Tag Archives: Tin

Tungsten West makes EPCM progress at Hemerdon as TOMRA XRT ore sorters hit the road

Tungsten West has named Fairport Engineering Limited as its engineering, procurement and construction management (EPCM) contractor at the Hemerdon tungsten-tin project, in the UK, as well as confirmed it was soon expecting to receive seven X-ray Transmission (XRT) sensor-based ore sorters from TOMRA.

Since successfully listing on the AIM Market of the London Stock Exchange, Tungsten West has been advancing the development of Hemerdon, which is one of the most advanced mining projects in England and is expected to be a key future global supplier of tungsten and tin.

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.

On top of the ore sorters, Tungsten West said the rest of the long-lead items had been ordered and were scheduled for delivery within the company’s timetable. It plans to recommence mining this year.

The upgrade and refurbishment of the existing processing plant at Hemerdon is centred around the optimisation of the existing concentrator circuit as well as the introduction of a new crushing and screening circuit that will then feed into a new XRT ore sorting stage. These upgrades will streamline processing, minimise plant downtime and improve recovery rates, according to the company.

After significant test work, Tungsten West engaged TOMRA to supply the seven units that are required to treat the run of mine throughput. This consists of six duty and one standby units. Orders and deposits for these units were placed in 2021 and the units have now been delivered to the UK and await final transfer to Hemerdon where they will be installed in the front end of the processing plant.

On top of this, six new screens and 11 vibrating pan feeders have been ordered from Vibramech of South Africa at fixed prices. These will replace the existing large screens, which caused the low frequency issues, and were a key contributor to plant downtime under Wolf Minerals – the previous owner of Hemerdon. Delivery is expected in the June quarter of 2022.

Max Denning, Tungsten West CEO, said: “We are extremely pleased with progress at site, particularly the onboarding of Fairport Engineering to undertake the detailed design and construction of the project. We are looking forward to working with Fairport as we move towards restarting full production at Hemerdon, with a substantially improved processing route, through the introduction of XRT ore sorting and upgraded processing equipment. The company has assembled a strong projects and operations team, and we remain confident in our progress.”

TOMRA Mining’s ore sorting solution helps Renison tin mine do ‘more with less’

TOMRA Mining and its X-ray Transmission (XRT) technology has, the company says, provided an effective solution for the extreme conditions at the Bluestone Mines Tasmania JV (BMTJV) Renison tin mine in Tasmania, Australia, with sensor-based ore sorting solution unlocking significant value and delivering environmental benefits.

The Renison mine is 50% owned by Metals X through the BMTJV, and is the only major tin mine in production in Australia with a mining rate of close to 1 Mt/y, according to TOMRA. While slated capacity is 1 Mt/y, the concentrator is restricted to 750,000 t/y.

The mine’s extreme humidity and highly acidic processing water (pH around 4.5) create unique challenges for the sorting process, the equipment and waste management, according to TOMRA.

A complex flowsheet

The underground mine operates a primary crushing system before the material is transported to the surface through a shaft. Once there, it enters the pre-concentration plant, where it undergoes a three-stage crushing, screening and cleaning process. The particles are split into two fractions – 10-25 mm and 25-60 mm – which are fed into two TOMRA XRT sorters. The output consists of two streams: the product, which is transferred to the wet plant, and the waste, which is fed into a TOMRA EM sorter to separate acid-forming sulphides from this waste stream.

In the wet plant, the product goes through primary grinding followed by bulk sulphide flotation. The tailings are processed downstream to concentrate the cassiterite tin mineral through gravity concentration; gravity tails are further treated via desliming and tin flotation. The combined concentrates are fed to a leaching circuit to remove carbonate minerals. After a final wash stage, the concentrate is de-watered and dispatched.

BMTJV approached TOMRA to address two key requirements at the plant. The first was the need to upgrade the tin feed to the plant, as Ben Wraith, Principal Project Metallurgist at BMTJV (pictured below), explained: “The Renison tin operation wanted to achieve economies of scale, putting more tonnes through the front end of the plant without upgrading the back end downstream – we wanted to do more with less.”

The second requirement was to address the environmental issue of removing acid-forming sulphides from the waste.

Following site visits and extensive discussions with BMTJV’s teams, TOMRA proposed a solution that addressed the tin feed quality with two COM Tertiary XRT 1200 sorters and the waste issue with a COM Tertiary EM 1200 sorter. A team from BMTJV visited the TOMRA Test Center in Sydney, Australia, where they observed what the XRT sorter operating at capacity is capable of.

Gavin Rech, Technical Manager at TOMRA, said: “Our XRT stands out for the high spatial and density resolution and its ability to do contrast sorting, identifying fine high-density tin inclusions in the ore with an accuracy that has no equal on the market. On top of that, it can separate it from the acid-forming sulphides, so that we have the ability of pulling the tin into the first product and sending the rest to the EM sorter.”

Gavin Rech, Technical Manager at TOMRA

The two COM Tertiary XRT 1200 sorters went into operation in 2018. Initially, BMTJV’s strategy focused on low reject grades, devoting less focus to achieving the mass reject rate and overall process plant throughput. However, the specific conditions at the Renison mine affected the results achieved. The large variance in run of mine (ROM) particle size distribution resulted in insufficient stability in the feed to the circuit. In addition, the extremely wet conditions in west Tasmania and consequent high ambient moisture content, combined with the high moisture of the ore delivered from underground, further affected the sorting process.

In 2019, a new investigation was conducted into the ore sorting performance and led to a change of direction, where the operation shifted away from targeting low reject grades, towards sorting as aggressively as possible, according to Wraith, moving from a “tin recovery-based” operating strategy to a “mass reduction” one.

“We are getting 20-25% mass reduction, so 75-80% of the materials are going into the wet plant, and we are still achieving 97-98% tin recovery overall across the crushing circuit,” he said. “Pre-concentration didn’t materially impact overall recovery because the tin in the material that is rejected as waste is extremely fine grained and a proportion is associated with sulphides, so it wouldn’t have been fully recovered in the downstream wet plant and would have been lost to tailings.”

This approach, he said, is best for Bluestone’s application as it provides the ability to process 15-20% more tin units without having to upgrade the downstream concentrator.

Wraith added: “Operating the sorting circuit has slightly increased our overall processing cost, but this is more than offset by the large increase in ROM throughput by 15-20% and, thus, tin production, so the unit cost per tonne of tin produced is reduced by almost 10%. We’ve broken multiple production records in the last year in tin units, and this gives us confidence in what we can achieve because the machine performs over and over again if you treat it right and if you prepare your feed correctly.”

TOMRA XRT success leads to upgrade decision

In view of the results achieved with the two TOMRA XRT sorters, BMTJV decided to upgrade the ore sorting circuit with two new, recently launched XRT models with stainless steel internal parts and advanced features such as the TOMRA ACT user interface and the TOMRA Insight cloud-based platform, according to TOMRA.

“The decision to buy new machines was easy,” Wraith said. “The stainless steel will assist prolonging the TOMRA sorter’s life by protecting the unit from our high-moisture and corrosive environment. The more ergonomic design will help our maintenance teams, which is particularly important for machinery operating in these harsh conditions.”

Wraith said the use of TOMRA Insight, the ore sorting company’s subscription-based service that relays and analyses machine data, will “enhance everybody’s understanding and experience of the machines”.

He added: “It will be more of an analytical platform for our metallurgy and maintenance staff, providing ample opportunity to gain valuable information that can be analysed and optimised over time. The one feature I am personally interested in is the particle size monitoring through the machines, which will enhance our overall circuit performance because we have an integrated circuit with the crushing and screening plant. Feed preparation is key to maintain a consistent performance – knowing how well you’re preparing your feed in a live fashion can only end up with a better result.”

TOMRA will also be able to log into the machine and check the daily reports generated by TOMRA Insight, so its technical teams will be prepared ahead of site visits for maintenance or optimisation.

Wraith concluded: “TOMRA has been working with the site maintenance team to tailor solutions to our operating environment, which has been invaluable. TOMRA supported me through site visits, which included equipment inspections, site-based training of our personnel, and an openness to continually improving the technology and finetune it to our site-specific requirements. They assisted the site with troubleshooting, optimisation, discussing the nuts and bolts of the issues as they arose, and finding a solution that works.”

GR Engineering to build paste plant at Renison tin operations

GR Engineering Services Ltd says it has been awarded additional work by Bluestone Mines Tasmania Pty Ltd with a combined value of A$31.7 million ($23.6 million).

This work, to be performed by GR Engineering’s team in Queensland and Tasmania, Australia, includes an engineering, procurement and construction (EPC) contract involving the design, supply installation and commissioning of a new paste backfill plant and associated infrastructure at its Renison tin operations.

Early front-end engineering design work on the paste plant has been completed, GR Engineering said. The value of this project is A$23.9 million.

The Environment Protection Authority signed off on this paste plant build in August. It will redirect tailings from the existing tin process plant for dewatering and processing into filter cake, with the filter cake to then be stored and combined with cement in a batch process before being piped underground to stabilise mined out areas of the underground operations.

In addition, the company has been awarded an EPC contract for the HV Power Upgrade Project that includes the design, supply and installation of new transforms and HV switchgear for Bluestone’s existing main switchyard. The HV Upgrade Project has commenced, and the value of this work is A$7.8 million, the contractor said.

Geoff Jones, Managing Director, said: “GR Engineering has been pleased to support Bluestone Mines on multiple projects over the last two years and has developed a strong working relationship with management and the on-site team. We look forward to continuing our work with Bluestone Mines using GR Engineering’s team in Queensland and Tasmania.”

The Renison tin operations are owned 50:50 by Yunnan Tin Group and Metals X through the Bluestone Mines Tasmania Pty Ltd joint venture.

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.”

Alphamin bolsters gravity separation options with second Gekko IPJ

Alphamin Resources has purchased a second IPJ2400 for tin recovery at the Bisie tin project in the Democratic Republic of the Congo, Gekko Systems says.

The purchase of a second Gekko InLine Pressure Jig (IPJ) unit follows good performance from the first IPJ installed at this site in 2018 (pictured).

In addition, the Ririwai tin project has purchased an IPJ1500 in Nigeria.

The IPJ is a continuous gravity separation device that rapidly and efficiently pre-concentrates high-value and high-density mineral particles such as tin, tantalum, sulphides and free gold, Gekko says.

With installations worldwide, the unit has multiple applications including assisting in gangue rejection and combining with flotation to recover coarse minerals at the plus-100 micron range. The IPJ has significant benefits such as low water consumption, low footprint, ease of operation and 30 years of operational history.

SMS group assigned to FEED work at Cinovec lithium project

European Metals Holdings (EMH) has appointed SMS group Process Technologies as the lead engineer for minerals processing and lithium battery-grade chemicals production at the Cinovec project in the Czech Republic.

Cinovec, a joint venture between European Metals (49%) and ČEZ Group (51%, through its subsidiary Severočeské doly), is operated by Geomet. The project has recently received investment of around €29 million ($34 million) of funding from EIT InnoEnergy, the principal facilitator and organiser of the European Battery Alliance, for the project, seeing it through to a construction decision.

Under the agreement, SMS group, a leader in plant construction and mechanical engineering for the technology metals and materials sector, will provide a complete front-end engineering design (FEED) study as the major component of the ongoing definitive feasibility study (DFS) work at Cinovec.

Under the agreement, SMS will provide the following to the Cinovec project:

  • Full process integration from the point of delivery of ore to the underground crusher through to the delivery of finished battery-grade lithium chemicals for battery and cathode manufacturers;
  • The FEED will include all of the process steps – comminution, beneficiation, roasting, leaching and purification;
  • The FEED will encompass both the lithium process flowsheet and the tin/tungsten recovery circuit delivering metal concentrates to refineries; and
  • The FEED is intended to deliver a binding fixed price lump sum turnkey engineering procurement and construction (EPC) contract with associated process guarantee and product specification guarantees for battery-grade lithium chemicals. The combination of these will greatly assist to underwrite project financing from leading European and global financial institutions lending into this new energy electric vehicle-led industrial revolution, European Metals Holdings says.

The FEED study will commence immediately and SMS group is expected to deliver the EPC contract, as the final component part of the Cinovec DFS, by the end of 2021.

Herbert Weissenbaeck, Senior Vice President for Strategic Project Development at SMS group, said: “Having successfully completed thorough technical due diligence, we believe in the compelling value proposition of Geomet’s Cinovec lithium/tin/tungsten project, which is set to become a cornerstone of the e-mobility driven European battery metals landscape. SMS group is delighted to deploy its second-to-none technology metals and materials production know-how and EPC capabilities into this exciting project.”

EMH Executive Chairman, Keith Coughlan, added: “SMS is the ideal engineering partner for the Cinovec project as it is based in neighbouring Germany with a globally-respected process design capability. The appointment of SMS is the culmination of a negotiation and due diligence process that has lasted over a year.

“EMH, Geomet and ČEZ have all been consistently impressed by SMS group’s capabilities and insights into the development of efficient high recovery plants capable of producing very high quality end-products. Successful delivery of the FEED study will provide a gateway to financing institutions and offtakers of the highest quality. We believe that the intended product and process guarantees will greatly enhance the project finance either directly through commercial lenders or through the recently announced collaborative agreement with EIT InnoEnergy.”

A 2019 prefeasibility study on Cinovec outlined a 1.68 Mt/y operation producing 25,267 t of battery-grade lithium hydroxide over a mine life of 21 years. This came with a capital cost of $482.6 million.

Rafaella considers processing options after positive TOMRA XRT ore sorting tests

Sensor-based ore sorting test work from TOMRA Sorting Solutions has shown the potential for lowering the planned capital expenditure and operating costs associated with developing the Santa Comba tungsten-tin project in Galicia, Spain, project owner Rafaella Resources has reported.

The “exceptional” ore sorting results showed a 50% rejection of un-mineralised rock and an approximate doubling of feed grade, which would significantly lower the planned process capex and opex, and enhance process efficiency through a simpler process flowsheet, the company said. The 50% cut in process tonnage also reduces the project’s environmental impact, with a far lower volume of waste generated, lower energy consumption per unit of metal produced and reduced water consumption.

The “Grade Recovery Curve” showed the potential for over 90% tungsten recovery with an increased yield of up to 55% of feed mass, it added, while testing of the low-grade ores showed viable recovery from over 2 Mt of mineralisation not currently factored into the project’s economics.

The program tested two bulk samples selected from assayed drill core crushed to two size groups: +8 mm to -20mm and +20 mm to -40 mm. Sample No. 40 was circa-1,100 kg of average grade ore at 0.15% WO3, while Sample No. 41 was circa-250 kg of low-grade ore at 0.05% WO3.

TOMRA’s conclusion in its report was that “the results from this test work were positive for both sizes and samples. Significant upgrades of WO3, as well as high recoveries, were achieved in all test runs for sample ‘40’ using X-ray Transmission (XRT), while leaving rather low grades for WO3 in the waste fraction. A calculation has shown that a 90% recovery of tungsten can be possible at a waste removal of more than 50%.

“The low-grade sample ’41’ could be upgraded by a factor of 1.7 to 3. For further calculations, a waste grade between 0.025 and 0.030 is achievable.”

The success of the XRT sorting tests allows several mining and process options, Rafaella says, including:

  • Simplification of the process;
  • Bulk ore zone mining to reduce operational costs and maximise ore recovery;
  • In-pit sorting and conveying;
  • Bulk underground mining and sorting of wider ore zones using larger and longer stopes;
  • Separate sorting of sub-grade mineralisation; and
  • Sorting of satellite deposit ores prior to hauling to the process plant.

TOMRA estimates a throughput of 1 Mt/y of feed ore and circa-500,000 t/y of pre-concentrate would require two XRT units.

Rafaella’s Managing Director, Steven Turner, said the results from the ore sorting test work have exceeded the company’s expectations.

“The clear discrimination between ore-bearing rock and low grade or barren rock has delivered high recoveries and yields allowing for a simpler process plant,” he said. “The benefits of this simplification will be significant once the metallurgical studies are completed. These results are now being fed into the feasibility study that is in the final stages of completion.

“The company looks forward to providing the market with these exciting updates on the fast tracking of its flagship project over the coming weeks.”

Santa Comba is a brownfield project with a 5.1 Mt JORC 2012 compliant near-surface inferred resource at 0.203% WO3 and 0.014% Sn and an underground inferred resource of 234,000 t at 0.95% WO3 and 0.28% Sn.

Minespider wins EIT Raw Materials funding for supply chain transparency app

Minespider, a blockchain protocol for responsible mineral tracking, has been awarded a grant of over €180,000 ($213,732) from the EIT Raw Materials Booster Programme.

The program aims to support start-ups and SMEs in creating innovative products and services that will positively impact the raw materials sector, according to Minespider.

The grant will help Minespider develop OreSource, a due diligence product that helps mines and smelters capture key information that importers in the European Union need to comply with EU Conflict Mineral Regulation. The regulation, which comes into force in January 2021, requires EU importers of 3TG (tin, tungsten, tantalum and gold) to perform due diligence to determine whether their material comes from a conflict affected or high-risk area.

Minespider Founder and CEO, Nathan Williams, said: “European importers need to have better access to data to operate in this new regulatory environment. They require certain data to be included with the materials they purchase.”

The OreSource product extends the capabilities of Minespider’s open, public blockchain protocol, which allows companies to track their raw material shipments, demonstrating where the materials come from and the conditions under which they were produced, the company says. This blockchain creates digital certificates that separate data into three different layers, depending on whether the data should be publicly visible, transparent between members of the same supply chain, or private between a company and their customer.

“This allows their clients, including Volkswagen and Google, to share sensitive transparency information with their customers and other supply chain participants securely,” Minespider says.

The OreSource app allows mines and smelters to provide information to distinguish their products from the rest of the market. Mines and smelters who use the app upload key data such as bills of lading, invoices, company policies, and third-party certifications, which are assembled into a digital certificate and linked along the supply chain.

By affixing a QR code to a mineral shipment, or on an invoice, the recipients of the materials have all the data they need to ensure their compliance with the EU regulation, secured on Minespider’s public blockchain protocol, the company claims.

Williams continued: “Responsible producers are often at a disadvantage in the global market. OreSource is a solid first step toward making responsibly sourced material the norm instead of the exception.”

Companies importing material into Europe benefit from this information, as they have all they need to conduct due diligence. “This means they can view transport routes, analyse production site responsibility, and demonstrate a chain of custody for their raw materials,” Minespider says.

OreSource will also offer analytical tools that allow material importers to identify potential conflict areas and other red flags, the company says, enabling them to ask further questions when needed and ensure all of their imports have been sourced responsibly.

Williams concluded: “The EU and other government agencies are spearheading a new global era of sustainable sourcing. OreSource will support these efforts by ensuring that key data from mineral producers is captured in a transparent manner, and communicated along the supply chain. We are moving away from a world of anonymous commodities, to one of trusted products.”

Minespider looks to scale blockchain platform following fundraising

Minespider says it has raised a total of €2.8 million ($3.05 million) to continue developing its open blockchain protocol for supply chain tracking.

The money came from combined sources, including the EU Commission’s H2020’s SME Instrument Phase 2 program.

Minespider Founder and CEO, Nathan Williams, called the successful fundraising “an immense step forward” for the company and its “vision of a future where supply chains are transparent and sustainable”.

Minespider is an open blockchain protocol founded in 2018. As a team of 10, Minespider is based in Berlin, Germany, with operations in both Switzerland and Brazil. Its platform allows companies to create digital passports for their raw materials that keep track of where the materials come from and the conditions under which they were produced. The passports contain data that allows companies to verify that the materials they receive were produced in environmentally and socially sustainable ways, according to Minespider.

“Minespider passports separate data into three different layers, depending on whether the data should be publicly visible, visible to members of the same supply chain, or private between a company and their customer,” the company explained. “This allows companies to share sensitive transparency information with their customers and others further down the supply chain securely.”

Minespider makes this possible without a single trusted company running the system, using an advanced encryption system. This means that companies using Minespider retain total control over their own data.

Since its founding, Minespider has launched several traceability projects with industry players.

In 2018, Minespider partnered with Google to create a multi-stakeholder end-to-end mineral traceability consortium for the tin supply chain. The project formally commenced in 2019, with the addition of Cisco, SGS, Volkswagen, and Peru mining company Minsur (pictured at the San Rafael tin mine here), and has successfully tracked tin end-to-end and is now planning to incorporate new members.

In spring 2019, Minespider announced a joint project with Volkswagen to track its lead battery supply chain. This ongoing circular economy project involves two-thirds of the company’s global lead supply, according to the company. “Volkswagen intends this as a first step to employ blockchain technology for additional raw materials and supply chains,” the company said.

Williams added: “It has been an amazing experience to bring together so many industry leaders to work together on traceability. Now, with the backing of the European Commission and our investors we can scale the platform, bringing on many more participants who believe in the vision of transparent and responsible products.”

Part of funding came from the Horizon 2020 programme, where the European Commission selects potentially disruptive businesses to invest in and support as part of the SME Instrument. Minespider says it was chosen as a highly innovative SME and awarded ‘Very Good to Excellent (4.5 – 5)’ for all three key assessment criteria.

Williams said: “This funding shows how ready the EU Commission is to invest in these emerging and future technologies.”

TOMRA XRT leaves its mark on Minsur San Rafael tin mine

TOMRA Sorting Mining says Peru’s Minsur SA has felt the benefit of its X-ray Transmission (XRT) sensor-based ore sorting technology, with its San Rafael tin mine having seen an increase in reserves, plant capacity, overall recoveries and mine life since it was introduced.

Part of the Breca Group of companies, Minsur owns and operates the largest underground tin mining operation in the world, San Rafael. Located in the Eastern Mountain chain of the Andes in Peru at an altitude of 4,500-5,200 m above sea level, the mine contributed about 6% of the total world production of tin in 2015, with about 1 Mt of ore at an average grade of 2.13% mined and processed, resulting in 20,000 t of tin concentrate.

That same year, Minsur initiated a number of activities to ensure the future value of its asset, addressing challenges that included declining head grades and rising operating costs, according to TOMRA.

One of these activities involved an ore sorting project.

Started in 2015, in collaboration with TOMRA Sorting Mining, the project’s objective was to reject low-grade material in coarse particle size.

“By separating sub-economic material before entering the more cost-intensive wet processing, the project would address the bottleneck at the wet section and improve productivity by increasing the feed grade,” TOMRA explained. An added benefit expected from the project would be the longer life of the mine.

Three main factors indicated that sensor-based particle sorting for waste rejection would be effective at San Rafael:

  • The high absorption of transmitting X-rays of tin contained in cassiterite;
  • The structures of cassiterite, which are large enough to be detected by XRT technology; and
  • The significant degree of liberation of sub-economic waste on the particle level that may be subject to sensor-based particle sorting.

In order to assess the feasibility of the project, TOMRA conducted metallurgical tests on geological samples from San Rafael, followed by performance test work. The tests showed the deposit to be amenable to XRT ore sorting due to the presence of 70-80% of uneconomic particles that can be rejected over a wide size range, from 6 to 70 mm, TOMRA said.

The project was approved and, in view of the significant economic potential, was fast tracked and completed in just 14 months. TOMRA and its partner in Peru, which supplied and installed the XRT sorting system, worked closely with Minsur throughout the six-month ramp-up period.

The ore sorting project with TOMRA’s XRT system has delivered significant financial benefits from the beginning, with Minsur realising payback on its capital expenditure in just four months, according to TOMRA. In 2017, the ore sorting project contributed around 36% of Minsur’s total production with about 6,000 t of tin concentrate, the company said.

The project has reduced capital and operating costs at San Rafael in a number of ways:

  • Added value – TOMRA’s XRT sensor-based ore sorting is converting uneconomic waste material into economic ore, as material below the cutoff for the main plant can be treated with lower operating costs and converted into reserves;
  • Increased plant capacity – The main plant capacity has gone from 2,950 t/d before implementation to 3,200 t/d today, as a result of the crushing operation at the XRT sorting plant;
  • Significant improvement in the overall recovery in the main plant – from 90.5% to 92.5%. This is due to sensor-based ore sorting rejecting particles with very fine mineralised cassiterite that is too small for detection by the XRT system, resulting in higher grade and size of mineralisation;
  • Extended life-of-mine – today, about 24% of the feed to the sensor-based ore sorting plant come from low grade ore from underground, which in the past would have been below the cutoff. This increase in reserves significantly extends the life of mine;
  • Elimination of liabilities through the treatment and proper disposal of 100% of the stockpile; and
  • Decreased tailings disposal due to the sensor-based ore sorting system reducing the amount of waste by increasing the grade in the feed to the plant.

TOMRA concluded on the San Rafael case study: “The success of the project has demonstrated the high potential of TOMRA’s XRT technology, and as a result, the company plans to include XRT sensor-based ore sorting as a possible process route in all future projects.”