Tag Archives: ore sorting

Hatch to move forward with process plant DFS for Magnetite Mines’ Razorback iron ore project

Magnetite Mines Ltd says it has appointed Hatch to complete the process plant section of the Definitive Feasibility Study (DFS) on its Razorback iron ore project in South Australia.

This, Magnetite Mines says, is an important contract award for the company and represents the largest component of the DFS expenditure and completes the appointment of major engineering roles.

Hatch’s scope builds upon the process plant design and AACE Class 4 Estimate that was completed as part of the prefeasibility study (PFS). This study supported the declaration of a maiden ore reserve of 473 Mt based on 12.8 Mt/y plant throughput and 2 Mt/y of high-grade concentrate. It also included plans to incorporate ore sorting technology.

Key areas of work for Hatch on the DFS include:

  • Designing a metallurgical test program to confirm comminution and processing properties;
  • Improving and defining the process flow sheet based on metallurgical results and optimisation reviews;
  • Developing the mechanical, piping, electrical, structural, and civil engineering to support an AACE Class 3 Capital Cost estimate; and
  • Providing construction and procurement input to develop the contracting strategy for execution.

At completion of this scope of work, Hatch will provide design deliverables and cost estimate, developed in line with the AACE guidelines for a Class 3 estimate (18R-97) for the process plant, Magnetite Mines says. The deliverables will be to a standard and level of detail that will allow Magnetite Mines to include them in a tender package to obtain proposals for a predominantly fixed price design and construct contract or an engineering, procurement and construction management contract on market terms for procurement of the process plant.

Claude D’Cruz, Director – Metals, Australia-Asia for Hatch, said: “Following the successful delivery of the previous study work, Hatch is very excited to continue our association with Magnetite Mines through to the DFS and to be able to apply our considerable magnetite processing experience to the development of Razorback.”

Magnetite Mines Limited Executive Chairman, Peter Schubert, said: “The PFS confirmed the process plant scope and the attractiveness of producing high-grade iron ore products at a competitive cost from the first stage of development of the company’s extensive iron ore resources. The DFS will undertake more detailed engineering and generate the tender packages for construction, supporting a decision to mine.

“This continues our strategy to carefully and systematically progress the project with the guidance of best-in-class technical consultants. We look forward to working with Hatch, as we develop Razorback into a successful operating iron ore business.”

Tungsten West set to bring Hemerdon tungsten-tin mine back into production

Tungsten West, the mining company focused on recommencing production at the Hemerdon tungsten and tin mine in Devon, England, has announced its intention to proceed with an initial public offering on London’s AIM market.

The company has conditionally raised £39 million ($53 million) before expenses, with plans to debut on the bourse on October 21 with a market capitalisation of approximately £106.2 million.

The net proceeds of the offer, together with the $49 million project financing from a fund managed by Orion Resource Partners, will be used to, among other things, execute the planned capital expenditure and corporate commitments of £44.6 million for improvement works at the Hemerdon Mine, bringing it back into commercial production.

Hemerdon is, Tungsten West says, the third largest tungsten resource globally, as well as being a previously producing mine that was operational from 2015-2018. Tungsten West purchased the Hemerdon Mine in 2019, and has since completed a bankable feasibility study that demonstrated an extensive reserve of approximately 63.3 Mt at 0.18% W and 0.03% Sn, as well as 37.4 Mt of saleable aggregate material. The company estimates that the life of mine is currently 18.5 years with the opportunity to extend this through future investment.

The mine already has the majority of its infrastructure in place, with previous owner Wolf Minerals Ltd having invested over £170 million into the development of the mine and its processing facilities, which include an open-pit mine, mineral processing facility and mine waste facility, the company says. With a substantial amount of existing infrastructure, the development costs associated with re-starting the mine are estimated to be £44.6 million. This existing infrastructure also means that the rebuild is only expected to take 12 months, with parts of the restart project already underway.

Having acquired the mine out of a receivership process, Tungsten West completed a significant amount of work to enable it to understand and address the issues historically experienced by Wolf Minerals, including a 6,113 m geological exploration drilling program and several technical studies. The company has identified the past issues experienced by Wolf Minerals that required rectifying.

“One of the main issues was a poor mineral process route design, with several items of equipment, particularly in the front end of the plant, causing plant downtime and hindering the recovery of the tungsten and tin minerals,” Tungsten West says. “Tungsten West has therefore designated a material proportion of its rebuild costs to modifying and updating the front-end of the processing plant. This will include replacing the existing crushing circuit with new duty and standby primary jaw crushers and secondary cone crushers.”

In addition, the introduction of X-ray Transmission ore sorting, which the company previously carried out tests on with TOMRA Mining in Germany, substantially reduces processing costs by rejecting around 70% of the ore fed to the sorters, it says.

Further upgrades to the plant commenced by the previous operator will be completed, including the dense media separation feed stockpile where 24 hours of surge capacity will be installed, decoupling the front-end of the plant from the concentrator circuit.

“Through these actions, the company expects plant operating time to improve from circa-53% under previous operatorship to the industry standard of circa-81% under Tungsten West,” Tungsten West says.

Tungsten West has identified further opportunities for by-product cash flow through the production and sale of aggregates. A new aggregate plant will be fed with ore sorter rejects and with the waste streams from the processing plant. The business plan is to sell to local aggregate consumers, such as GRS, providing them with a stable, long-term and sustainable source of these materials.

The company says it has implemented a number of initiatives to ensure a minimal impact on the surrounding environment and local community. These include optimising the plants low frequency noise to ensure minimal environmental impact and a fully cash funded £13.2 million restoration bond.

Max Denning, CEO of Tungsten West, says: “With the proposed £39 million raise announced today, and the £36 million funding package from Orion, we will be fully funded for the development of Hemerdon back into production. We look forward to welcoming new investors into this compelling business and working with all our stakeholders to ensure that the newly reinvigorated Hemerdon mine is a beacon of mining excellence in the UK.”

Vast sees path forward at Manaila with help of TOMRA’s XRT ore sorting solution

Vast Resources says it is continuing to evaluate the recommencement of production at its Manaila polymetallic mine in Romania and, as part of this process, has been working with TOMRA to assess the suitability of X-ray Transmission (XRT) ore sorting technology to optimise the mine’s production profile.

The assessment has demonstrated, to date, that by installing an XRT machine at the plant to pre concentrate ore at the pit, the technology would be highly effective for three main reasons:

  • A reduction in transportation costs as improved mass reduction would significantly reduce the material being transported from the mine to the processing plant;
  • A reduction in processing costs due to reducing the throughput at the plant; and
  • Higher-grade product being delivered to the plant.

It is anticipated that processing and transportation costs could be reduced by up to 55%, according to Vast.

“This cost reduction could have a dramatic impact on the mine’s financial performance,” the company says.

Samples from both types of mineralisation at Manaila, massive sulphide and disseminated sulphide, were sent to the TOMRA Test Centre in Wedel, Germany, to ascertain improved mass reduction and grade upgrade potential. Both mineralisation types showed amenability to the XRT process with metal content recovery on the massive sulphides at 95.4% for copper, 93.6% for lead and 95.2% for zinc in 71% of the mass, the company explains. The disseminated sulphides returned a metal content recovery of 84.2% for copper, 67.2% for lead and 84.4% for zinc in 35% of the mass.

The combined results show that 93.1% of copper, 82.2% of lead and 92.4% of zinc metal could be recovered in 45% of the mass when mining the polymetallic ore on a ratio of three tonnes disseminated sulphide to one tonne of massive sulphide, being the typical historical ratio of mining at Manaila.

Andrew Prelea, Chief Executive Officer of the Vast Resources, says: “These results clearly underpin our view that Manaila is economically viable, and the management team are considering various mine plan scenarios of bringing Manaila back into production.”

The 138.6 ha Manaila-Carlibaba exploration licence contains a JORC 2012 compliant measured and indicated resource of 3.6 Mt at 0.93% Cu, 0.29% Pb, 0.63% Zn, 0.23 g/t Au and 24.9 g/t Ag with inferred resources of 1 Mt at 1.1% Cu, 0.4% Pb, 0.84% Zn, 0.24 g/t Au and 29.2 g/t Ag. Comprising the Manaila polymetallic mine (currently on care and maintenance) and the Carlibaba extension project, Vast intends to establish a larger mining and processing facility at Manaila-Carlibaba which would eliminate the need for costly road transport of mined ore to the existing processing facility located at Iacobeni, around 30 km away.

Preliminary studies by the company indicate the potential for a new open-pit mine to exploit mineral resources to a depth of some 125 m below surface, and to simultaneously develop a smaller higher-grade underground mine below the open-pit mineral resources.

TOMRA XRT ore sorting test work delivers the goods at Kutcho’s copper-zinc project

Higher head grades and recoveries, a reduction in run-of-mine material reporting to the milling and flotation circuit, a smaller tailings management facility, and lower power and water demand are just some of the benefits to have come out of ore sorting test work at Kutcho Copper’s copper-zinc project in British Columbia, Canada.

Recent bulk sample test work was conducted to determine the effectiveness of using ore sorting technology from TOMRA Sorting Mining to improve the processed grade and reduce the mill feed tonnage of mineral resources at the project.

ABH Engineering Inc and TOMRA were commissioned to undertake this work to establish the amenability of Kutcho’s Main and Esso deposits to ore sorting using an X-ray Transmission (XRT) sensor. Two phases of test work, including a representative 0.75 t bulk sample derived from drill core, were undertaken at TOMRA Sorting Mining in Germany under the supervision of ABH Engineering.

“The ore sorting process helps concentrate the metals of commercial interest from the Kutcho deposit, which are principally associated with high density sulphide minerals,” Kutcho explained. “Rocks are individually scanned, and low grade (low density) waste material is selectively diverted away from downstream processing using compressed air jets. Preliminary test work on the sensitivity of the ore to a XRF sensor was also undertaken.”

The bulk sample tests conducted on a production-scale XRT ore sorter indicate that approximately 17% of the ROM material will be <12.5 mm in size and would therefore bypass the ore sorter and report directly to the milling and flotation circuit. Of the >12.5 mm feed, some 15% of the material reporting to the ore sorter was detected by the XRT sensors as being low grade or waste and will be rejected by the ore sorter, thereby reducing run-of-mine material reporting to the milling and flotation circuit by 13%. The overall recovery of metal (copper, zinc, silver and gold) reporting to the ore sorter is in the order of 99% (ie less than 1% of the metals of interest will be rejected by the ore sorter), Kutcho said.

Pre-sorting of the run-of-mine material by the ore sorter has the potential to reduce milling and flotation operating costs corresponding with the 13% rejection of low-grade material, it says. The commensurate increase in the head grade of the ore reporting to the flotation circuit has the potential to also result in improved metallurgical recoveries in the flotation circuit.

Additionally, it is anticipated that potential savings in capital and operating costs related to the smaller milling and flotation circuit will offset the costs associated with the ore sorter, according to the company. Savings will also be achieved by a reduction in the size of the tailings management facility. The optimally sized ore sorter reject waste material could be used as cemented rock backfill in the underground mines at both the Main and Esso deposits, resulting in further potential cost savings, Kutcho said.

Environmental benefits accruing to the project because of the introduction of ore sorting technology include a lower power and water demand, and a smaller tailings management facility, the company concluded.

Earlier this month, Kutcho said in a feasibility study progress report that it was considering open-pit mining for the majority of the Main deposit at Kutcho, allowing the company to capitalise on the high-grade, near-surface mineralisation, resulting in lower operating costs than underground mining. The remainder of the Main deposit and all the Esso deposit will continue to be evaluated assuming underground extraction by longitudinal longhole open stoping, it said.

The ore sorting test work was also being incorporated into the feasibility study design.

Steinert XRT ore sorter testing shows promise at Northern Minerals rare earth project

Northern Minerals Ltd has progressed its ore sorting project enhancement initiative with the commissioning and testing of the Steinert sorter system, and is now producing ore sorted material and converting this to a 30% total rare earth oxide (TREO) concentrate in its’ Browns Range beneficiation plant in Western Australia.

Northern Minerals’ CEO, Mark Tory, said: “The construction, commissioning and testing of the ore sorter circuit marks another milestone in the development of the Browns Range project.

“The positive bulk sample tests confirm the effectiveness of the ore sorting circuit on the Wolverine ore to significantly increase the head grade to the mill which is expected to result in higher production rates and lower operating costs for a full-scale operation at Browns Range.

“It’s also pleasing to see the initial ore sorting tests the Banshee ore showing promise which, if shown to be effective in future tests, has potential to significantly increase the Browns Range mineral resource estimate.”

He added: “Being able to test and operate the ore sorting circuit in conjunction with the pilot beneficiation plant is providing extremely valuable data that you just can’t get from small bench-scale tests and this will feed into our feasibility study for a potential commercial scale heavy rare earth operation at Browns Range.”

The ore sorter system was constructed during 2020 and 2021 and commissioned in June 2021. The sorter that was installed is a 2-m wide Steinert sorter that uses X-ray Transmission (XRT) and laser detectors to identify rare earth mineralisation.

The sorter has been run over two test campaigns, which included 41 test runs processing 5,300 t of ore from the run of mine stockpiles largely coming from Wolverine ore, and five test runs on Banshee ore that was bulk sampled from a surface costean that provided 285 t of Banshee ore.

The tests have confirmed that simultaneous sorting of two size fractions is possible on the sorter, allowing a single machine to sort both sortable size fractions (10 mm-25 mm and 25 mm-75 mm), Northern Minerals says. The sortable fraction (>10 mm material) of Wolverine ore can be successfully sorted (90% TREO recovery in 50% of the mass) and, when combined with non-sortable fines, achieves a 45% grade increase to the mill and over 95% TREO recovery when feeding a 0.9% TREO ore.

The sorter system is now being run to produce feed for the beneficiation plant and 4,479 t of Wolverine ore have been processed through the ore sorter circuit to the end of August. Processing of the Wolverine ore sorted material in the beneficiation plant has resulted in better recoveries in the magnetic separation plant and flotation plant compared with feeding unsorted ore, the company says. A bulk sample of 50 t of 30% TREO rare earth concentrate has being produced for test work by facilities identified with likely future capability and capacity to process the heavy rare earth xenotime concentrate produced at Browns Range.

Bulks sample tests have highlighted some key factors to consider for ore sorting that cannot be determined at bench scale using vendor equipment in laboratory settings. Understanding the impact of these factors is critical to including an ore sorting circuit in a full-scale processing facility.

Initial sorting tests of the Banshee ore have shown that the highly oxidised surface material contains a large fines fraction and that the grade of the sortable fraction (ie >10 mm) can be doubled recovering more than 60% of the TREO in 25% of the mass. An additional bulk sample is being extracted from deeper in the costean and three diamond drill holes are being drilled for further test work.

The bulk ore sorting test work is a key input for the full-scale beneficiation plant feasibility study currently underway, which will also leverage off the substantial technical, operational and economic data from the R&D test work at the Browns Range Pilot Plant since 2018, the company says.

Element 25 targets Butcherbird upgrade with STEINERT KSS ore sorters

Element 25 Ltd has acquired two STEINERT 2-m-wide KSS ore sorters fitted with multiple sensors that are now installed at its Butcherbird manganese project in Western Australia.

The sorters will be used to upgrade the high-quality manganese concentrate for export markets, STEINERT says.

The Butcherbird operation has a proven and probable manganese ore reserves of 50.55 Mt at an average grade of 10.3% Mn for 5.22 Mt of contained manganese.

Element 25 plans to use the STEINERT KSS sensor-based sorters to upgrade the washed feed material to an average grade of >32% Mn, STEINERT says.

The miner has already shipped its first consignment of ore and the second is scheduled to be loaded at Port Hedland, in Western Australia, in late August. Current annual production is estimated at 365,000 t of manganese ore concentrate with a 40-year mine life for Stage 1 of the operation.

Element 25 previously said Butcherbird is ideally placed to feed potential demand, with advanced flowsheet development work undertaken in 2019 and 2020 confirming a simple, unique, ambient temperature and atmospheric pressure leach process for Element 25 ores which, when combined with offsets, will target the world’s first Zero Carbon Manganese for EV cathode manufacture.

Scantech launches GEOSCAN GOLD to help digitalise and control ore quality

Scantech International Pty Ltd has released GEOSCAN GOLD, a premium elemental analyser that, it says, uses the highest specification PGNAA (prompt gamma neutron activation analysis) technology available.

The analyser, which builds on Scantech’s GEOSCAN-M high-performance elemental analyser, provides previously unattainable levels of risk-free, real-time measurement performance to the resources sector to help digitalise and control ore quality, according to the company.

GEOSCAN GOLD provides high-quality, real-time elemental analysis for conveyed flows where precision and short measurement times are essential for optimal control. This makes it ideal for bulk diversion (bulk sorting) and fine control where elements at parts per million levels need to be measured or determined from proxies such as gold, platinum group elements, silver and toxic contaminants (eg mercury, cadmium, chlorine, etc), Scantech says.

The analyser incorporates a high performance proprietary detector array for a “better, cleaner spectrum” at lower concentrations for superior element recognition. The array overcomes limitations of conventional, low efficiency detection systems, according to Scantech. It can also operate at extremely high count rates with negligible pulse pile-up.

“This innovation vastly improves the signal to noise ratio and spectral peak resolution, enabling elemental detection at lower levels,” the company said.

Just some of the advantages of GEOSCAN Gold that Scantech highlighted include:

  • An ultra-compact design that can install between standard idlers;
  • Unmatched proven performance;
  • Operational at completion of commissioning;
  • Customised calibrations;
  • Three models cater for belts 600 mm to 2,400 mm and bed depths to 530 mm;
  • No contact with material or conveyor belt;
  • No sampling necessary during normal operation;
  • No wear parts, therefore, low maintenance requirements;
  • Optional customised SUPERSCAN console;
  • Interface to most process control systems; and
  • Proven short paybacks in many applications (bulk diversion, blending, monitoring, feed forward, etc) to optimise plant performance.

The company says GEOSCAN GOLD measures elements in primary crushed rock in conveyed flows at <100 t/h to >10,000 t/h irrespective of belt speed, particle size, mineralogy, dust, moisture, or segregation/layering,

It covers most elements from carbon onwards in the periodic table, including gold, over various measurement times and concentration levels. It can also analyse selected elements to below 1 parts per million, and even register accurate results where conveyor belts contain chlorine or steel cords.

It can register gold directly over 5-10 minute increments and other elements, including proxies for gold (eg sulphur, copper, etc), with high precisions over each 30 seconds of flow.

Measurement data is used concurrently for various applications: bulk sorting, ore blending, ore reconciliation, ore tracking, feed forward control, metal accounting, etc.

“GEOSCAN GOLD is the new standard in representative, real time, conveyed material measurement using Scantech’s Rocks2data customisation module,” the company said. “Successful performance is already proven in many challenging bulk ore sorting applications in base metals and PGMs. It builds on the very successful, world-leading GEOSCAN-M with over 100 installations in the minerals sector in more than 10 commodities. Paybacks are in a few months and sometimes weeks. Non-contact design minimises maintenance and remote access ensures trouble-free operation and high data accessibility.”

New Gold to collaborate with MineSense in underground ore sorting move

MineSense is gearing up for a move underground with the help of New Gold and its New Afton gold-copper mine in British Columbia, Canada.

The Vancouver-based technology company has already established and proven its ShovelSense technology for the open-pit mining sector, with its X-ray Fluorescence (XRF) sensor-based system now operating on shovels, wheel loaders and excavators on a commercial basis across six operating mines. This includes large installations at Teck’s Highland Valley and Copper Mountain’s copper operations in BC, as well as one ShovelSense unit at the Antamina copper operation in Peru.

Designed for operation in extreme environments and retrofits on any existing mobile equipment, ShovelSense units come equipped with a human machine interface and proprietary algorithms that measure and report ore grade/characteristics. They can also connect directly to fleet management or other existing control software systems, enabling mine operators to reconcile geological block models with actual ore grade data.

Having finetuned the system for above-ground operations, the company is now embarking on its underground move, according to MineSense President and CEO, Jeff More.

A trial of the underground ShovelSense system at New Gold’s New Afton mine is first up to complete product development. The company will be installing a unit on a Cat R1600G LHD for this step. This will be followed closely by installation at a “large entity” in Chile – with More anticipating start up in the September or December quarter.

The development agreement with New Gold at the BC-based mine is looking to trial and finetune the system for underground operations, with More confident the ShovelSense system will stand up to the test.

“The core technology – all of the algorithms, software, hardware – is the same as ShovelSense for open-pit mining,” More said. “It is the ‘application package’ – looking at how we can attach the unit to the machine and protect it in an underground environment – that is what we have to test out. The design for this is already complete; it’s just a matter of trialling it.”

New Afton represents a good test for the system.

New Afton is Canada’s only operating block cave mine, with the New Afton deposit part of a larger copper-gold porphyry district in the region. The operation regularly mines 15,000-16,000 t/d of ore and waste, with the majority of this currently going to the mill.

The company has already pursued “ore segregation” projects to boost the grade of material being fed through to the processing side, but the move into the higher-grade C-Zone in 2023-2029 will place an even greater emphasis on ore/waste boundaries and milled tonnes at the operation.

At the same time, the ShovelSense deployment at New Afton will represent the first time MineSense has sent a unit into a mine that has so much payable gold, with most operations the company has worked on being primarily base metal-oriented.

In 2020, New Afton produced 64,000 oz of the yellow metal, along with 32,659 t of the red metal.

“This will be the first time we’re touching gold at this level; we have other mines that have payable gold but not at that level,” More explained.

In New Afton’s case, sampling and historical data has proven that the orebody’s copper and gold ratios tend to be consistent and unchanging over the long term. With this knowledge, New Afton has used technology in the past to determine the copper value and make ore/waste production decisions. ShovelSense allows New Afton to move the ore/waste production decision to the drawpoint, according to MineSense. This reduces mixing and blending during the crushing and conveying circuit which can homogenise the material to the point where it is not worth segregating.

Trialling new technology such as this is nothing new for New Afton.

The operation already uses automated loading through Sandvik’s AutoMine solution, is employing electrification with the use of Sandvik and MacLean Engineering battery-powered mobile equipment, and, in the process plant, has Gekko Systems’ highest volume InLine Pressure Jig IPJ3500 to improve gravity concentration.

More says the ShovelSense unit could be in the Cat LHD bucket at New Afton in August, with the machine then going through an above-ground trial ahead of the underground transition at the end of September.

“By early Q4, we should have completed the pilot,” he said.

Magnetite Mines plots Razorback DFS path that includes ore sorting

Magnetite Mines is preparing to commence a definitive feasibility study at its Razorback iron ore project in South Australia after receiving positive results back from a pre-feasibility study (PFS).

The PFS supports declaration of a maiden ore reserve of 473 Mt based on 12.8 Mt/y plant throughput and 2 Mt/y of high-grade concentrate, but it has opened the door for two other options.

Process plant optimisation, for instance, could see a nominal 15.5 Mt/y feed using three grinding stages, three stage magnetic separation and flotation to generate a premium-grade magnetite concentrate with 67.5-68.5% Fe content. And a “Head Grade Improvement Case”, based on higher mining rates with a head grade upgrade from selective mining or ore sorting, could see around 2.7 Mt/y of high-grade concentrate produced.

Razorback would involve initial capital investment of $429-$506 million for a post-tax internal rate of return of 14-33%. This is based on the range of throughput and concentrate production options, in addition to 62% Fe iron ore prices of either $110/t or $150/t.

Magnetite Mines said preparation for a prompt commencement of a definitive feasibility study is well advanced with further drilling, test work, metallurgical investigation and engineering workplans in progress.

Magnetite Mines Limited CEO, Peter Schubert, said: “The PFS is a significant milestone for the company, and defines our optimised go forward scope, which has been developed following rigorous and methodical testing of various options. The resulting scope meets our objectives of practical scale, capital efficiency, attractive returns, high quality product and an expected low emissions footprint.

“This small-scale start-up allows for a practical development of a long life, high quality business with a targeted date for first ore on ship at the end of 2024.”

The mining strategy involves a simple, small-scale mining operation, using mining contractors at start-up to simplify development and leverage the advantages of low strip ratio and short, flat hauls due to orebody geometry and outcropping nature, it said.

“The potential for selective mining is a key criterion and a simple truck and shovel operation was selected as a flexible, reliable and selective method of resource extraction,” the company said. “Bulk methods such as electric rope shovels, in-pit crushing and conveying and continuous miners were investigated but not selected.”

The selected fleet used a single 350 t excavator as primary unit with wheel loader back-up loading medium class (150-190 t) rear dump trucks. The 350 t excavator class was chosen as the maximum size of excavator that can achieve the 1 m of selectivity required to take advantage of the orebody characteristics. Ancillary gear has been sized to a size class appropriate for the excavator productivity and road geometry.

“During the definitive feasibility study, as further geological drilling and geo-metallurgical testing is undertaken, the fleet mix will be reassessed match capacity requirements once selective mining strategies are finalised,” the company said.

During the PFS, investigations and modelling showed there is significant potential in accelerating mining activities and realising higher plant feed grades, from some combination of accelerated and selective mining, stockpiles strategy and/or ore sorting, the company said.

Magnetite Mines has been investigating the potential application of a NextOre magnetic resonance analyser (MRA) with ore sorting technology to the Razorback resource. The use of the MRA allows for a high throughput, high accuracy bulk sorting application that is typically added to the front-end of a processing flow sheet to divert waste ores away before processing, it said. “This has the effect of improving mining grades by pre-concentrating the ore that will be subject to processing, whilst rejecting significant tonnages of low-grade material to tailings via a diversion method such as a chute flop gate or dead box diverter,” the company added.

In October, the company announced it had entered into an agreement with NextOre to supply a mobile bulk ore sorting plant using a magnetite resonance sensor for a trial of the NextOre technology. While the bulk trial was originally scheduled for later in 2021, NextOre and the company have agreed to reschedule this trial until later in the development schedule to allow for the results of planned infill drilling and metallurgical test work that are part of the planned definitive feasibility study to be incorporated in the bulk trial design, the company said.

To assess the impact of improved head grades in the PFS, meanwhile, results from an ore sorting case have been developed, using an increased mining rate and the block model used for reserves, then applying the previously released ore sorting results to generate improved plant head grades and mass recoveries.

“These results are consistent with the analysis earlier in the year on the discrete mineralised bands of the deposit and the gridded seam model,” it said. “Due to these encouraging results, the go-forward case for Razorback will be based on the higher head grades available from selective mining and ore sorting, which will be investigated further with comprehensive infill drilling of the Razorback orebody planned and designed to inform a selective mining schedule to definitive feasibility study standards.”

For the PFS, in addition to the test work completed as part of the 2013 PFS and additional high resolution DTR (Davis Tube Recovery) test work, a comprehensive mineralogical test program was completed to better understand the mineralogical composition of the Razorback and Iron Peak deposits, complementing the existing data from the previous test work program. This was informed by the results of the 2013 PFS study, which was completed for a two-module processing plant for a total of 6.2 Mt/y, and an optimised business case for a third module bringing it to 9.3 Mt/y.

Designed by the company’s process engineering consultants, the test work was used to improve the flowsheet. The flowsheet in the 2019 scoping study had three stages of grinding, three stages of magnetic separation and a final cleaning stage with a hydro separator producing final magnetite concentrate at a grind size of a P80 of 25 μm. This is a widely used, low risk flowsheet, but has significant power requirements and generates a very fine magnetite concentrate with potential filtration and product use issues, the company said.

The company has now generated a preferred flowsheet and plant layout for the PFS, which has significant advantages in efficiency and separation over the conventional configuration used in the scoping study estimates, it said. The inclusion of fine grinding and flotation allows efficient production of high-quality concentrate. The final scale of the preferred go-forward option is plant feed of approximately 15.5 Mt/y with ability to process up to 20% DTR with a capacity of up to 3.1 Mt/y concentrate.

Wescoal after RoM upgrade with Acrux, IMS Engineering XRT ore sorting solution

Acrux Sorting Technology has announced that its advanced sensor-based sorting technology is to be deployed at a Wescoal Holdings Ltd-owned coal mining operation in South Africa.

Acrux subsidiary, Acrux Sorting Coal (ASC), has signed a coal beneficiation agreement with two wholly owned subsidiaries of Wescoal, whereby ASC will deploy advanced sensor-based sorting technology to upgrade lower-grade coal from the mines.

Under the agreement, ASC will provide a fully funded turnkey crushing, screening and sensor-based sorting solution centred around advance dual-energy X-ray Transmission (XRT) unit to process run of mine (RoM) coal.

The plant is to be designed, constructed, commissioned, operated and maintained by IMS Engineering Limited, Acrux’s partner on such ore sorting projects. IMS Engineering is a subsidiary of Germany-based HAZEMAG & EPR GmbH.

ASC’s sorting solution offers significant economic benefits as coal resources can now be upgraded to be included as a saleable product, which will reposition the mines along the cost curve, it said.

Paul Bracher, Managing Director of IMS, said: “The XRT technology has proven its ability to upgrade RoM coal through rejecting material that has sulphur or ash content that exceeds programmed parameters.”

The solution will also have a positive environmental impact as no water is used during beneficiation, and the carbon footprint is reduced through the optimisation of transportation and materials handling.

Wescoal’s Executive Director, Thivha Tshithavhane, said: “This sorting technology solution will enable us to impact on ESG, while creating shareholder value from optimising our coal resources at no capital investment.”

Sean Browne, ASC’s Chairman and Group Founder, added: “Partnering with Wescoal underlines our commitment to driving sustainable innovations that reduce the environmental impact of mining.”