Tag Archives: ball mills

Metso Outotec addresses standardisation and flexibility needs with new grinding mills

Metso Outotec has, after reviewing the combined horizontal mill product offering from the Metso and Outotec companies, unveiled a “harmonised” Metso Outotec horizontal mill product line that, it says, represent the best of both legacy companies.

The Metso Outotec Premier™ horizontal grinding mills and Select™ horizontal grinding mills are designed for different customer segments and markets, and they have distinctly different features and benefits. In both lines, there are various mill solutions available for a wide range of applications.

The Premier horizontal grinding mills are customisable solutions built on state-of-the-art grinding mill technology, process expertise, and design capability, the company says. The Premier horizontal grinding mills are engineered to “excel and create vast possibilities” for customers and applications.

The Select horizontal grinding mills are a range of pre-engineered solutions that allow simple mill selection, simplified proposal preparation, and a streamlined order execution process. Select horizontal grinding mills feature a suite of technologies and conservative design parameters that meet or exceed operational goals, Metso Outotec claims. Select horizontal grinding mill sizes are available for applications up to 7.8 MW for both the SAG and ball mills. Rod mills are available up to Ø4.60 m x 6.10 m EGL.

“With the introduction of the Premier and Select horizontal grinding mills, Metso Outotec continues its over 100-year legacy in grinding,” Christoph Hoetzel, Head of Grinding business line at Metso Outotec, says. “Both lines have their own differences and benefits – but share the concepts and expertise that have made us an industry leader time and time again.”

He added: “As a combined company we have consistently led the way in grinding mill innovation. We’ve continuously pushed mill technology in the next size increment. Currently, we have the largest operating mills in the world, and we want to lean on that legacy in taking the next steps in mill size. In addition, it is important for us to continue to be a frontrunner in the development of a more robust suite of horizontal mill technologies, providing desirable options for customers looking for quick execution with reliable technology.”

The company says the Premier and Select mills come ready to be integrated with its mill reline equipment and full mining portfolio. The former includes the recently launched Mill Reline Machine (MRM), which has a capacity of 4,000 kg, as well as a broad selection of liner options, including the Megaliner™.

Latest Kamoa-Kakula copper studies reaffirm project’s world-class status

The latest economic studies on Ivanhoe Mines and Zijin Mining Group’s majority-owned Kamoa-Kakula project in the Democratic Republic of Congo have indicated the asset could become the world’s second largest copper mining complex.

First production at Kamoa-Kakula is less than a year away, but the project partners have continued with a series of economic studies that emphasise the world-class nature of the orebodies within their control.

The headline maker is the results of a preliminary economic assessment that has evaluated an integrated, multi-staged development to achieve a 19 Mt/y production rate at the mine, with peak annual copper production of more than 800,000 t.

At the same time, a prefeasibility study (PFS) has been carried out to look at mining 1.6 Mt/y from the Kansoko mine, in addition to 6 Mt/y already planned to be mined from Kakula, to fill a 7.6 Mt/y processing plant at Kakula.

A definitive feasibility study (DFS) has also evaluated the stage-one, 6 Mt/y plan at Kakula, which is currently being constructed and is less than a year away from producing first copper, according to Ivanhoe Co-Chair, Robert Friedland.

While the operation looks to have the scale of a world-class asset, it will also have top ranking ‘green’ credentials, according to Friedland.

“The Kakula mine has been designed to produce the world’s most environmentally-responsible copper, which is crucial for today’s new generation of environmentally- and socially-focused investors,” he said.

“Zijin shares our commitment to build the new mines at Kamoa-Kakula to industry-leading standards in terms of resource efficiency, water and energy usage, and minimising emissions. We are blessed with ultra-high copper grades in thick, shallow and flat-lying orebodies – allowing for large-scale, highly-productive, mechanised underground mining operations; and access to abundant clean, sustainable hydro electricity to power our mines – providing us with a distinct advantage in our goal to become the world’s ‘greenest’ copper miner and be among the world’s lowest greenhouse gas emitters per unit of copper produced.”

The project recently retained Hatch of Mississauga, Canada, to independently audit the greenhouse gas intensity metrics for the copper that will be produced at Kamoa-Kakula.

The Kamoa-Kakula Integrated Development Plan (IDP) 2020, as the companies refer to it, builds on the results of the previous studies announced in February 2019.

DFS to 6 Mt/y

The new DFS incorporates the advancement of development and construction activities to date, and has once again confirmed the outstanding economics of the first phase Kakula Mine, Ivanhoe said.

It evaluates the development of a stage one, 6 Mtpa underground mine and surface processing complex at the Kakula deposit with a capacity of 7.6 Mt/y, built in two modules of 3.8 Mt/y, with the first already under advanced construction (see photo). It comes with an internal rate of return of 77% and project payback period of 2.3 years.

The first module of 3.8 Mt/y commences production in the September quarter of 2021, and the second in the March quarter of 2023. The life-of-mine production scenario provides for 110 Mt to be mined at an average grade of 5.22% Cu, producing 8.5 Mt of high-grade copper concentrate.

The Kakula 2020 DFS mine access is via twin declines on the north side and a single decline on the south side of the deposit. One of the north declines will serve as the primary mine access, while the other decline is for the conveyor haulage system, which was recently commissioned.

The primary ore handling system will include a perimeter conveyor system connected to truck load-out points along the north side of the deposit. The perimeter conveyor system will terminate at the main conveyor decline.

The mining method for the Kakula deposit is primarily drift-and-fill using paste backfill (around 99%); with the exception of a room-and-pillar area close to the north declines, which will be mined in the early years of production. The paste backfill system will use a paste plant located on surface connected to a distribution system that includes a surface pipe network connected to bore holes located at each connection drive on the north side of the orebody, the company says.

The Kakula concentrator design incorporates a run-of-mine stockpile, followed by primary cone crushers operating in closed circuit with vibrating screens to produce 100% passing 50 mm material that is stockpiled.

At the end of August, the project’s pre-production surface ore stockpiles totalled an estimated 671,000 t grading 3.36% Cu, including 116,000 t of high-grade ore grading 6.08% Cu.

The crushed ore is fed to the high pressure grinding rolls operating in closed circuit with wet screening, at a product size of 80% (P80) passing 4.5 mm, which is gravity fed to the milling circuit.

The milling circuit incorporates two stages of ball milling in series in closed circuit with cyclone clusters for further size reduction and classification to a target grind size of 80% passing 53 micrometres (µm).

The milled slurry is pumped to the rougher and scavenger flotation circuit where the high-grade, or fast-floating rougher concentrate, and medium-grade, or slow-floating scavenger concentrate, are separated for further upgrading. The rougher concentrate is upgraded in the low entrainment high-grade cleaner stage to produce a high-grade concentrate.

The medium-grade or scavenger concentrate together with the tailings from the high-grade cleaner stage and the recycled scavenger recleaner tailings are combined and further upgraded in the scavenger cleaner circuit. The concentrate produced from the scavenger cleaner circuit, representing roughly 12% of the mill feed, is re-ground to a P80 of 10 µm prior to final cleaning in the low entrainment scavenger recleaner stage.

The scavenger recleaner concentrate is then combined with the high-grade cleaner concentrate to form final concentrate. The final concentrate is then thickened and pumped to the concentrate filter. Final filtered concentrate is then bagged for shipment to market.

The scavenger tailings and scavenger cleaner tailings are combined and thickened prior to being pumped to the backfill plant and/or to the tailings storage facility. Backfill will use approximately half of the tailings, with the remaining amount pumped to the tailings storage facility.

Based on extensive test work, the concentrator is expected to achieve an overall recovery of 85%, producing a very high-grade concentrate grading 57% copper. Kakula also benefits from having very low deleterious elements, including arsenic levels of 0.02%.

7.6 Mt/y PFS

The PFS evaluating mining 1.6 Mt/y from the Kansoko mine envisages an average annual production rate of 331,000 t of copper at a total cash cost of $1.23/lb copper for the first 10 years of operations, and annual copper production of up to 427,000 t by year four. This comes with an internal rate of return of 69% and project payback period of 2.5 years, according to Ivanhoe.

Development would see Kakula-Kansoko benefit from an ultra-high, average feed grade of 6.2% Cu over the first five years of operations, and 4.5% Cu on average over a 37-year mine life.

There are currently two mining crews at Kansoko, in addition to the 10 mining crews (three owner crews and seven contractor crews) currently at Kakula, with the ability to increase this number to fast-track the development of Kansoko, Ivanhoe said.

19 Mt/y option

The Kamoa-Kakula 2020 PEA presents initial production from Kakula at a rate of 6 Mt/y, followed by subsequent, separate underground mining operations at the nearby Kansoko, Kakula West and Kamoa North mines, along with the construction of a 1 Mt/y of concentrate direct-to-blister smelter. The smelter section of the study saw China Nerin Engineering act as the main engineering consultant with Outotec providing design and costing for propriety equipment.

The Kamoa North Area comprises five separate mines that will be developed as resources are mined out elsewhere to maintain the production rate at up to 19 Mt/y, with an overall life in excess of 40 years, Ivanhoe says.

For this integrated 19 Mt/y option, the PEA envisages $700 million in remaining initial capital costs, with future expansion at Kansoko, Kakula West and Kamoa North funded by cash flows from the Kakula mine, resulting in an internal rate of return of 56.2% and a payback period of 3.6 years.

This shows the potential for average annual production of 501,000 t of copper at a total cash cost of $1.07/lb copper during the first 10 years of operations and production of 805,000 t/y of copper by year eight, Ivanhoe said.

“At this future production rate, Kamoa-Kakula would rank as the world’s second largest copper mine,” the company said.

NRRI and Weir Minerals offer up HPGR alternative to Minnesota Iron Range operators

The University of Minnesota Duluth’s Natural Resources Research Institute (NRRI) is helping introduce high pressure grinding roll (HPGR) technology to Minnesota’s Iron Range.

Working with Weir Minerals, NRRI acquired an industrial-scale Enduron® HPGR to carry out testing on a variety of ores with this process. This is the only large scale HPGR dedicated to research in the US, NRRI claims.

The NRRI explained: “Traditional taconite pellet-making processes use a rod mill to get the rock to the consistency of coarse sand, and a ball mill to grind the rock into a fine powder. This technology is still in use on Minnesota’s Iron Range by some facilities.

“A taconite plant may have as many as 18 rod mills with one rod alone weighing as much as 500 Ib (227 kg). Tumbling around in the mills with the hard taconite wears away the rods and balls and need to be replaced frequently.”

This is a costly and energy-intensive process and the waste rods and balls are a disposal problem, according to NRRI.

NRRI researchers think there’s a better and more efficient way of carrying out this grinding process with the use of HPGRs.

Tim Lundquist, Weir HPGR Manager for North America, said: “NRRI has done a lot of testing for many of our projects. The proximity to the Iron Range is key, but we’ll also bring in material from all over the US, Canada, and elsewhere when it makes sense. Our preference is to work with NRRI whenever possible due to their flexibility, expediency and expertise.”

Unlike rod or ball mills, HPGRs reduce particles by compressing and crushing the feed between two counter rotating, parallel rollers with a small gap between them. This forces the rocks against each other. There are no rods or balls that need replacing and it reduces energy consumption by about 40% for certain ore types, Breneman said. It also substantially reduces water consumption compared with rod and ball mills.

Reducing energy, eliminating costly grinding media, and higher machine availability will make the Minnesota iron industry more cost competitive while also offering the opportunity to reduce greenhouse gas generation, NRRI said.

NRRI Metallurgical Engineer, Shashi Rao, Lead Researcher on HPGR-related projects at NRRI Coleraine, said: “It’s really helpful to the industry to have their ores tested in our large HPGR before replacing their rod or ball mills.

“We’re able to determine if the ore is amenable to high pressure roll crushing, identify the mineral composition, and test a variety of pressures and roll speeds. Third-party testing is very important.”

Keeping the project moving ahead during the COVID-19 pandemic required extra steps and protocols, according to NRRI. This work was coordinated by NRRI Project Engineer, Jeff Kinkel.

“The machine is isolated to one specific area,” Kinkel said. “We adhered to strict sanitation and masking requirements and communicated daily with the contractor doing the installation.”

NRRI acquired the HPGR technology via Weir Minerals from the shuttered Magnetation LLC operation and both organisations are sharing the cost of maintenance.

“This is a great example of a partnership project,” Kevin Kangas, NRRI Coleraine Director, said. “We’ve been working on this for over two years and it’s exciting to have the global interest in this capability.”

The process is now in place at a Minnesota Iron Range facility with a Weir Minerals Enduron HPGR.

On average, 53% of a mine site’s energy consumption is attributed to crushing and grinding ores, accounting for almost 10% of a site’s production costs, according to information from Weir Minerals. NRRI’s HPGR is manufactured in the Netherlands by Weir Minerals.

Metso completes mill lining hat-trick with Discharge End Megaliner

Metso has once again flexed its R&D muscles, launching a new and innovative product that, it says, can speed up and improve the safety of one of the trickiest and riskiest processes mill personnel carry out.

The Discharge End Megaliner builds on the Metso Megaliner™ concept the company introduced in 2012. Designed to reduce downtime by minimising the number of parts and people inside the mill during a relining process, the Megaliner has so far been installed in over 30 mills around the world.

A Megaliner element integrates multiple lifter and plate rows and has a minimum number of attachment points. Covering an area several times larger than conventional liners, these liners are light weight in relation to their size and, with threaded bushings, enable safer and faster relining processes to be conducted.

The initial 2012 Megaliner launch saw these lightweight liner parts developed for the mill shell. In 2015, Metso expanded the lining concept to the feed end of grinding mills. The company is now ready to tackle the tricky mill discharge end to complete the hat-trick.

Anssi Poutanen, Vice President of Metso’s Mill Lining product line, said the mill shell was the obvious starting point in the Megaliner evolution.

“The shell represents the largest number of components to install so the potential for time savings for customers was large, hence why the Megaliner started there,” he told IM. “We have since extended to the feed end of the mill and now to the discharge end.”

The new product, which has been in the development pipeline for some time, according to Poutanen, is by no means just a bolt on to the existing Megaliner range.

“Even though the discharge section of the mill lining process is not as big from a volume perspective, the need for long bolts and a complex fixing arrangement in conventional installations makes it one of the most time-consuming and risky processes to carry out,” he said. “The Discharge End Megaliner is a highly valued addition to our Megaliner range as many of our customers struggle with the process.”

The conventional process Poutanen references here is worth spelling out.

With grate discharge mills – typically SAG, AG and ball mills – the conventional relining process at the discharge end usually involves removing the dischargers and grates, replacing with new lined versions and hammering in large, long bolts through the layers to secure the liner components.

“Even if modern recoilless hammers are used, it is still a challenge,” Poutanen said. “When the bolts become loose, they are hazardous and can potentially injure personnel.” In this process, personnel are also inside the mill – one of the most dangerous sections of the whole process plant.

On top of the large, long bolts, nuts are also required to fix the panels in place with conventional lining processes, adding up to multiple individual pieces and attachment points that must be fixed securely from inside the mill, Poutanen explained.

The Discharge End Megaliner, meanwhile, sees dischargers, grates and segments preassembled into one large unit. These are equipped with threaded bushings that are secured with “short bolts” from – very importantly – outside of the mill, he said.

This makes for an up to 50% faster lining installation using up to 70% fewer parts than the conventional process, according to Metso.

Poutanen says the new Discharge End Megaliner can be applied to any type of grate discharge mill – there is no prerequisite for Megaliner liners in the shell and feed end, for example – as long as there is a wide enough trunnion opening to remove and replace the liners, and a liner handler of sufficient capacity.

Metso is targeting the large end of the grinding mill market with this new development. The larger the mill, the greater the throughput, which has a direct impact on the costs associated with potential downtime caused by the relining process, Poutanen explained.

This has already been tested out at Boliden’s Aitik mine, in Gällivare, Sweden, which is currently undergoing an expansion to 45 Mt/y throughput.

The base metal mine already has Megaliner mill liners on the shell and feed end of both of its primary AG mills and has tested the new Discharge End Megaliner over nine months at one of these 38 ft (11.6 m) mills.

The Aitik trial has proven around 70% fewer parts are required compared with the conventional process. Relining has also been carried out much quicker and safer, according to Poutanen.

Similar to LHD operators being removed from the cab in order to remotely operate loaders in potentially unstable areas of underground mines, the ability to carry out the relining process from outside of the mill ‘danger zone’ could be considered an initial stage towards a fully automated relining process.

Poutanen agreed: “I think at some point, we will see a higher degree of automation. It is unlikely to be binary; it will be a gradual process.”

He said the combination of the Megaliner and Metso’s camera-based liner positioning system – which is offered to all Megaliner customers as an “add on” to the liner handling equipment – could help make the process more autonomous.

In order to be able to develop this kind of fully autonomous package, a close collaboration with customers and liner handler suppliers is required, he said. “I think we are still a few years away from having the process move to fully autonomous mode.”

Metso to help Pavlik Gold double processing capacity

Metso says Pavlik Gold JSC has chosen it as the supplier for the key crushing and grinding equipment for its ore processing plant in Magadan, Russia.

The Pavlik gold plant, which commenced its operations in 2015, currently produces around 225,000 oz/y of gold. With the new equipment, the plant expects to double its ore processing capacity and increase gold production, according to Metso.

Metso’s delivery consists of the primary crushing station with a Nordberg® C160™ jaw crusher, one SAG mill and two ball mills with a total installed power of more than 20 MW. The circa-€25 million ($27 million) order has been booked in Metso’s March quarter orders received, with delivery expected to take place in the first half of 2021.

Alexey Muzychkin, SVP, Russia and CIS, Metso, said: “We greatly value our long-term cooperation with Pavlik Gold, where Metso’s equipment has been in use already for several years. We are sure that the experience and technical competence of both companies in this type of projects will help us rapidly achieve the goals.”

Earlier this month, FLSmidth announced that it would supply a new 7 Mt/y gold processing plant to the mine.