Tag Archives: chrome

Kazchrome achieves chrome tailings flotation breakthrough

Engineers at the Donskoy Ore Mining and Processing Plant of JSC TNC Kazchrome, in Kazakhstan, have successfully completed trials of a first-of-its-kind industrial flotation technology to increase the enrichment of chrome oxide-bearing tailings, Eurasian Resources Group reports.

Kazchrome, the world’s largest high-carbon ferrochrome producer by chrome content with a total resource base of over 200 Mt of chrome ore, is owned by ERG.

The novel technology is part of the group’s R&D efforts to maximise chromite concentrate output and reduce the site’s environmental footprint, the company reports, with the process yielding the recovery of over 55% of chrome oxide and conforming to the applicable requirements for concentrate used in ferrochrome smelting.

As a result of these trials, the flotation technology will be used to construct a new facility to process over 10 Mt of chrome oxide-bearing tailings with a planned annual capacity of 1.7 Mt for 450,000 t/y of chrome concentrate, ERG says.

Benedikt Sobotka, CEO of Eurasian Resources Group, said: “This pioneering technology is a major milestone on our path towards ensuring sustainable and low-cost chromite concentrate supply for our operations in Kazakhstan, and is part of the group’s broader strategy to reinforce our leading position in the global ferrochrome market.”

Sergey Opanasenko, Chairman of the Management Board of ERG R&D Centre, added: “We are very pleased with the results of the flotation trials, particularly considering the complex mineralogy and physical characteristics of our ores. Building on this success, we look forward to working on incorporating this technology into the design of our new tailings processing facility.”

Sedibelo Platinum to expand PPM operations and leverage Kell Technology

Sedibelo Platinum Mines has announced plans to expand its Pilanesberg Platinum Mines (PPM) operation on South Africa’s Bushveld Complex, as well as construct a 110,000 t/y beneficiation plant at PPM employing Kell Technology.

The company plans to mine the three contiguous deposits of Sedibelo Central, Magazynskraal and Kruidfontein – known as the Triple Crown properties – as part of the expansion. These three come with an estimated resource base in excess of 60 Moz of 4PGE.

The predominantly shallow deposits will enable safe and sustainable mining activities for potentially more than 60 years, according to the company. The approved expansion will be funded through Sedibelo’s existing cash resources and future cash flow, with first ounces from Triple Crown expected to be extracted in 2023.

The Triple Crown expansion will be mined simultaneously with ore from the existing open-pit UG2 and Merensky operation, using two separate decline shaft systems, the company said.

The existing PPM concentrator plant has the capacity to be used to process the Triple Crown ore as well as ore from the open pits. With minimal reconfiguration, the Triple Crown UG2 and Merensky ore will be blended and processed through the existing Merensky plant, thereby reducing capital expenditure as well as lowering operating cost significantly, it said.

Speaking of the 110,000 t beneficiation plant, Sedibelo said Kell Technology reduces energy consumption by some 82% with the associated significant reduction in carbon emissions, also improving recoveries and lowering operating costs.

“Benefitting from being robust in operation, Kell is unconstrained by concentrate grade, is insensitive to chrome levels as well as being resistant to other impurities,” it explained. “Hence, using Kell will improve the economic return of the Triple Crown expansion and is an integral part of Sedibelo’s future development.”

As applied to treatment of PGM concentrates, the Kell Process comprises four main unit operations (pressure oxidation, atmospheric leach, heat treatment and chlorination), all of which are conventional and in commercial use in the minerals and metals industry.

Sedibelo shares an interest in Kell South Africa with the Industrial Development Corp and Founder Keith Liddell, through Lifezone.

Arne H Frandsen, Chairman of Sedibelo, said: “Today is a significant day in Sedibelo’s history. We are opening our next door 60 Moz Triple Crown deposit, thereby securing the future of Sedibelo for many decades to come. The construction of our Kell plant will allow us to produce metal and lower our cost profile further. Equally important, it will reduce our carbon footprint and water usage significantly.

“We trust our environmentally friendly platinum group metals will become an important part of future electrification and the ‘green revolution’ used in fuel-cells around the world.”

Keith Liddell, Founder of Kell and CEO of Lifezone, said: “I developed Kell Technology as a cost-efficient alternative to the conventional smelting of PGMs. We are excited to now proceed with the construction of the Kell plant at PPM. The benefit for Sedibelo and the industry will be significant; delivering beneficiation, energy and cost advantages as well as a reduction in CO2 and SO2 emissions.”

TOMRA connects ore sorters to the cloud with TOMRA Insight

After a successful launch in its recycling division, TOMRA is rolling out its cloud-based data platform, TOMRA Insight, to mining customers.

TOMRA Insight enables sorting machine users to improve operational efficiencies through a subscription-based service that turns these machines into connected devices for the generation of valuable process data.

Following a successful launch last year by TOMRA Sorting Recycling, TOMRA is now also being made available to customers of TOMRA Mining and TOMRA Food. For all three industries, the platform is enhanced by new features and functionalities that make TOMRA Insight even more valuable than when it was launched to recyclers in March 2019.

The data from TOMRA Insight is gathered in near real time, stored securely in the cloud, and can be accessed from anywhere and across plants via a web portal available for desktop and mobile devices, according to the company.

Felix Flemming, Vice President and Head of Digital at TOMRA Sorting, said: “By capturing and using valuable data, TOMRA Insight is transforming sorting from an operational process into a strategic management tool. This tool is constantly becoming more powerful as we continuously develop it in response to customers’ needs and priorities. New functionalities and features are released every three weeks – a routine during which TOMRA works closely with customers in pursuit of shared objectives.”

Data captured by TOMRA Insight provides valuable performance metrics that help businesses optimise machine performance.

Operating costs are reduced by simplifying spare part ordering and offering flexible access to data and documentation, according to the company. Downtime is reduced by monitoring machine health and performance in near real time, identifying gaps in production and analysing potential root causes. This allows management to move to predictive and condition-based maintenance, preventing unscheduled machine shutdowns.

Throughput, meanwhile, is maximised by evaluating variations and optimising sorting equipment, accordingly. Sorting to target quality is enhanced by having accurate material composition data to enable decisions to be based on more detailed information.

For the mining and mineral processing industries, TOMRA Insight’s ability to collect detailed data from TOMRA’s sorting machines means that previously hidden information can lead to improvements in efficiencies and profitability.

Data captured by TOMRA Insight is analysed on behalf of customers by TOMRA Mining engineers, and key findings shared in confidential reports supplied to customers on a monthly basis. This arrangement has the advantage of combining objective statistical analysis with the interpretive skills of a service team familiar with the customer’s unique challenges, TOMRA says.

“TOMRA Insight’s data-gathering helps mineral processors in near real time and in retrospect,” the company said. “Machine operators are empowered to take prompt action in response to changes in material composition on the line and managers are empowered to make operational and business decisions based on more complete information.”

Comparisons between multiple sites or lines can now be made more accurately and difficult-to-reach processing operations can be remotely monitored from more convenient locations, the company said. This functionality is especially useful in the face of widespread travel restrictions related to COVID-19.

One early, pre-launch user of TOMRA Insight is the Black chrome mine in South Africa (pictured above), one of two mining projects that form the basis of the Sail Group’s plans for long-term sustainable chrome production. Since TOMRA Insight was connected to sorting machines here at the start of 2020, the data platform has convincingly proven its effectiveness, TOMRA said. Among the gains made so far are improvements in process monitoring and streamlining, more efficient line-feeding and machine running times, and reduced downtime.

Albert du Preez, Senior Vice President and Head of TOMRA Mining, said: “By accessing information, TOMRA Insight is unlocking new opportunities. Mineral processors can now move from making decisions based on experience and local observations to decisions based on experience and hard facts. This means TOMRA Insight can help reduce waste rock and downstream processing costs, enabling processors to earn more dollars per tonne.”

To build on these benefits, TOMRA Mining is working closely with customers to continuously develop TOMRA Insight. The future will bring the addition of more features and functionalities, which customers will automatically receive as part of their Service Level Agreement.

Multotec solution scrubs up well at Ekapa Minerals diamond plant

A revolutionary new concept in fines scrubbing is proving to be a game changer for Ekapa Minerals at its Combined Treatment Plant (CTP) in Kimberley, South Africa.

The innovation, developed by Multotec Wear Linings, is processing both virgin underground kimberlite as well as tailings for retreatment at the CTP. The solution is effectively a pulping chute that scrubs and washes the re-crushed product after it has passed through the high pressure grinding rolls (HPGR) inter-particle tertiary crushing circuit.

The important advantage here, according to Multotec Wear Linings Projects Sales Manager, John Britton, is that it performs the scrubbing action faster and more efficiently than a traditional rotary scrubber would, and at much lower cost.

Multotec commissioned two of these pulping chutes at Ekapa Minerals in late 2019, where they have been operating consistently and in line with expectations. With the use of patented wave generators, the pulping chute uses the gravitational energy from the slurry flow to create a constant turbulent mixing action that releases the mud, clay and slime sticking to the kimberlite particles.

According to Ekapa Minerals CEO, Jahn Hohne, the pulping chutes are a welcome contribution to the company’s cost saving efforts, and a clear demonstration of Multotec’s expertise in developing value-adding solutions in the mining sector.

“The dual chute pulping plant is ideally suited to de-conglomerating the HPGR cake product and is exceeding expectations in efficiency and effectiveness at over 600 t/h, which is a major relief on the existing overloaded pair of CTP scrubbers,” he said. “The net result is a meaningful increase of up to 20% throughput capacity of the entire processing plant which substantially improves the economy of scale of CTP, feeding directly to the bottom line.”

Britton highlighted the efficiency of the system, which is able to aggressively scrub the material in just three to four seconds as it passes through the chute. This represents just a fraction of the usual retention time in a rotary scrubber, which is three to four minutes, according to the company. He also emphasises the drastic reduction in running cost which the pulping chute achieves.

“From our experience of plant layouts and flow diagrams, it is clear that fines scrubbers are significant contributors to a plant’s capital, operating and maintenance costs,” Britton said. “Scrubbers are equipped with large drives with gears and gearboxes to rotate the drum. They are high consumers of power and require mechanical component maintenance which means higher operating costs.”

Substantial structures and supports are also needed for the scrubber and its drive mechanisms. In designing the pulping chute, Multotec sought a simplified solution, Britton says. In addition to improving scrubbing efficiency, the objective included reducing the cost of replacing scrubber liners and the downtime that this demanded. The cost of replacing the steel shell of a scrubber – which is constantly subject to stress, wear and fatigue – was another cost to be considered.

“The pulping chute, by contrast, is a stationery and much simplified innovation, focused on the scrubbing of fines less than 32 mm in size,” the company said. “Slurry deflectors located at the top end of the scrubbing chute direct at least part of the slurry away from the scrubbing chute floor. This curls into an arched form which flows backwards into the approaching flow of slurry, creating the turbulent scrubbing effect.”

Britton said: “We custom-design the chutes to suit the application and can increase chute capacity to up to 800 t/h. This is achieved with no moving parts, bearings, hydraulic packs or girth gears; the only power required is to supply material and water to the receiving chute. These actions are also required to feed the scrubber, then gravity takes over and provides the required energy.”

Maintenance is also streamlined by designing the chute in segments. Should one segment be wearing more than others, it can be quickly removed and replaced – putting the chute back into operation while the original segment is refurbished as a spare.

Britton says the pulping chute has drawn interest from other diamond producers in southern Africa, Australia and Canada. It can also be applied in commodity sectors such as coal, platinum, chrome, iron ore and mineral sands.

TOMRA’s XRT ore sorting aids recoveries, costs at South Africa chrome mine

One of TOMRA’s X-ray Transmission (XRT) sensor-based ore sorters is helping improve recoveries and lower costs at a South Africa chrome operation.

As South Africa chrome mining operations have increased production in the face of rising demand from stainless steel buyers, the cost of using traditional methods for separating low-grade chromite material, such as dense media separation (DMS), cyclones and spirals, has increased. XRT ore sorting, an established technology in physical separation that has proved extremely effective in mining operations for a variety of minerals, including chrome, is another pre-concentration route they are looking into.

“Its benefits are significant: less complexity in the process, considerably lower costs, higher productivity and profitability – and the added advantage of a lower environmental impact,” TOMRA, a supplier of XRT solutions, said.

The X-ray sensor accurately establishes the density of each particle in the feed, and high-speed pneumatic ejectors separate ore with high chromite content from barren or low-grade ore at throughputs between 60-200 t/h. “The resulting output is a high-grade product that is ready to sell, with no need for additional comminution,” the company said. “It is a dry process that requires no water or reagents, and is frugal in its energy consumption, resulting in a fraction of the capital expenditure and running costs of traditional methods, as well as a smaller footprint.”

Engineering and project management company P2E Consulting has first-hand experience of the advantages of TOMRA’s XRT technology in sorting chrome ore at Eastern Chrome mines, in South Africa. It was looking for a solution to improve the efficiency of the sorting plant and turned to TOMRA.

“We have installed TOMRA sorters on diamond and copper plants in the past and we believe their technology is ahead of their competitors,” Craig Meadway, Business Development Executive of P2E Consulting, said.

P2E Consulting commissioned a TOMRA COM XRT 2.0 sorter to replace an existing drum DMS plant.

“The mine used the DMS plant to produce saleable small lumpy product from the mine’s LG6 Chromite run of mine and dumps at a minimum grade of 38%, but it was very inefficient,” Meadway explains. “The TOMRA XRT sorter has resolved this issue. It is used to upgrade under value material with a head grade of 20-28%, to produce a saleable product at a minimum grade of 38% Cr2O3. It does this efficiently and at a low cost of production.”

The TOMRA COM XRT 2.0 sorter has exceeded Meadway’s expectations, with grades being achieved in excess of 40% Cr2O3 and mass recoveries of 25-30% from scalped waste resulting in chrome-in-tails as low as 12%.

“No other technology has given us such a high recovery rate. Not only that, with TOMRA’s XRT there was no water usage at all, and we didn’t need to spend on expensive reagents, so that we are producing small lumpy product for approximately 50% of the cost compared to a DMS plant,” he said.

The environmental benefits of TOMRA’s XRT solution were also an important factor in P2E Consulting’s choice of technology. “We are looking to introduce greener technologies into the mining industry. The fact that no water or chemicals are used is a major advantage,” Meadway said. “Also, South Africa has major power limitations, and the lower energy consumption when compared to DMS is a huge driving force.”

The ease of operation of TOMRA’s XRT sorters proved to be a further advantage: “It is very easy to use: once the sorter and feed system control philosophy is set up correctly, the plant runs with very little input from the operators,” Meadway said.

TOMRA’s collaborative approach and all-round support was also an important factor in P2E Consulting’s decision to turn to them for this project, according to Meadway.

“We knew from our experience in previous projects that the support from TOMRA is very good, and with the installation of this machine in a relatively new application, it was excellent,” he said. “The local team has bent over backwards to help us make this happen.”

Multotec ready for the mineral processing test

Mineral processing specialist, Multotec used a recent media visit to talk up the testing facilities at the heart of its Technology Division.

The South Africa-based company can carry out a range of testwork with its specialised equipment in Spartan, Gauteng, according to Multotec Technology Manager, Faan Bornman.

“Much of our testwork comes from customers who are in the early stages of project development,” Bornman says.

“They need to understand more about how their minerals or material will separate under given conditions. Often there is not a mathematical model that can predict accurately what they can expect.”

Testwork can reduce project risk significantly, providing a solid foundation for the subsequent design and optimisation of process facilities, Multotec says, with Bornman noting that physical testwork is usually the best way of finding out how particles will behave in a process plant.

The equipment available to Multotec customers includes laboratory-scale wet high-intensity magnetic separators, cyclone rigs, filtration equipment, centrifuges, spiral rigs and a screening research rig. There is even capacity to test water purification methods on mine effluent.

“Extensive test work is especially relevant when a customer is wanting to mine and treat less traditional minerals like lithium or graphite,” Bornman says. “As demand grows for commodities like these, we have had customers bring samples to test how our equipment would perform. In these tests, we trial various methodologies and scientifically record and compare the results.”

The R&D laboratory prepares samples and conducts particle size analysis using equipment such as pressure filters, drying ovens, sieves, shakers, sizers and separating funnels. When chemical analysis is required, samples are sent to outside laboratories.

Bornman said his division also receives enquiries from existing customers when they face challenges: “We research the application of different methodologies to customer material, often leading to the development of a new product or improvements to our existing products,” he said.

“In addition to providing a solution for the customer, we are also able to contribute to the efficiency of the industry as a whole, with an updated and commercialised product.”

Screening

When it comes to tests on mineral screening, a test rig – located at Multotec’s Spartan headquarters – delivers two primary benefits, according to Chris Oldewage, Technology Manager at Multotec Manufacturing. First, it facilitates the in-house development process of screening media products. Second, it allows screening media to be tested against customer requirements to ensure the right solution is delivered.

“The ongoing research and development behind our screening media products give the industry opportunities to optimise efficiencies and recoveries,” Oldewage says. “However, changing anything on a plant brings risk of unexpected downtime. Our screening test rig can considerably reduce operational risks by proving any changes before they are implemented on site.”

In the controlled environment provided by the screening test rig, customers can view the actual performance of screening media products with material from their mining operations, Multotec says, with the company’s testing protocols generating the data necessary for detailed process analysis. This facilitates well-informed subsequent decisions, the company said.

The screening rig is made up of three test platforms: a vibrating screen, a sieve bend and a static drain screen platform. The vibrating screen can conduct classification tests, wet and dry dewatering tests, product development tests and plant screen simulations. The static drain screen and sieve bend screening test platforms are wet classification, drainage and dewatering tests.

Multotec Process Engineer, PJ Pieters, said accurate scaling of a customer’s on-mine process is vital for achieving representative and relevant test results.

“We gather a range of key data from customers on our test work questionnaire,” Pieters said. “This includes their material tonnages, volumes of water, screen sizes in operation and aperture sizes on panels among other information.”

This ensures sample sizes are representative and the tests accurately reflect what is taking place in the mine’s processes. Tests, meanwhile, are conducted in triplicate runs to ensure a sound scientific basis for the findings.

Oldewage said: “By removing the risk that mines face in trying new solutions, our testing capability smooths the way for valuable innovation to improve screening performance.”

The screening test facility at Multotec also includes a small Lucotec screen and a small wedgewire trommel screen, both for small-scale verification test work.

Cyclones

Multotec’s large scale cyclone rig, meanwhile, can test the performance of a range of cyclone sizes, up to 450 mm diameter. Tests related to classification, desliming and dewatering, as well as dense medium separation using density tracers, can be conducted.

Among the benefits to customers is the ability to test large volumes of samples, as the rig includes a 1,750 litre sump and a 6/4 pump, Multotec said. Flexibility is provided by a variable speed drive connected to the pump, to vary the flow rates as required by the cyclone size.

Dry samples usually need to be blended before testing, and wet samples may need to be dried before blending. The resulting samples from the test must also be scientifically prepared for particle size and chemical analysis. The precision at each stage is vital, as bulk samples as large as 200 kg may need to be reduced to as little as 100 g.

The rig’s infrastructure also includes two Multotec vezin samplers, which are compliant with the highest design standards to provide reliable samples, according to Multotec. “These help to minimise the common errors of manual sampling and ensure that the integrity of the sample is retained,” the company says.

In addition to using the test rig to analyses the customer’s process flowsheet – with Multotec engineers identifying where its range of classification and other products can add value – the company also uses the cyclone test rig for its own product development.

“This on-going process has resulted in a range of cyclones that are lighter, more cost effective, environmentally-friendly and energy efficient,” the company said. “They all contribute to helping customers lower their cost per tonne in a low footprint, sustainable plant operation.”

Spirals

Multotec says its spiral test rig has been adapted in response to the industry’s need to re-treat chrome dumps and upgrade ultra-fine chrome.

Again, located at the company’s headquarters in Spartan, the rig allows eight to 10 different spirals to be erected at a time.

Jeantelle Rust, R&D Engineer at Multotec Process Equipment, said: “With the drive to process tailings in the chrome sector, we have been running tests on a more compressed spiral with a reduced pitch. This reduces the velocity of the very fine particles.”

This configuration works particularly well when dealing with fine material, hence its application in tailings, Rust said. The spiral could offer a cost-efficient way of separating ultra-fine chrome material and recovering valuable product, according to the company.

Rust said: “Such a solution presents an attractive commercial proposition to industry and will also address environmental concerns presented by tailings dumps.”

Using a “mouth-organ product box”, the material being tested on the spiral rig is split into eight product fractions, not just the usual three for product, middlings and tailings. This helps optimise the mass balance for reporting purposes, according to the company.

The spiral test rig has also been used to evolve designs that deal with coarser material, Multotec said. “Customers were looking for a solution to the ‘beaching’ of coarse coal product on the spiral’s surface, for instance,” it explained.

Rust said: “We were able to modify the angles and diameter of the trough to address this challenge. Our ability to make small adjustments to the equipment, and to test material repeatedly at full scale, is the key to finding practical solutions.”

Multotec has also conducted research for producers of mineral sands where head grades were steadily dropping. This necessitated the treatment of larger tonnages, requiring higher capacity spirals.

“Space constraints on the customer’s site meant that adding spirals to their process was not an option,” Rust said.

“Wider spirals were thus tested for higher throughput, with different angles to minimise losses.”

 

Forte Demolition goes to work on chrome pelletising plant in Rustenburg

Forte Demolition Solutions, a subsidiary of surface materials handling expert SPH Kundalila, has started demolishing a chrome pelletising plant in Rustenburg, South Africa, following a recent turnkey contract award.

Forte says it is tackling the project with its specialised range of mechanical dismantling and demolition equipment.

Graeme Campbell, Group Commercial Operations Manager at SPH Kundalila, said: “Our investment in this equipment is substantial, making us the ideal partner for mines and other operations who need to address closure in a safe and sustainable manner.”

The plant to be demolished includes several multi-storey structures, conveyors, steel frames and concrete work, as well as large, heavy componentry, according to the company.

Campbell emphasised that Forte Demolition is one of few companies in South Africa with the necessary assortment of fit-for-purpose machinery and attachments. These ensure the cutting and breaking process is safe and efficient, allowing many components to be carefully dismantled for resale purposes.

“Among the factors behind our cost effectiveness is that we can shorten customers’ timeframes,” he said. “For example, our precision cutting is done by a shear attachment on an excavator. The power of hydraulics – combined with our specialised technology – means that everything is much quicker and safer.”

Equipment that is being employed on the pelletiser site includes a pulveriser for concrete demolition. It breaks concrete into small pieces that can be used as backfill on site, alleviating the need for transporting large concrete chunks to special dumping sites. Other specialised demolition attachments include grapples, hammers and buckets.

High levels of safety are ensured by an integrated safety, health, environment and quality management system, according to Brad van Niekerk, Project Manager at Forte Demolition Solutions.

“Safety is our key priority, which is enhanced by the closely supervised use of our mechanical equipment,” van Niekerk says. “This ensures that workers are not placed at risk by being too close to dangerous working environments.”

He notes that each project is planned and monitored by a skilled professional team, which takes the safest demolition approach. This is also aligned with customer standards to ensure full compliance with corporate and regulatory requirements. A 51% black-owned business and Level 2 B-BBEE contributor, Forte Demolition Solutions operates in South Africa through its offices in Fochville, Rustenburg, Stilfontein and Carletonville.