Tag Archives: in-pit crushing and conveying

Metso Outotec aims for higher capacities as ore sorting offering develops

Base metals, Bulk handling, Environmental, Mineral processing, Mining equipment, Mining services, Precious metals, Steel and iron ore, Sustainable mining, Water management, , , , , , , , , , , , , , , , , , , , , ,

The entry of Metso Outotec into the bulk ore sorting space arguably heralds the beginning of a new stage of market adoption – one that is focused on significant throughputs across multiple commodities.

In May, the mining OEM announced a collaboration agreement with Malvern Panalytical, a company that has been using Pulsed Fast Thermal Neutron Activation (PFTNA) technology onboard its cross-belt analysers to analyse and help divert ore and waste streams with improved accuracy.

Up until that announcement, Metso Outotec had mooted the benefits of bulk ore sorting in several industry articles. On the smaller scale, it had also renewed its ongoing agreement with particle ore sorting major player, TOMRA.

The company said its agreement with Malvern Panalytical, which has previously worked on bulk sorting projects with Anglo American among others, brought together its expertise in crushing and bulk material handling solutions with Malvern Panalytical’s ore analysis nous to offer an industry-leading portfolio of solutions for bulk ore sorting.

Rashmi Kasat, Vice President, Digital technologies at Metso Outotec, said in the press release that the pact with Malvern Panalytical would allow the company to meet the industry’s increasing sustainability and resource efficiency needs in an enhanced way in the early comminution stage.

“Sensor-based bulk ore sorting and data-driven analysis upgrades low grade or waste stockpiles, making them economical and far less energy-intensive to treat,” she said.

There are obvious positive benefits up- and down-stream of sensor-based sorting too, with the ability to carry out a low-cost mining method (upstream), as well as reduced capital investments in downstream equipment already shown with early-adopter projects.

That is before considering the relative energy and water reduction requirements that come with applying the technology.

Kasat later told IM that the company’s existing portfolio of material handling modules, crushing stations or mobile crushing equipment, as well as bulk material handling solutions, already “complement” the concept of bulk sorting.

“The addition of the bulk sensor is easily achieved,” she clarified. “The diversion mechanism will be included as well to be able to offer the whole plant out of one hand.”

With crushing stations – at least in the in-pit crushing and conveying (IPCC) space – that can go up to 15,000 t/h (see the company’s Foresight™ semi-mobile primary gyratory station), the prospect of Metso Outotec making a concerted effort to get into the bulk ore sorting space bodes well for the rising throughputs of projects.

NextOre recently claimed it had commissioned the world’s largest bulk ore sorting system at First Quantum Minerals’ Kansanshi copper mine in Zambia. This installation, which uses the company’s magnetic resonance technology, comes in at a 2,800 t/h-rated capacity.

Scantech, meanwhile, recently confirmed it has a GEOSCAN GOLD installation using prompt gamma neutron activation analysis technology for bulk sensing/sorting up and running that uses a diversion system at conveyed flow rates of more than 6,000 t/h.

Kasat, without naming a range, confirmed Metso Outotec was targeting “higher capacities” in line with the sensors available on the market. She also clarified that the agreement with Malvern Panalytical was “non-exclusive”.

“We will choose all our sensor/analyser partners strategically,” she explained. “Malvern Panalytical has a leading position and history in this field with proven technology for ore sensing. We will leverage our and their Tier 1 position in the industry for our bulk ore sorting offering.”

Malvern Panalytical uses Pulsed Fast Thermal Neutron Activation technology onboard its cross-belt analysers to analyse and help divert ore and waste streams with improved accuracy

As the type of sensor to be employed varies based on several factors including mineralogy, plant capacity, application of bulk ore sorting, etc, Metso Outotec will identify the right partners for the right need, she explained.

The major constraints for these sensors are often measurement times and sensor penetration, according to Kasat.

“There are very few sensors out there that can do sensing of a 500-mm-deep bed of rock on a conveyor belt, moving at 5-6 m/s,” she said. “But our current and future prospective partners are working on developing the technologies to reduce measurement times without compromising the accuracy of measurement.”

The mining OEM is looking to, in most cases, provide ‘plug and play’ flowsheets for bulk ore sorting and then carry out the required customisation per sensor.

This plan reinforces Kasat’s assertion that there is no ‘one-size-fits-all’ concept in bulk ore sorting applications.

For new projects, the process could see the company start with metallurgical testing, progress to mobile/fixed pilot plants in the “backyard” to test the accuracy of the sensors for the given application, and then find the right solution for the customer’s use case.

Renato Verdejo, Business Development Lead for Bulk Ore Sorting at Metso Outotec, added: “For existing plants, we will install the sensor over the belt conveyor and analyse the results after selecting the right sensor for this sorting application.”

Metso Outotec intends to focus on major commodities like copper, iron, nickel and gold, among others, with applications such as waste/ore sorting, low grade re-crushing and beneficiation process optimisation.

Within this wide remit – and in line with its non-exclusive agreements with Malvern Panalytical and TOMRA – the company is also considering the combination of both bulk and particle sorting in flowsheet designs.

Metso Outotec, in 2021, renewed its ongoing agreement with particle ore sorting major player, TOMRA

“The combination of the superior throughput of a bulk application with the selectivity of particle sorting in a rougher-scavenger setup is something that can bring sorting to high volume mines in the future,” Kasat said.

“Plant concepts and flowsheets have already been conceptualised and we expect the first deliveries to be in pilot stations to test the sensors on site,” she added, saying that the tonnage requirements for bulk ore sorting sensor validation meant a bulk sensor would have to be piloted in the field to get statistically meaningful data about the properties of the deposit.

Metso Outotec’s crushing system offering will form the “base” for these solutions, with ore sorting optionality available to all customers, she said.

This sensor-based optionality also overlaps with another in-demand part of Metso Outotec’s business: IPCC.

The company’s dedicated team in Germany are responsible for this area, developing projects backed by comprehensive studies.

They – like most of the industry – are aware of the potential application for sensor-based ore sorting in IPCC projects.

Markus Dammers, Senior Engineer of Mine Planning for Metso Outotec and one of the team members in Germany, said there were applications for both bulk and particle sorting in IPCC applications, with the former likely integrated after primary crushing and the latter after secondary/tertiary crushing.

“Bulk ore sorting in an IPCC application should be integrated after primary crushing in order to recover marginal material determined as waste in the block model, or reject waste from the ore stream,” he said.

Bulk ore sorting in an IPCC application should be integrated after primary crushing in order to recover marginal material determined as waste in the block model, or reject waste from the ore stream, according to Markus Dammers

If integrated after secondary or tertiary crushing, it becomes less effective, with the ore’s heterogeneity decreasing every time the ore is rehandled, transferred, crushed, blended, etc.

“In this manner one can take advantage of the natural variability in the deposit, rather than blending it out, with bulk ore sorting,” he said.

After secondary and tertiary crushing, particle sorting may be applied as a “standalone or subsequent ‘cleaner’ process step”, he added.

With Metso Outotec open to the inclusion of ore sorting in fully-mobile, semi-mobile and stationary crushing stations within an IPCC context, the company has many potential customers – existing and new – out there.

And that is just in IPCC applications.

The company also has hundreds of crushing stations on fixed plant installations that could represent potential sorting opportunities.

Metso Outotec, on top of this massive install base, has a few advantages over traditional ore sorting vendors in that it understands the plant that goes around the analysis and diversion process associated with ore sorting; knows how important uptime is to its customers; and, through sophisticated modelling, realises what impact changes in the flowsheet will have up- and down-stream of such equipment.

“The key point here is to have all the equipment to handle and process the ore to feed the sorter and, later, having the technology to divert the material and retain the availability of the plant without changes,” Kasat said.

Energised by its Planet Positive aims of responding to the sustainability requirements of its customers in the fields of energy or water efficiency, emissions, circularity and safety, the company is now ready to flex its processing plant muscles to increase the industry’s adoption of bulk and particle sorting technology.

Metso Outotec and FAM to collaborate on IPCC, tailings projects

Bulk handling, Mining equipment, Mining services, Mining techniques, Power supply for mines, Sustainable mining, Water management, , , , , ,

Metso Outotec and FAM GmbH have signed a global non-exclusive co-operation agreement on the delivery of integrated end-to-end solutions for in-pit crush and convey (IPCC) and tailings management plants to the mining industry.

The combination of the companies’ leading expertise in their respective fields will allow the parties to form the market’s strongest offering for IPCC and tailings management plants, they said.

“Mine electrification, reduction in power and water consumption, as well as de-risking tailings disposal, are common goals for the mining industry and Metso Outotec to improve sustainability,” Metso Outotec said. “State-of-the-art IPCC and tailings management plants cater for these requirements.”

Markku Teräsvasara, President of the Minerals business area at Metso Outotec, said sustainability is a top priority for Metso Outotec.

“In addition to our investments to develop our IPCC and tailings management plant offering, we are pleased to be able to announce our cooperation with FAM,” he said. “This will allow us to meet our customers’ growing demand in such plants, where spreaders or conveyor bridges are required.”

Torsten Gerlach, CEO of FAM, added: “FAM’s leading technology in dry tail stacking systems and spreaders ties well in with Metso Outotec’s hard-rock crushing and minerals processing portfolio. Where end-to-end systems are required, we are glad teaming up with a strong partner.”

Piedmont looks at IPCC, Metso Outotec alkaline pressure leach for lithium project

Energy minerals, Environmental, Mineral processing, Mineral project development, , , , , , , , , , , , ,

Piedmont Lithium’s plan to build out an integrated lithium hydroxide business from a base in North Carolina, USA, has advanced with the release of a scoping study that, it says, confirms that Carolina Lithium will be one of the world’s largest and lowest-cost producers of lithium hydroxide with a “superior” sustainability footprint.

Piedmont Carolina Lithium contemplates a single, integrated site, comprising quarrying, spodumene concentration, by-products processing, and spodumene conversion to lithium hydroxide at its site in Gaston County. There are currently no such integrated sites operating anywhere in the world, with the company saying the economic and environmental advantages of this strategy are compelling.

The latest study outlined a production target of around 4.96 Mt of 6% Li2O spodumene concentrate (SC6), averaging approximately 248,000 t/y of SC6 over the 20-year mine life. This equates to an average of 1.95 Mt/y of ore processed, totalling some 37.4 Mt of run-of-mine ore at an average grade of 1.09% Li2O (undiluted) over the 20-year mine life.

Of the total production target of 4.96 Mt of SC6, some 1.19 Mt will be sold to third parties during the operational life and approximately 3.77 Mt will be supplied to Piedmont’s chemical plant operations for conversion into lithium hydroxide. This results in a total production target of about 582,000 t of lithium hydroxide, averaging approximately 29,095 t/y of lithium hydroxide over 20 years, the company said. The study also assumes production targets of 4.83 Mt of quartz concentrate, 7.51 Mt of feldspar concentrate, and 1.34 Mt of mica concentrate over the life of operations.

Piedmont envisages a total initial capital cost of $838.6 million for the project and an after-tax net present value (8% discount) of $1.92 billion.

While still very much preliminary, the flowsheet and mining process for this planned operation is of interest to any lithium developer looking for a ‘sustainable’ mining footprint.

The company currently envisages using a Metso Outotec alkaline pressure leach process as part of its plan. This will reduce emissions, eliminate sulphuric acid roasting and reduce solid waste, it said.

At the same time, in-pit crushing and conveyor systems are on the agenda, eliminating mining trucks in the study to reduce fossil fuel consumption.

Piedmont has also been working with a solar developer to build and operate a solar farm on Piedmont property capable of producing electricity to supply up to 100% of Piedmont needs.

The company will also co-locate all operations on the same proposed site in Gaston County to minimise any transit and allow unused by-product streams to be repurposed for site redevelopment, it said. This adds up, Piedmont says, to highly efficient land and water use compared with South American lithium brine production.

Keith D Phillips, President and Chief Executive Officer of Piedmont, said: “We are exceedingly pleased with the results of our updated scoping study. The economics of our project continue to impress, but I am particularly proud of the project’s sustainability profile.

“As we move forward to complete a definitive feasibility study for Carolina Lithium later in 2021, Piedmont has engaged Evercore and JPMorgan as financial advisors to evaluate potential strategic partnering and financing options for its North Carolina project. Given the project’s unique position as the only American spodumene project, with world-class scale, economics, and sustainability, we expect strategic interest to be robust.

CRC ORE simplifies complexity for value

Bulk handling, Comminution of minerals, IoT, Mineral processing, Mining events, Mining services, Precious metals, , , , , , , , , , , , , , , , ,

“There are a lot more variables to bulk ore sorting than just the technology,” Jon Rutter says.

The Principal Geologist of the Cooperative Research Centre for Optimising Resource Extraction (CRC ORE), Rutter knows his stuff. He has worked underground in both narrow-vein and mass-mining operations, as well as at large scale open-pit mines; in the base and precious metal arena.

During a presentation at International Mining Events’ IPCC Virtual event in early-February, he shared a slice of this knowledge while reviewing a recent installation project CRC ORE had been involved in at a platinum group element (PGE) operation.

“The intrinsic value of bulk ore sorting comes from the delivered heterogeneity,” Rutter said. “We have got to be able to sense and divert a higher-value pod of material versus an adjacent pod of lower-grade material on a conveyor.

“You essentially want to put more material into the mill that adds value – and not what destroys value.”

Looking at the wider bulk sorting opportunity in mining, Rutter explained the sensor diversion units (SDU) in bulk ore sorting were smaller than what the mine itself can typically offer in the form of a selective mining unit (SMU), which may be comprised of a dig block totalling around 15,000 t.

A truck offers a 100-300 t opportunity, while a shovel typically comes with a 50-100 t opportunity.

Even with a modest conveyor running at a 2,000 t/h rate, an on-board sensor (eg PGNAA or PFTNA) running at a 30 second integration time (the time to analyse one grade) would provide an SDU of 16.7 t. A sensor with lower integration time (eg XRF at 10 seconds) comes in at 5.6 t.

The ability to provide analysis down to this level has enticed several major companies into testing bulk ore sorting solutions.

Anglo American has trialled bulk ore sorting solutions at copper and platinum group metal mines, while BHP recently engaged CRC ORE to examine deployment of cutting-edge preconcentration techniques under its Grade Engineering® platform at the Olympic Dam mine, in South Australia.

The SDU with bulk sorting may be that much smaller than the SMU of a typical mine plan, but lab-level precision is not required for these solutions to work, according to Rutter.

“What I need is the ability to measure the metal content adequately,” he said. “When I say adequate, this incorporates the entire error bar of the system. That system includes the inherent geology, the mineralisation style and heterogeneity. We also need to consider the precision, accuracy and integration time – which is the technology constraint; but we also need to include the weightometers, the flop gates, the diversion gates, as well as that entire mining and materials handling process right from the start – from blasting, loading, hauling and dumping to the plant.

“But for bulk ore sorting what I end up requiring from this combined data is usually a binary decision: am I above or below a certain threshold?”

He expands on the bulk ore sorting (BOS) assessment process: “The other way of looking at this is simply considering it as planned ore loss and dilution. If we go back into that dig block, in that 15,000 t of material, I’ve already incorporated planned ore loss and dilution decisions or parameters into that SMU decision. So, if we look at bulk ore sorting, I am just talking about those different attributes – the error bars of a BOS system – as the inputs or parameters for BOS planned ore loss and dilution – it’s now just at a smaller and more precise opportunity.”

The company took a two-phase approach to the BOS opportunity at the PGE operation in question.

The first phase involved carrying out heterogeneity analysis of the orebody; correlation analysis of PGEs to base metals; selection of sensor technologies (XRF and PGNAA were selected in this case), design, layout and equipment selection for the bulk ore sorting plant; natural deportment analysis of the orebody; development of a preliminary business case; the ore type selection and sampling strategy; and project planning and management.

CRC ORE and the company in question settled on a solution where a Caterpillar 992 wheel loader dropped material off to a system using a combination of grizzly, feeder, sizer, conveyors, diverter, stackers and associated equipment from MMD, used in conjunction with an ore sensing system equipped with both PGNAA and XRF sensors to continuously measure the elemental composition. The PGNAA sensor provided a “penetrative” analysis calculation whereas XRF provided a “surface” sensing calculation, Rutter explained.

An incline conveyor ahead of the diverter gate and the accept/reject stream provided the 30 second integration time the PGNAA analyser required.

Phase two of the project involved online and offline (pre-install) work; sensor calibration; proving the technology; and proving the technology can drive physical separation.

Rutter said the completion of static calibration of the sensors saw the PGNAA sensor 20-30% calibrated, and the XRF sensor 70-80% calibrated.

This outcome harked back to Rutter’s assertion that “bulk ore sorting implementation is not a plug and play opportunity”.

A dynamic calibration in online mode completed under normal conditions was required to get the PGNAA sensor up to speed. This process, meanwhile, solidified the operation of the XRF sensor.

While the two sensors were calibrated in different ways, Rutter showed data that confirmed both were in unison when it came to reading the ore/waste that came through the conveyor (see right-hand graph below).

“The two sensors are independent of each other and fundamentally very different, but they can work well together, or separately,” he said.

CRC ORE was able to prove the technology by running the same sample through the circuit a number of times, as Rutter explained: “We fed 15-20 t of run of mine material into the hopper and repeated the process 15 times, putting the same 15-20 t sample through the system. We could then start to determine the precision and accuracy of the sensors and the system.”

For further verification, the sample was crushed, sub sampled and assayed.

“We wanted a binary response to ore and waste to build confidence,” Rutter added.

Phase three involved the ramp up to production scale, going from, say, 500 t/h to 1,000 t/h; carrying out validation by campaign; and finally integrating with the operation.

There were several lessons all mining companies – and bulk sorting vendors – should keep in mind from such a project, Rutter said.

Operations need to assess the impact of mixing across the entire materials and mining handling process as soon as possible, for one.

“The earlier we can put this data into the system, the better,” Rutter said. “Without a heterogeneity signature, we cannot implement bulk ore sorting.”

He also stressed the importance of timely feedback. Sensor calibration, a secondary crushing/sampling plant and assaying were all required to build confidence in the solution.

Rutter added: “The proper calibration of sensors does require a considerable and ongoing effort…but that is no different from any other process plant or equipment.”

Operators also need to be wary of where they set these solutions up in mines, recognising this heterogeneity dynamic.

“Bulk ore sorting is quite unlikely to be universally suited to the entire deposit,” Rutter said. “The analogue for this is a flotation plant; there are ore types in the mine where you achieve better performance in the flotation plant and others where you get worse performance.”

BHP weighs trolley assist and IPCC as part of decarbonisation efforts

Base metals, Bulk handling, Environmental, Mining equipment, Mining industry recognition, Power supply for mines, Steel and iron ore, Sustainable mining, , , , , , , , , , , , , , , , , , , , ,

BHP has provided an update on its progress on climate action, new climate commitments and how it integrates climate change into corporate strategy and portfolio decisions in a new report.

The company’s climate change approach focuses on reducing operational greenhouse gas emissions, investing in low emissions technologies, promoting product stewardship, managing climate-related risk and opportunity, and partnering with others to enhance the global policy and market response, it says.

“BHP supports the aim of the Paris Agreement to limit global warming to well below 2°C above pre-industrial levels, and pursue efforts to limit warming to 1.5°C,” the company clarified.

It explained: “BHP has been active in addressing climate risks for more than two decades, and has already established its long-term goal of achieving net zero operational (Scope 1 and 2) emissions by 2050 and its short-term target of maintaining operational emissions at or below financial year (FY) 2017 levels by FY2022, using carbon offsets as required.”

In the past year, BHP has made progress on this aim, announcing that the Escondida and Spence copper mines in Chile will move to 100% renewable energy by the mid-2020s, and, last week, awarding new renewable energy contracts for its Queensland coal assets, and the world’s first LNG-fuelled Newcastlemax bulk carrier tender.

BHP’s climate change briefing and 2020 climate change report outline how the company will accelerate its own actions and help others to do the same, it said. Today’s update sets out:

  • A medium-term target to reduce operational greenhouse gas emissions by at least 30% from adjusted FY2020 levels by FY2030;
  • Scope 3 actions to contribute to decarbonisation in its value chain. This includes supporting the steelmaking industry to develop technologies and pathways capable of 30% emissions intensity reduction with widespread adoption expected post-2030 and, in terms of transportation, supporting emissions intensity reduction of 40% in BHP-chartered shipping of products;
  • Strengthened linking of executive remuneration to delivery of BHP’s climate plan; and
  • Insight into the performance of BHP’s portfolio in a transition to a 1.5°C scenario.

The report also outlined some examples of emission reduction projects the miner is considering, which will be weighed as part of the maintenance capital category of its capital allocation framework. This includes solar power installations; alternative material movement technologies such as overland conveyors and in-pit crush and convey solutions; and trolley assist to displace diesel for haul trucks.

The company expanded on this in its report: “The path to electrification of mining equipment will likely include solutions such as trolley assist, in-pit crush and convey, overland conveyors and battery solutions.

“Diesel displacement represents a higher risk, higher capital step towards decarbonisation, so a phased approach to execution is proposed with particular emphasis on Minerals Americas-operated assets that are further advanced on the decarbonisation journey. Taking a transitional approach to electrification provides flexibility to allow for the potential for rapid development of emerging technologies and to resolve the complexities of integrating these technologies into existing operations.

“During FY2021, we will seek to collaborate further with International Council on Mining and Metals members, industry and original equipment manufacturers to progress research and development to reduce costs and assess any potential impacts from electrified mining equipment solutions to replace current diesel options.”

BHP Chief Executive Officer, Mike Henry, said of the report: “I’m pleased today to show how we are accelerating our own actions and helping others to do the same in addressing climate change. We see ourselves as accountable to take action. We recognise that our investors, our people and the communities and nations who host our operations or buy our products have increasing expectations of us – and are responsive to these.

“Our approach to climate change is defined by a number of key requirements. Our actions must be of substance. They must be real, tangible actions to drive emissions down. We must focus on what we can control inside our business, and work with others to help them reduce emissions from the things that they control. To create long-term value and returns over generations, we must continue to generate value and returns within the strong portfolio we have today, while shaping our portfolio over time to benefit from the megatrends playing out in the world including decarbonisation and electrification.

“Our portfolio is well positioned to support the transition to a lower carbon world aligned with the Paris Agreement. Our commodities are essential for global economic growth and the world’s ability to transition to and thrive in a low carbon future. Climate change action makes good economic sense for BHP and enables us to create further value.”

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/

B2Gold weighs up in-pit crushing and conveying as Fekola mine expansion economics stack up

Bulk handling, Mine operation news, Mineral processing, Mineral project development, Mining equipment, Mining finance, Mining project news, Mining services, Power supply for mines, Precious metals, , , , , , , , , , ,

B2Gold’s plan to expand its Fekola gold mine, in Mali, by 1.5 Mt/y could see an up to $56 million investment in additional excavators, trucks, drills, support equipment and wheel loaders, according to the latest project economic study.

The expansion study preliminary economic analysis showed the company could increase throughput to 7.5 Mt/y, from the current 6 Mt/y base rate, by injecting just under $50 million over a period of some 18 months for processing expansion and upgrades.

As currently envisioned, the processing upgrade would focus on increased ball mill power, with upgrades to other components including a new cyclone classification system, pebble crushers, and additional leach capacity to support the higher throughput and increase operability.

“Critical path items include ball mill motors and the lime slaker, both of which will be commissioned in Q3 (September quarter) 2020,” B2Gold said.

“In parallel with the expansion, B2Gold is studying the addition of a solar power plant, which would reduce operating costs and greenhouse gas emissions. The current on-site power plant has sufficient capacity to support the expanded processing throughput, with or without the solar plant.”

On top of this, the company would need to invest in its mining fleet.

The current mining fleet consists of four Caterpillar 6020B excavators with haul trucks, drills, and support equipment to match, and mines an average of 36 Mt/y. The Whittle study results currently indicate mining production rates ranging from 54 Mt/y to 76 Mt/y are optimal to support the expanded processing rates over the life of mine and optimise head grade during the period 2020-2024.

B2Gold said: “Increased production will be achieved with the addition of two to four excavators with corresponding trucks, drills, and support equipment. Large front-end loaders would also be included to maintain fleet flexibility.

“Mine fleet expansion timing and scale will be optimised during Q2 (June quarter) 2019 and will generally be equipment loan/lease financed over a five-year period. The study has included $28 million for expansion to 54 Mt/y and an additional $28 million (for a total of $56 million) to go to 76 Mt/y.

“In parallel with the Whittle study, B2Gold is reviewing in-pit crushing and conveying as a means to reduce operating costs and potentially implement tailings and waste co-disposal at the Fekola mine.”

The expansion study estimated optimised that the life of mine could extend into 2030, including significant estimated increases in average annual gold production to over 550,000 oz/y during the five-year period 2020-2024 and over 400,000 oz/y over the life of mine (2019-2030).

This would see an increase in project net present value of approximately $500 million versus the comparable amounts in the company’s latest AIF mineral reserve life of mine model based on a $1,300/oz gold price and a discount rate of 5%.

NRW Holdings signs A$10 million deal to buy RCR’s Mining and Heat Treatment businesses

Bulk handling, Equipment maintenance, Mineral processing, Mining equipment, Mining mergers and acquisitions, Mining services, Mining techniques, , , , , , , , , , , , ,

NRW Holdings has entered into an agreement to acquire RCR Tomlinson’s Mining and Heat Treatment businesses for A$10 million ($7.3 million) in cash.

The agreement was signed with RCR’s administrators, which have been offloading various RCR subsidiaries since shortly after the company declared total liabilities of A$581.3 million alongside cash and equivalents of A$89.9 million in its 2018 financial year.

The purchase consideration will be funded from NRW’s existing cash reserves, with the deal expected to complete within the next two weeks, NRW said.

RCR Mining and Heat Treatment form part of the original RCR Tomlinson business established over 100 years ago.

RCR Mining includes the Mining Technologies business, which owns significant intellectual property across a range of products and processes and is recognised as a market leader by global resources clients, according to NRW.

“The Mining Technologies business is a leading national and international original equipment manufacturer and innovative materials handling designer with an extensive product range including apron and belt feeders, high capacity conveyors, slide gates, stackers, spreaders, fully track-mounted in-pit mining units (an example pictured above), sizers, scrubbers and screening plants,” NRW said.

One of RCR’s recent mining technology innovations is a 5 km relocatable conveyor, which includes a semi-mobile primary crushing station and feeds directly into Fortescue Metals’ Cloudbreak iron ore processing facility in the Pilbara of Western Australia.

Both the Mining Technologies and Heat treatment businesses have a high proportion of activity in equipment product support and maintenance (both on site and off site), NRW said, adding that the Heat Treatment business has facilities that include the largest stress relieving furnace in Australia.

Mining Technologies and Heat Treatment generated around A$110 million of revenue in the 2018 financial year and have a track record of delivering positive earnings, NRW noted, explaining the acquisition would be earnings per share accretive on a full-year basis, excluding integration and other one-off costs.

Jules Pemberton, NRW’s Managing Director and Chief Executive Officer, said the acquisition would allow NRW to provide incremental services, in line with its strategic objectives, to several core clients common to both NRW and the RCR businesses.

“In addition, the annuity style income from the maintenance activities of Mining Technologies and Heat Treatment will provide a platform to continue to build a broader service offering across an expanded resources and oil and gas client base.”