Tag Archives: mineral processing

Derrick offers higher screening productivity in confined spaces with the SuperStack

Comminution of minerals, Mineral processing, Mining equipment, Mining services, , , , , , ,

Derrick Corporation has introduced its new 8-deck SuperStack® vibratory screening machine, which, the company says, offers two-and-a-half-to-three-times the capacity of its precursor, the 5-deck Stack Sizer®.

With its eight decks operating in parallel, combined with a 30-35% increase in effective screening width per deck, the SuperStack achieves significantly higher production capacity with only a modest increase in footprint, according to Derrick.

While the 5-deck Stack Sizer is equivalent to a 5 m wide by 1.5 m long screen, the 1.42 m wide SuperStack is equivalent to a 11 x 1.5 m screen, the company said, adding that all screen frames are coated with abrasion-resistant urethane for extended service.

More effective use of screen area and increased capacity results from the front-to-back screen tensioning system, which tensions the panel in the direction of flow rather than side to side. In addition to increasing productivity, the tensioning system reduces screen panel changing time by 80-90% compared with side-to-side tensioning, according to Derrick.

Derrick Polyweb® urethane screen panels with 150 or 180 micron slotted openings are available for the SuperStack and an optional repulp spray system introduces free water into replaceable rubber wash troughs to help undersize material pass through screen openings.

Dual oversize launders (one per side) and a single undersize launder eliminate the need for a large hopper, which minimises height requirements. Each feeder additionally has a removable front cover to facilitate maintenance and debris removal, while custom designed inlet pipe configurations are available from Derrick, if needed, to meet equipment layout requirements.

The Flo-Divider™, which equalises flow from the feed source to each deck, meanwhile, is available in a number of discharge outlet configurations from two-way to 16-way.

Dual vibratory motors are positioned directly over the upper screen frame to deliver linear vibratory motion to all eight screen decks, with the motors having an internal oil lubrication system that eliminates the need for a separate lubrication system, while providing long-term maintenance-free operation and low sound production.

Todd Burchett, Vice President – Mining and Industrial Division, Derrick, said the SuperStack is a highly efficient means of achieving major production increases within a comparatively small footprint.

“Consequently, we expect the SuperStack to fill the need for higher productivity in facilities where space is limited.”

Mitch Derrick, Derrick CEO, said the innovative solution offers over twice the capacity of traditional units in a similar footprint, “significantly reducing both the upfront installation costs and ongoing operating and maintenance costs”.

Dan Cook of American Silica, which has already experienced the Superstack, said his company had seen a “vast improvement in quality and efficiency”. He was especially pleased with the ease of changing the SuperStack screen panels, according to Derrick. “The front-to-back tensioning makes screen changes faster than the 5-deck.”

Noting the productivity improvement, Cook said plant capacity had increased by about 20%. “We’ve gone from 700 tons (635 t) per shift to 950 tons per shift! And we believe it can handle more than what it’s rated for. We’re really pleased with the 8-deck!” he concluded.

Earlier this year, Derrick said Metalloinvest was planning to use the new 8-deck SuperStack at the Mikhailovsky mine, in Russia, as part of the company’s project to improve the quality of the operation’s iron ore concentrate.

FLSmidth to boost plant efficiency with SmartCyclone system

Automation, Comminution of minerals, Equipment maintenance, Mineral processing, Mining equipment, Mining maintenance, Mining services, , , ,

With process plant optimisation techniques becoming a necessity for mines looking to maximise their operating performance by keeping costs low, throughput high and downtime to a minimum, FLSmidth has devised an automated monitoring and control solution for reducing cyclone-related process deviations.

The SmartCyclone™ system delivers in all three areas for cyclone circuits, according to the company, improving cyclone overflow particle size distribution, predicting and controling cyclone maintenance schedules, and optimising closed-circuit grinding processes.

FLSmidth said: “This equates to monitoring the performance of individual cyclones within a circuit in real time, preventing unplanned breakdowns from occurring and monitoring wear rates while ensuring the cyclones are operating optimally at all times. This translates into higher efficiencies in the plant and ultimately, higher profitability.”

The SmartCyclone closed circuit grinding optimisation system combines a variety of FLSmidth patented technologies, including the FLSmidth Krebs SmartCyclone wear detection sensor technology and the Krebs’ patented roping sensor technology (with patent-pending wireless controller system). This technology immediately identifies if a cyclone is malfunctioning, the company said.

The closed circuit grinding optimisation system also incorporates FLSmidth’s ECS/ProcessExpert® process control software with a new patent-pending SmartWear™ cyclone maintenance algorithm.

One of the largest benefits associated with this software is the ability to develop a uniform operation strategy that outlines the best way to run the plant, according to FLSmidth. “Once this strategy has been established, the necessity to train new operators is reduced.”

Reducing or eliminating manual operation, which decreases the potential for human error, is also one of the overarching benefits of SmartCyclone, the company says.

FLSmidth has more recently enhanced its Krebs SmartCyclone system with wireless technology that
enhances installation by eliminating the need for individual nodes and the interconnecting cables between the sensors and nodes and associated controllers.

It uses a central wireless controller that can handle up to 16 sensors per unit; providing real-time wireless detection and communication of roping and/or wear data. The new wireless controller unit is a handheld device that can be removed from its docking/charging station to sync the individual sensors. Once removed, it goes into battery-power mode and the user can walk to a desired sensor, activate it with a magnet, trigger and set the necessary operating parameters.

Multotec-manufactured SAG mill trommel screens beating the competition

Comminution of minerals, Equipment maintenance, Mineral processing, Mining equipment, Mining services, , ,

With mining companies looking to improve productivity and reduce downtime in the process plant, Multotec is promoting the use of its locally manufactured SAG mill trommel screens as a viable alternative to vibrating screens in SAG mill scalping applications.

“Many designers and mill operators believe that the benefits of simplicity and the ability to handle throughputs in excess of 3,500 t/h of solids make trommels the preferred equipment for this application,” the company said.

A key component ensuring optimal performance of SAG mill trommels is the screen panel, which enables this equipment to classify large volumes of mill product, according to Francois Fouche, Senior Screening Specialist at Multotec.

The company has developed a special range of rubber compounds used to manufacture the compression moulded rubber screen panels that are considered the highest wearing items in the trommel.

“We have achieved excellent results from our compression moulded screen panels with wear life extending over six months in 4,500 t/h hour SAG mill applications,” Fouche stated.
With nearly four decades of experience supplying locally manufactured trommel screens and, Multotec, today, has the process capability to size SAG mill trommel screens with diameters up to 5.5 m, it said.

“The company also designs its trommel screens to suit each customer’s unique requirements and confidently offers process and mechanical guarantees,” the company said.

Fouche said: “Considering the size and complexity of large SAG mill trommel frames, Multotec is able to apply the latest finite element analysis techniques during the design phase to ensure we reduce fatigue stresses and ensure structural integrity.”

Multotec, given the arduous duty, covers all frame surfaces exposed to the milled product with a wear resistant material, typically rubber.

Fouche said the operational performance of a SAG mill trommel is another key consideration for Multotec: “As adequate retention time is required for the efficient removal of the fine fraction, we need to reduce the high velocity of the slurry that exits SAG mills.

“We are able to achieve this with various configurations of weir bars. The design of a set of scrolls is an integral part of the design process as these regulate the flow of solids through the trommel screen.”

Multotec has supplied a number of trommel screens for 38-40-ft (11.6-12.2 m) SAG mills that required 500-600 mm high weir bars to create sufficient retention time. It can also supply a range of rubber shell plates and lifter bars to protect the SAG mill trunnion against wear.

“Providing long term customer support is one of the major advantages that Multotec offers,” Fouche says. “Our experienced competent field service crews maintain the screening media and provide condition monitoring on the trommels.”

The Multotec field service maintenance crews can also focus on wear rate indication and monitor the wear resistant lining of the steel structure, and in doing so provide a complete maintenance solution.

Metso and Outotec tie-up wins backing at EGM

Comminution of minerals, Mineral processing, Mining mergers and acquisitions, , , ,

Metso says its Extraordinary General Meeting (EGM) has seen the Board of Directors’ partial demerger plan and combination with Outotec approved.

The decisions of the EGM will become effective as of the registration of the completion of the partial demerger, which is expected to take place in the June quarter of 2020, subject to the statutory creditor hearing process and receipt of all required regulatory and other approvals, including competition clearances.

The combination of Metso Minerals and Outotec is highly complementary and will create a unique company in the industry, according to the two companies. “Metso Outotec will leverage the strengths of both companies, including technology and R&D, product and process excellence, scale and global service offering footprint. The combination will deliver significant benefits to all stakeholders,” they said.

As part of the deal, Metso Flow Control, which was recently split off from the Metso Minerals division, will become a pure-play listed entity under the name of Neles.

Pursuant to the demerger plan, all such assets, rights, debts and liabilities of Metso which relate to, or primarily serve, Metso’s Minerals business will transfer, without liquidation of Metso, to Outotec.

The planned combination received approval from the Finnish Financial Supervisory Authority earlier this month.

Outotec celebrates 70 years of technology innovation at Pori ORC

Base metals, Energy minerals, Environmental, Metallurgy, Mineral processing, Mining equipment, Mining industry recognition, Mining services, Precious metals, Sustainable mining, Water management, , , , , , ,

Outotec is, this week, celebrating 70 years of sustainable technology development at its Outotec Research Centre (ORC) in Pori, Finland.

The ORC in Pori is unique in the industry, according to the company, with its expertise in the minerals and metals processing value chain ranging from ores to finished metals and recycling.

The centre was established in 1949 and, since then, has been a part of the company’s long-term research and development strategy. The company is holding a two-day seminar to celebrate 70 years of process development on October 15–16, with speakers including leading researchers, professors and industrial influencers.

One of several cutting-edge technologies developed at the ORC is Outotec Flash Smelting, which is still one of the world’s most commonly used processes to produce primary copper and nickel. This innovation was developed at the ORC at the end of 1940s.

The centre’s laboratories conduct tests on raw materials for Outotec’s customers and the related production processes. Current testing capabilities include nine laboratories and pilot plants, with, annually, some 200 research projects conducted, and more than 250,000 samples analysed.

Outotec said: “There is a genuine need for continuous development of processes since ore deposits are becoming leaner in grade and more difficult to utilise. The conventional methods are often insufficient to make them financially viable. Outotec’s research centre in Pori supports customers in selecting and, if necessary, developing new solutions for the efficient and environmentally sustainable extraction of valuable minerals from raw materials.”

The company said it can take decades for a completely new technology to establish itself in the market, but once the technology platform is developed, new applications may quickly be found. This has happened to cobalt and lithium processing technologies in recent years with the electrification of transport, it said.

Jarkko Partinen, Vice President, Technology and R&D at the ORC, said the cobalt extraction technology developed in Pori back in the 1960s is, today, gaining in importance due to the advent of electric transport.

“Thanks to our continuous research and development work, we are able to offer customers new and efficient ways of processing materials such as battery chemicals,” he added.

Kalle Härkki, Head of Outotec’s Metals, Energy & Water business area, said Outotec’s customers each face unique challenges and it is the company’s job to create solutions that help them succeed.

“We are proud of our process and technology expertise, and having our own research centre is a competitive strength,” he said. “ORC has been characterised by research into environmental protection, the circular economy, and resource efficiency before any of these topics became mainstream. One of the earliest studies, which dates back to 1951 and would nowadays be linked to the circular economy, examined useful applications for sulphur gas roasting residues.”

ORC employs 180 research and development professionals, 45 of which are process and technology development engineers, half of whom hold a doctorate level degree. There is a dedicated group working in modelling and digitalising process expertise.

The laboratories employ more than 100 professionals most of them working in three shifts specialised in building and maintaining test rigs and equipment, conducting the test work planned by the process development engineers, and analysing samples taken from the tests.

In 2018, the ORC welcomed more than 1,300 visitors, the vast majority of which were customers, researchers and people attending training.

Canada Cobalt looks for vertical integration with PolyMet Resources deal

Base metals, Energy minerals, Environmental, Metallurgy, Mineral processing, Mining mergers and acquisitions, Mining services, Precious metals, , , , , , , , , ,

Canada Cobalt Works has widened its processing options for both its Castle and Beaver projects, in the Cobalt Camp of northern Ontario, Canada, with the acquisition of a permitted and operating mineral and precious metal processing facility.

The company has signed a letter of intent to acquire the assets of PolyMet Resources Inc, owner of ISO-certified PolyMet Labs and the Cobalt Camp’s only permitted and operating mineral and precious metal processing facility, it said.

The C$650,000 ($491,861) transaction, expected to be made up of cash and shares, provides the company with “multiple immediate and long-term advantages”, it said. This includes a high capacity bullion melting furnace to pour payable silver and gold doré bars. The 23,400 sq.ft (2,174 sq.m) facility has sampling and analytical capabilities and can also host the company’s proprietary Re-2OX Process for environmentally-friendly extraction of cobalt, precious and base metals, it said.

Re-2OX skips the normal smelting process to create battery-grade cobalt sulphate, according to Canada Cobalt Works, with the company earlier this year saying it planned to submit a patent application to protect the technology.

The transaction will see the lab and mineral processing facility become the new headquarters of Canada Cobalt. This facility is located in the town of Cobalt, immediately adjacent to a rail line and just a short distance from the company’s Castle mine and Beaver properties.

The company said: “This well-established sampling and analytical facility, specialising in high-grade mineralisation, provides commercial assaying, crushing, screening, grinding, bulk sampling, upgrading and smelting services all in one location, driving multiple revenue streams at a time when gold prices in Canadian dollars have hit new record highs.”

According to the company, PolyMet has demonstrated that in an eight-hour shift, it can pour up to 10 doré silver bars of 1,000 oz each (90% to 95% fine).

“PolyMet is currently making inroads into the potentially lucrative e-waste business that can be leveraged through Canada Cobalt, its extensive relationships and its Re-2OX Process,” Canada Cobalt said. “Material from mixed computer boards is being processed through the facility’s shredder and ball mill to recover precious and base metals.”

Frank Basa, President and CEO of Canada Cobalt, said: “This deal builds dramatically on Canada Cobalt’s current competitive advantages and opportunities – technological, on the ground and underground – in a rejuvenated silver-cobalt district recognised as the birthplace of Canadian hard-rock mining.

“With such a unique and fully operational facility in the town of Cobalt, so close to the Castle mine and other properties, Canada Cobalt achieves a key goal of becoming a vertically integrated leader in Canada’s silver-cobalt heartland while it also exploits a powerful new cycle in precious metals.”

Gino Chitaroni, Majority Owner of PolyMet Resources, said: “We see some really exciting synergies here. Canada Cobalt’s track record of success in this district made them the perfect fit to take the PolyMet Lab and facility to the next level while I remain involved to assist Canada Cobalt from an operational standpoint.”

He continued: “Bullion pouring, bulk sampling, commercial assaying and e-waste are PolyMet’s four key immediate profit centres that merge with Canada Cobalt, creating powerful new synergies. Hosting Re-2OX and accelerating the development of such a unique and environmentally friendly process at this facility is a major coup for the town of Cobalt and the broader district.”

Metso Outotec planned combination wins Finnish FSA approval

Bulk handling, Comminution of minerals, Equipment maintenance, IoT, Mineral processing, Mining mergers and acquisitions, Mining services, Water management, , , , ,

The planned combination of Metso and Outotec has received approval from the Finnish Financial Supervisory Authority, the two companies have reported.

The approval is tied to the Finnish language demerger prospectus relating to the combination of Outotec and Metso.

Outotec and Metso announced on July 4, that the boards of directors of Outotec and Metso had approved a combination agreement and a demerger plan that would see Metso Outotec Corp created.

As part of the deal, Metso Flow Control, which was recently split off from the Metso Minerals division, will become a pure-play listed entity under the name of Neles.

The combination of Metso Minerals and Outotec is highly complementary and will create a unique company in the industry, according to the two companies. “Metso Outotec will leverage the strengths of both companies, including technology and R&D, product and process excellence, scale and global service offering footprint. The combination will deliver significant benefits to all stakeholders,” they said.

An extraordinary general meeting of Outotec and Metso shareholders was expected to convene on October 29 to approve the demerger plan, with the registration of the completion of the demerger with the trade register maintained by the Finnish Patent and Registration Office expected to take place in the June quarter of 2020, subject to other approvals.

Apron feeders: the material handling workhorses

Mineral processing, Mining equipment, Mining maintenance, Mining techniques, , , , , ,

Following the publication of the International Mining October issue and, more specifically, the annual in-pit crushing and conveying feature, we have taken a closer look at one of the core elements that makes up these systems, apron feeders.

In mining, apron feeders play a major role in ensuring smooth operations and increasing uptime. They are very diverse in their application within a mineral processing circuit; however, their full capabilities are not widely known throughout the industry leading to many raised questions.

Martin Yester, Global Product Support of Bulk Products at Metso, has answered some of the more important ones.

What is an apron feeder and when should it be used?

In simple terms, an apron feeder (also known as a pan feeder) is a mechanical type of feeder used in material handing operations to transfer (feed) material to other equipment or extract material (ore/rock) from storage stockpiles, bins or hoppers at a controlled rate of speed.

These feeders can be used in a variety of applications in primary, secondary and tertiary (reclaiming) operations.

Apron feeders are the preferred feeder for several reasons. Some of these are:

  • Aprons provide better feed control to prevent material feeding in downstream equipment from choking;
  • They can absorb the shock of loading material directly onto the feeder with a shallow bed (the impact coming down on the feeder when the material is dumped is great); and
  • Apron feeders can reclaim a variety of dry or wet materials of various sizes at a uniform rate, with this flexibility applied in many applications.

What are the advantages of using a tractor chain style apron feeder?

A tractor chain style apron feeder refers to the undercarriage chain, rollers and tail wheels that are also used in bulldozers and excavators. This style of feeder dominates the market in industries where users require a feeder that can extract materials of varying characteristics. Polyurethane seals in the chain prevent abrasive materials from entering the internal pin and bushing, which reduces wear and extends equipment life in comparison with a dry chain style. Tractor chain style apron feeders also create less noise pollution for quieter operation. The links of the chain are heat treated, which results in an increased service life.

Overall, the benefits include increased reliability, fewer spare parts, less maintenance and better feed control. In return, these benefits lead to more productivity with minimal bottlenecks within any mineral processing circuit.

Can apron feeders be installed on an incline?

The common belief about apron feeders is that they must be installed horizontally. Well, contrary to popular belief they can be installed on an incline! There are many added benefits and capabilities that come from this. Less space is needed overall when installing an apron feeder on an incline – not only does the inclination limit floor space, the height of the receiving hopper can also be reduced. Inclined apron feeders are more forgiving when it comes to larger lumps of material and, overall, will increase volume in the hopper and reduce the cycle time of the haul trucks.

Keep in mind there are some factors to pay attention to when installing a pan feeder on an incline to optimise the process. A properly designed hopper, the angle of inclination, the design of the support structure and the access and stair system around the feeder are all key factors.

Apron feeder optimal speed – faster is always better, right?

The common misconception around operating any equipment is: “faster is better.” In the case of apron feeders, nothing could be further from the truth. Optimal speed comes from finding that balance where efficiency meets transportation speed. They do operate at slower speeds than belt feeders, but for a good reason.

Normally, the optimal speed of an apron feeder is 0.05-0.40 m/s. If the ores are non-abrasive, the speed can increase to above 0.30 m/s due to the likely reduced wear.

Higher speeds would hurt an operation: if your speed is too high, you run the risk of accelerated wear of components. Energy efficiency, too, decreases due to the increase in energy demand.

Another concern to keep in mind when running an apron feeder at high speeds is the increased possibility of fines being generated. There can be a grinding effect between the material and the pans. Not only would the generation of fines create more issues because of possible fugitive dust in the air, but this also creates a more hazardous work environment for employees overall. So, finding an optimal speed is more important for the productivity and operational safety of the plant.

What are the limitations on size and type of ore?

Apron feeders do have limitations when it comes to the size and type of ore. The limitations will vary, but there should never be senseless dumping of material onto the feeder. You will need to not only factor in the application you will be using the feeder for, but also where in the process this feeder will be placed.

Generally, an industry rule to follow for your apron feeder dimensions is that the width of the pans (inside skirts) should be twice the maximum lump size of the material. Other factors, like a properly designed open hopper incorporating the use of “rock turning plates”, can affect the pan size, but that’s only relevant in certain circumstances.

It is not unusual for 1,500 mm of material to be extracted if a 3,000 mm wide feeder is used. Material of minus-300 mm from crusher ore stockpiles or storage/blending bins is typically extracted with apron feeders to feed secondary crushers.

What information is required when sizing an apron feeder?

When sizing an apron feeder and respective drive system (motor), as with a lot of equipment in the mining industry, experience and knowledge of the entire process is valuable. Apron feeder sizing requires basic knowledge of plant data to be able to accurately fill in the criteria needed for a vendor’s “application data sheet” (or however the vendor receives their information).

Basic criteria that should go into this includes feed rate (peak and normal), material characteristics (such as moisture, gradation and shape), maximum lump size of the ore/rock, bulk density of the ore/rock (maximum and minimum) and feed and discharge conditions.

However, occasionally there can be added variables to the apron feeder sizing process that should be included. A primary additional variable that vendors should be asking about is the hopper configuration. Specifically, the hopper shear length opening (L2) directly above the apron feeder. When applicable, this is not only a key parameter in properly sizing the apron feeder, but also the drive system as well.

How does “bulk” density affect the sizing of an apron feeder?

As stated above, bulk density of the ore/rock is one of the basic criteria requirements that should be included for effective apron feeder sizing. Density is the weight of material in a given volume and usually bulk density is measured as tonnes/cubic meter (t/m³), or pounds/cubic foot (lbs/ft³). One specific note to remember is that bulk density is used for apron feeders and not solid density like in other mineral processing equipment.

So why is bulk density so important? Apron feeders are volumetric-type feeders, which means bulk density is used to determine the speed and power needed to extract a certain tonnage per hour of the material. The minimum bulk density is used to determine the speed, and the maximum bulk density establishes the power (torque) needed for the feeder.

To conclude, it is important the correct “bulk” density and not “solid” density is used for sizing apron feeders. If these calculations are incorrect, this could jeopardise the resulting feed rate for the downstream process.

How do you determine the hopper shear length of the apron feeder?

Identifying the hopper shear length is a key component for correctly sizing and selecting an apron feeder and drive system (motor). But, how can this be determined? The hopper shear length is the dimension from the back plate of the hopper at the skirt line to the shear bar located at the exit end of the hopper. It sounds very simple, but it is key to note that this should not be confused with the dimension at the top of the hopper where material is loaded.

The goal of finding this measurement of the hopper shear length is to establish the actual shear plane line of material and where material inside the skirts is separated (sheared) from the material inside the hopper (L2). The resistance to shear the material is typically estimated to be between 50-70% of the total force/power. This calculation of the shear length will result in either insufficient power (lost production) or excessive power (rising operating expenses (opex)).

How do I find the optimal length of my apron feeder?

Spacing of equipment is essential to any plant. As mentioned before, apron feeders can be installed on an incline to save space. Selecting the correct length of an apron feeder will not only reduce capital expenditure (capex), it will also reduce power consumption and opex.

But how is the optimal length determined? The optimum length of an apron feeder is one that can fulfil the required duty in the shortest length possible. However, in some cases for an operation, the choice of feeder might want to be a little longer to “convey” materials to reach downstream equipment and eliminate a transfer point (and unnecessary costs).

To determine the shortest and optimal feeder possible requires flexibility in the layout of positioning the apron feeder under the hopper (L2). After determining the shear length and bed depth, the overall length can then be minimised just enough to prevent what is referred to as “self-flushing” over the discharge end when the feeder is idle.

I properly selected my apron feeder, but what about my drive system?

Selecting the proper drive system for your apron feeder will depend on the operation and goals of the feeder. Apron feeders are designed to be ran at variable speeds to extract from storage and feed downstream at a controlled rate of speed for maximum efficiency. The material could vary depending on factors such as the season of the year, orebody, or blasting and blending patterns.

The two types of drives suited for variable speeds are a mechanical drive using a gear reducer, inverter duty motor and variable frequency drive (VFD), or hydraulic motor and power unit with a variable pump. Today, variable speed mechanical drives have been proven as the preferred drive system due to the advancements in technology and capex benefits.

Hydraulic drive systems do have their place but are not seen as the ideal option between the two variable drives.

This Q&A was taken from a series of Metso blogs on apron feeders. For more information, please follow these links:

https://www.metso.com/blog-hub/mining-minds/feeding-the-facts-part-1-apron-feeder-basics/

https://www.metso.com/blog-hub/mining-minds/feeding-the-facts-23-proper-sizing-and-selection-of-your-apron-feeder/

Future-proofing mineral processing plants

Automation, Comminution of minerals, IoT, Mineral processing, Mining events, Mining services, Mining software, Water management, , , , , , , , , , ,

As minerals processing, digital plants and effective plant operations become more important for mining companies, Australia’s largest mining event is set to examine the challenges of processing plants of the future.

Finding intelligent solutions, future-proofing grinding circuits and embracing the opportunities of digitisation will be discussed at the International Mining and Resources Conference (IMARC) in Melbourne next month (October 29-31).

Ahead of the conference, Sandvik Lifecycle Development Manager, Simon Adams; CRC ORE Chief Executive and Managing Director, Ben Adair; and Weir Minerals Global HPGR Product Specialist, Bjorn Dierx, discussed the issues in a special IMARC webinar.

All agreed mining companies faced increased challenges as ore stocks depleted, forcing them to move to more remote locations and dig deeper in a bid to maintain recovery rates of past years.

Dierx, who will deliver an IMARC presentation on dry air classification technology to remove the need for water, said: “Our customers are under immense pressure to reduce energy consumption, use less water and reduce carbon emissions.

“Overall, as commodities are depleting, companies are making large investments in new plants to dig deeper, crush more ore and at remote locations with limited access to power and water to achieve the same recovery rates as the past 20 years.”

He said about 3% of global energy consumption was attributed to crushing rock so greater efficiencies in comminution would make a big contribution to reduced emissions.

For Adair, efficiencies are available now in existing operations.

“It’s important to optimise and run your equipment to the best of its ability,” he said. “Most sites I visit that’s simply not the case. We are a little bit delusional if we think we are there at the moment in a digital sense in optimising various grinding circuits.”

He agreed limited access to water was a critical element.

“It’s interesting water was mentioned. That is one of the major challenges for the industry. It simply won’t have access to potable water and it will have to head rapidly to a closed-loop situation otherwise the costs will be extraordinarily prohibitive,” he said.

“Most of our work is done in the sorting space. . . It’s patently ridiculous and it has been for the past 15 to 20 years that we mine something and stick it through various expensive process plants when in fact 99% of it has no value whatsoever.

“If you are looking at the mine of the future, it is going to be about exploiting heterogeneity at the mine face as opposed to deliberately destroying heterogeneity and looking for homogenous feeds for downstream processing plants.”

The digital transformation at the plant and processing level offered opportunities for miners, with Adams saying the ability to collect and analyse data was crucial.

“If you can have digitisation and automation that moves towards cognitive behaviour, once you get those algorithms down you can have far more efficient plants operating through that process,” he said.

“We have to turn data into knowledge; looking at power consumption and efficiencies and getting to the cognitive stage where we can foresee failures or predicted failures and we can capture them early and shut down in an organised fashion.”

Dierx said digital transformation presented a big opportunity for the industry to attract new people from traditional software programmers and those in the gaming industry to work in the mining industry.

“The big iron ore miners, if those autonomous devices need to be switched off, they use Xbox controllers to correct them. That’s good news for children of today,” he said.

“From an education perspective, there is still some work to be done. Universities need restructuring to ensure we not only educate traditional operators, metallurgists and process engineers but ensure that understanding algorithms and working with digital tools become standard practice.”

IMARC, developed in collaboration with its founding partners the Victorian State Government of Australia, Austmine, AusIMM and Mines and Money, is where global mining leaders connect with technology, finance and the future. For more information, please visit https://imarcmelbourne.com/

International Mining is a media sponsor of the IMARC event

Weir Minerals confronts froth pumping problems

Equipment maintenance, Mineral processing, Mining equipment, Mining maintenance, Mining services, Water management, , , , , , ,

As miners look to reclaim more minerals from the flotation process through froth pumping they are potentially exacerbating existing problems in their circuit design, according to Les Harvey, Regional Product Manager for Slurry Pumps at Weir Minerals.

Mining companies are making these moves to counteract declining ore grades, but, occasionally these techniques are deployed without making allowances for the design of the mine’s froth pumping equipment.

Froth pumping remains one of the most complex engineering challenges in minerals processing, as air management issues in the hopper, sump and pump itself lead to inefficient pumping, increased maintenance and even lost product, according to Weir.

“We’ve started to notice a pattern among our customers who are having trouble with their froth pumps,” says Harvey. “By using more flocculants and other chemicals designed to improve mineral recovery, they’re exacerbating existing problems in circuit design and reducing the returns they’re looking for.”

Close examination of the froth’s makeup and physical qualities is often needed to resolve issues. Ensuring operators’ froth handling equipment adheres to best design practices is an important first step in resolving problems, according to Weir.

Maintaining pressure in the pump

The key challenge in froth pumping is dealing with air in the pump itself, as it tends to naturally centrifuge into the impeller’s eye where it builds up into an ‘air lock’ which impedes the movement of slurry through the pump, Weir said.

In addition to reducing the pump’s efficiency, the air build up in the pump will reduce the flow through the pump and increase the slurry level in the suction hopper. The increased slurry level may push the pocket of air through the pump, causing surging and excessive vibration which can damage the pump bearings, impeller and shaft.

“The best way to manage air in a froth pump is to invest in a froth pump with a Continuous Air Removal System (CARS), which we have in our Warman AHF, MF and LF pumps,” Harvey says.

CARS allows air to move from the pump’s impeller eye to an air collection chamber in the back through a vent hole in the impeller. From that chamber, a flow inducer removes the air from the pump through a vent pipe.

Harvey said: “It’s also important to position the pump’s discharge pipe at the top of the pump, or at a 45° angle as this will give air trapped at the top of the casing a way to escape the pump.”

Solving problems in the sump and hopper

A persistent problem Weir sees is when hoppers designed to meet the demands of slurry pumping are used in a froth pumping application, Harvey said. “Slurry hoppers require turbulence to prevent the mineral content from settling, while turbulence in a froth pump prevents the air from escaping and leads to blockages.”

Tanks designed for froth pumping promote continuous circular movement, where solids and liquids are sent to the outside of the sump for further transport while air centrifuges into the centre where it can be removed. This ‘whirlpool’ movement can be encouraged by introducing the slurry from the top of the tank at a tangential angle, according to Weir.

Conical designs, rather than those with a flat or rounded floor, further improve the flow of minerals and froth into the pump, the company added.

Smooth sailing from the tank to the pump

To prevent blockages, the intake pipe which links the tank to the pump should be large diameter and slope downwards towards the pump, according to Weir. This design allows escaped air to separate and travel back up the pipe where it can escape from the sump, rather than build up into blockages.

Harvey said: “The shorter your intake pipe, the harder it is for blockages to build up. However, in addition to a maintenance spool and isolation valve, it’s a good idea to leave enough space for a water injection port, which is useful for flushing out any solids build up.

“To make maintenance easier, a dump valve can be included on the suction side of the pump, between the pump and the isolation valve. This will allow you to drain slurry from the pump and discharge pipe system when stopping the pump for maintenance.”

Understanding tenacious froths

Froths are often classified as either brittle – with large air bubbles that break easily – or tenacious – where air forms tight bubbles around minerals and is difficult to separate. Froth being more tenacious than was accounted for is a frequent cause of blockages as air cannot effectively be removed, Weir says.

Harvey said two things are happening in the market today: One, mine operators are grinding the product much finer than before to liberate more from the waste rock. Two, they’re using flocculants that produce much smaller bubbles which lock up the air a lot more than brittle froths.

“We’re working together with customers to find ways to manage these more tenacious froths, by looking at their circuit design and dealing with areas where the air could accumulate and block the system, paying particular attention to their pumps, pipes and sumps,” he said.