exceeded its original design capacity of 2,500 tonnes a day.

“We are not limited to just supplying the equipment with a mechanical guarantee but can also apply business models providing guarantees on the performance of the equipment in terms of volumes, availability.” says Gamero. By excessive cooperation between Volcan and FLSmidth, the process was fast-tracked and a success.

Leading test facilities

To find the optimal solution for Volcan Compañía Minera’s processing plant, engineers from Cerro de Pasco travelled to FLSmidth’s R&D centre and test facilities in Salt Lake City, USA. Here, FLSmidth offers leading test expertise in precious metals, base metals, and industrial metals.

The facilities include crushing, grinding (including ultra-fine grinding capabilities), gravity separation, hydrometallurgy (ambient and autoclave technology), column leaching and flotation. Flotation equipment includes mechanical test cells from 50 grams to 15,000 grams capacity. The laboratory also offers in-plant consultation services and plant auditing.


Walter Gamero, Process Engineer


Challenge: Copper in Armenia

FLSmidth is staying on to help a mine in Armenia faced with accusations of causing environmental and social impacts. Active involvement has a greater long-term impact on sustainability than abandoning a site and leaving the problems with the client and the local community.

In 2013, FLSmidth was hired to engineer and provide equipment for a mineral processing facility for a copper mine in Lori province near Teghout in northern Armenia, partly funded by Danish institutions. The equipment supplied for the project was of the highest standard regarding environmental impacts. Local residents and non-governmental organisations raised issues about the construction and operation of the mine, mainly with regard to pollution of rivers; the felling of forests that are home to endangered species and accusations of exploitation of small farmers whose land was expropriated under allegedly questionable circumstances.

In 2017, this came to a head when a Danish non-governmental organisation levied unsubstantiated accusations against the mine operator and FLSmidth. This led to public scrutiny of those involved and caused the withdrawal of the financial guarantee, although this did not contribute to resolution of the concerns. As a supplier to the project, FLSmidth chose a rather different approach. It was well understood from the beginning that pulling out of the project meant leaving it for the customer and the locals to deal with the problems alone. FLSmidth refused to do so, even though the issue under scrutiny (mine and tailings facility) were not in scope of FLSmidth.

1 Teghout Plant (1).jpg

“We decided to stay in the area and attempt to make a positive difference by applying our expertise. We believe you can make more of an impact by being present on site, as long as there is trust in the relationship and the aim to solve the problems at hand. We are in regular dialogue with our customer on how best to assist them with their challenges and thus make a positive difference in the area,” said Manfred Shaffer, executive vice president of the minerals division.


As supplier to the project, FLSmidth expects that the customer will take the necessary steps to address and improve conditions surrounding the mine and processing plant. By leveraging the relationship with the customer, a dialogue was immediately established, by the project manager and escalated within the organisation. This allowed proper communication channels to be established at the right levels to review options for overcoming the challenge.

Furthermore, FLSmidth engaged some of the financial parties to identify what their concerns were, prior to their withdrawal. This allowed for a full understanding of the stakeholder expectations. The unsubstantiated claims were discussed directly with the non-governmental organisation and the journalist who levied the accusations. FLSmidth ‘s role was made clear, as well as where the legal responsibilities of each party lie, and how FLSmidth went beyond the legal boundaries to address and support a resolution of the issues.

This was a very complex situation, where national laws and norms were not aligned with international performance standards; where the way of operating a mine and processing plant in the country was called into question and with confusion as to what the actual individual responsibilities of each stakeholder were. We are committed to continually raising the standards of sustainable development in our field, and we believe that we can push the development in the right direction through dialogue
— Manfred Shaffer, Executive Vice President of the minerals division.


FLSmidth: delivered design, machinery and supervised the construction of the mine facilities, all above ground

Finance: Denmark’s Export Credit Agency (EKF) provided the financial guarantee, and The Danish pension fund, PensionDanmark, partly provided the financing with DKK 350m by extending a loan arranged by a French bank to a Russian bank for further on lending.

Major risks: An identified potential risk to the customer is that the nearby dam, built to stem the flow of liquid waste from the mine, might collapse should a major earthquake strike the area. In 2016, the World Bank published a study on the mineral sector in Armenia, showing that none of the 21 tailings dams reviewed had the appropriate design or management for a seismically active area. Teghout CJSC is currently reviewing the risks and solutions based on the International Commission on Large Dams standards, and has committed itself financially to implement the proposed solution.



  • 2008: Order for the mills and grinding area, with associated plant engineering
  • 2011: FLSmidth receives order for the balance of equipment and plant engineering
  • 2014: All engineering of the plant was done in accordance to local codes and standards and put into operation
  • 2017: Financing was withdrawn

Read FLSmidth's 2017 Sustainability Report


Alexander Campbell, Group Sustainability Manager, ARC@FLSmidth.com

Finding the right sound in your SAG mill

By analysing the sound and other process parameters, SAGwise™ adjusts mill load and decreases steel-on-steel impact, resulting in less energy consumption and increased production.

Operating a SAG mill is a costly affair. Yet, a SAG mill is most costly as when it stand still. Therefore, being able to predict the right mill load optimises the output and minimise repairs and standstills is of utmost importance.


Today, experienced plant operators depend on the personnel close to the SAG mill listening to the mill load for critical steel-on-steel impacts. If critical impacts occur, they manually adjust the SAG mill load to make the mill run smoothly. Though this is a qualified way of handling critical impacts, a new digital solution utilises acoustics sensors to reduce downtime and increase the mill’s reliability and productivity.

Acoustic sensors optimise SAG mill operation

The new FLSmidth SAGwise™ process-control uses acoustic sensors and proprietary process control software to predict and adjust the SAG mill operation according to impacts on the mill and other main process variables. The acoustic sensors ensure regular and accurate adjustments to mill loading.

The solution employs state-of-the-art process-control technologies to reduce critical impacts to the desired targets; stabilising and optimising the SAG mill’s operation. The solution embeds multiple process-control technologies, modelling both the process and the human operators.

SAG mill animation image acoustic sensors.jpg

“Within seconds, SAGwise can analyse audio frequencies as well as on board power usage, mill weight and bearing pressure. It can then automatically take corrective action if needed and adjust parameters such as the mill ore feed rate, mill speed or slurry density. Where an operator might make adjustments every few minutes, this solution can make less drastic adjustments more frequently, down to every 20 seconds or less,” says King Becerra, Global Product Line Manager for Automation Process Optimisation.

Test results show that these adjustments reduce damage to the liners by up to 40 percent. This means less unscheduled downtime and increase in production.

“The one sound operators do not want to hear is the sound of the mills standing still. A gold-processing plant, I visited recently valued their SAG mill downtime at US$ 130,000 per hour, so extending the life and availability of mill liners is crucial to them. The reduced damage improves the mills availability and minimises the down time. This can translate to literally millions more tonnes of ore milled,” says Jack Meegan, Global Product Line Manager for Mill Liners.

ROI in six months
“We want to make sure that our customers are getting more value from their liners as well as from their media. With many mines using $10 million or more on liners per year and 3 or 4 times this cost in terms of grinding media, the savings can be huge,” says Meegan.

Test results also show a reduced energy consumption of up to six percent. Considering that mills are the largest power consumer in minerals processing, this is quite significant. Furthermore, the new solution resulted in a six percent production increase and reduced process variability by up to 30 percent. With these savings, SAGwise can pay for itself within six months or less.


How does it work

Audio sensors close to the SAG mill listen for undesirable high-energy critical impacts. Intelligent software analyses the patterns and adjust feed, speed and pulp density for optimal efficiency to decrease power usage, reduce critical impacts and preserve liner life.


  • Increase liner life
  • Decrease critical impact by up to 45%
  • Up to 6% reduction in grinding specific power consumption
  • Up to 30% reduction in process variability
  • Minimised downtime
  • Reduce ball consumption

Learn more about SAGwise at our product page


King Becerra, Gobal Product Line Manager, Process Optimisation,  Automation