Tag Archives: Tin

Zinnwald striving for battery-electric circularity with lithium project development

The development of the integrated Zinnwald lithium project in Germany could see the incorporation of a battery-electric fleet of LHDs and the return of metal production to a region of saxony with mining history dating back to the Middle Ages.

The London-listed owner of the project, Zinnwald Lithium Plc, has just released a preliminary economic study on its namesake project focused on supplying battery-grade lithium hydroxide to the European battery sector.

As with any responsible battery metal project being developed today, the project’s ‘green credentials’ are being considered even at this early stage.

Zinnwald Lithium has been keen to flag these, mentioning the project is located close to the German chemical industry, a fact that should enable it to draw on a well trained and experienced workforce with well-developed infrastructure, plus reduce the ‘carbon footprint’ of the final end-use product.

This focus will see all aspects of the project – from mining through to production of the end product – located near to the deposit itself.

Zinnwald Lithium also said the project has the potential to be a low- or ‘zero-waste’ project, as the vast majority of both its mined product and co-products have their own large-scale end-markets.

This could see it produce not only battery-grade lithium hydroxide monohydrate products, but sulphate of potash (SOP) for the fertiliser market and precipitated calcium carbonate (PCC) – the latter being a key filling material in the paper manufacturing process.

The project now includes an underground mine with a nominal output of approximately 880,000 t/y of ore at an estimated 3,004 ppm Li and 75,000 t/y of barren rock. Processing, including mechanical separation, lithium activation and lithium fabrication, will be carried out at an industrial facility near the village of Bärenstein, near the existing underground mine access and an existing site for tailings deposition with significant remaining capacity.

With a 7-km partly-existing network of underground drives and adits from the ‘Zinnerz Altenberg’ tin mine, which closed in 1991, already mapped out, the bulk of ore haulage is expected to be via either conveyor or rail

The nominal output capacity of the project is targeted at circa-12,000 t/y LiOH with circa-56,900 t/y of SOP, 16,000 t/y of PCC, circa-75,000 t/y of granite and 100,000 t/y of sand as by-products.

The company is looking to complete the ‘circularity’ dynamic in its fleet and equipment selection, according to CEO, Anton Du Plessis, who mentioned that electric LHDs could be used to load and haul ore to an ore pass in the envisaged operation.

He said the cost estimates to use such equipment – which are factored into the project’s $336.5 million initial construction capital expenditure bill – have come from Epiroc, which has a variety of battery-operated mobile equipment.

“The base case is battery-operated loaders,” he told IM. “The final selection will be based on an optimisation study where, in particular, partly trolley-fed haulage systems will be investigated.”

Forms of automation are also being studied, Du Plessis said, with the caveat that “only select technologies we consider proven” will be evaluated.

Zinnwald Lithium is also looking at electric options for long-hole drilling underground, with both battery-based units and cabled versions under consideration and requiring firming up in the optimisation study.

With a 7-km partly-existing network of underground drives and adits from the ‘Zinnerz Altenberg’ tin mine, which closed in 1991, already mapped out, the bulk of ore haulage is expected to be via either conveyor or rail. The former, of course, will be powered by electricity, but the company is also considering potential battery-electric options for the latter, according to Du Plessis.

The company is blessed with existing infrastructure at the mine, which should help it in advancing the project at the pace its potential end-use manufacturing suppliers would like. It is already evaluating options for the construction stage – with an engineering, procurement and construction management contract the most likely option – and it has plans to conclude a feasibility study by the end of next year.

Du Plessis said while most of the fixed assets have been removed or were deemed outdated a long time ago from the former operating underground mine, other infrastructure was in good shape.

“The excavations, main level, underground workshop, ventilation shafts and, particularly, 2020 refurbished access tunnel provide a very good starting point for our project,” he said. “The access tunnel was originally constructed for dewatering the old mine and, therefore, the mine and the tunnel have been maintained very well.”

The company is now shifting to the bankable feasibility study and currently selecting partners for the project.

With what it calls a “simple, five-stage processing” route confirmed by test work for the extracted material at Zinnwald, the company is looking to select OEMs with the optimal concept for the project, Du Plessis said.

“In the PEA, mineral processing equipment cost is based on Metso Outotec estimates, pyrometallurgy is based on Cemtec technology, and hydrometallurgy is based on various providers’ technology,” he clarified.

Orica’s WebGen wireless initiation system helps unlock reserves at BMTJV Renison tin mine

The Bluestone Mines Tasmania Joint venture (BMTJV) says it has become the first company in the Tasmania mining sector to demonstrate Orica’s fully wireless initiating system, WebGen™.

Since early 2021, BMTJV, the owner of the Renison tin mine, has been in consultation with Orica to implement the WebGen wireless blasting technology.

The first WebGen blast was successfully loaded in the Central Federal Basset (CFB_1458_5990_F4) section of the mine on June 13, 2022, with the first wireless blast in Tasmania successfully fired at BMTJV over the mine’s leaky feeder system on June 19.

Some 107 WebGen primers were loaded into BP4 (Block Panel 4) and “slept” for 14 days while BP3 was charged and fired, the company explained. Due to the geometry of the blast – and it being a high seismicity area – for B4 to be mined conventionally, a further 60 m of development would have been required to recover this ore.

The Orica WebGen system includes an i-kon™ plugin detonator, a Pentex™ W booster and a DRX™, which is a digital receiver comprising a multi-directional antenna and a battery that serves as the in-hole power source.

The Encoder Controller individually programs each wireless primer with its own unique encrypted codes. This encoder contributes to the inherent safety of the system, and programs each wireless primer with two codes, BMTJV explained. The first code is a unique group identity number for exclusive use at each mine and assigned to specified groups of primers which will sleep, wake and fire together. The second code is a ‘delay time’ specific to the wireless primer and blast design.

Mark Recklies, Chief Operating Officer – BMJTV, said: “WebGen has now been used to support continual safety improvements and deliver savings across the working mine.”

Tungsten West breaks ground at Hemerdon for TOMRA XRT ore sorters

Tungsten West says it has broken ground at its Hemerdon tungsten-tin mine in Devon, England, with the first sod turned for the installation of the TOMRA X-ray Transmission (XRT) sensor-based ore sorters.

This event, the company says, marks another major step in the company’s upgrade and refurbishment plans for the project’s processing plant.

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.

As announced earlier this month, the company took receipt of important long-lead equipment items, including the seven XRT ore sorters, which will make up part of the upgraded equipment the company plans to install into the front end of the processing plant. The XRT ore sorter will substantially improve and streamline operations once production restarts, minimising plant downtime, increasing recovery as well as a host of ESG benefits, it said.

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 units and one standby unit. 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.

Additionally, the company is pleased to announce the appointment of James McFarlane as Managing Director of Tungsten West. McFarlane previously held the position of Technical & Operations Director of the company.

Max Denning, Tungsten West CEO, said: “We are extremely excited to have broken ground at Hemerdon this week, marking an important milestone in the project’s restart. Ensuring the UK and the western hemisphere have got access to two key critical minerals has never been more profound. We are also delighted to announce James as our new Managing Director; his extensive experience will prove invaluable in the company’s development as we move closer to first production at Hemerdon.”

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.