Tag Archives: Arizona

South32 making engineering and design headway at Hermosa project

A stellar set of annual financial results has provided the ideal backdrop for South32 to update shareholders on its rapidly progressing Hermosa project in Arizona, USA.

Released late last month, the company’s 2022 financial year results showed off record earnings of $2.6 billion, record free cash flow from operations of $2.6 billion and record return on invested capital of 30.1%.

With group copper-equivalent production expected to increase by 14% in the next financial year, South32 looked to be well leveraged to in-demand metal markets at the right time.

The company has progressively been repositioning its portfolio toward metals critical for a low-carbon future, having already established a pipeline of high-quality development options. One of these high-quality development options is Hermosa.

Hermosa, which the company acquired outright back in 2018 as part of a takeover of Arizona Mining, is key to the company’s critical metals pursuit, having exposure to base and battery metals that are expected to grow in demand – both domestically in the US and internationally.

It is being designed as South32’s first ‘next generation mine’, according to Hermosa President, Pat Risner, with a series of technical reports highlighting its use of automation and technology to minimise its impact on the environment and target a carbon-neutral mining scenario in support of the group’s goal of achieving net zero operational greenhouse gas emissions by 2050.

These same reports also highlighted the potential to develop a sustainable, low-cost operation producing zinc, lead and silver from the Taylor deposit, with the bonus of possible battery-grade manganese output for rapidly growing domestic markets from the Clark deposit.

In the latest results, the company said it was devoting $290 million of growth capital expenditure in the 2023 financial year to progressing Hermosa as it invests in infrastructure to support critical path dewatering and progress study work for the Taylor Deposit. This is ahead of a planned final investment decision expected in mid-2023, which should coincide with the feasibility study.

South32 is devoting $290 million of growth capital expenditure in the 2023 financial year to progress Hermosa

Some $110 million of this was assigned to construction of a second water treatment plant (WTP2) to support orebody dewatering at the asset, alongside dewatering wells, piping systems and dewatering power infrastructure.

An additional $95 million was slated for engineering and initial construction ahead of shaft sinking at the operation, plus work to support power infrastructure and road construction.

The remaining amount was expected to support work across the broader Hermosa project, including Clark study costs and the Taylor feasibility study.

All signs from these results are that the company is laying the groundwork to develop this project ahead of that mid-2023 deadline.

In another sign of progress, South32 recently signed a “limited notice to proceed” for shaft engineering and design at Hermosa with contractor Redpath, Risner confirmed, adding that the award represented a positive step forward for the project.

“We look forward to continuing our engagement with local communities and all of our stakeholders as we make further progress with the project,” he said.

Redpath will no doubt be evaluating the technical studies that have been signed off to this point and informing future reports.

The PFS design for Taylor is a dual shaft mine which prioritises early access to higher grade mineralisation, supporting zinc-equivalent average grades of approximately 12% in the first five years of the mine plan. The proposed mining method, longhole open stoping, is similar to that used at Cannington, in Australia, and maximises productivity and enables a single stage ramp-up to the miner’s preferred development scenario of up to 4.3 Mt/y.

Yet, the Clark deposit opportunity – which has become even more tantalising with the US Government invoking the Defense Production Act and supporting the production of critical metals including manganese – could see the plan change.

The company says it may accelerate the prefeasibility study for the Clark deposit, which is spatially linked to the Taylor deposit. A scoping study has previously confirmed the potential for a separate, integrated underground mining operation producing battery-grade manganese, as well as zinc and silver from the deposit.

South32 previously said Clark has the potential to underpin a second development stage at Hermosa, with future studies to consider the opportunity to integrate its development with Taylor, potentially unlocking further operating and capital efficiencies.

With a PFS selection study expected later this year, investors and interested parties will soon know the role Clark could play in the wider Hermosa project.

What is easy to gauge already is that Hermosa is progressing on a track that many other development projects in in-demand sectors have gone down.

Rio Tinto signs pact to test Nuton copper heap-leach tech on Cactus primary sulphides

US-based copper developer and near-term producer, Arizona Sonoran Copper Company Inc, has entered into a one-year exclusivity period with Nuton™, a Rio Tinto Venture that, at its core, is a portfolio of proprietary copper leach related technologies and capability.

The exclusivity was triggered by successfully modelling the Cactus and Parks/Salyer ore samples and achieving the previously contemplated indicative metallurgical recoveries of at least 72% (copper recovery to cathode), which included chalcopyrite, under an investor rights agreement, Arizona Sonoran said.

Nuton will continue to test the application of its copper heap-leach related technology to the primary sulphide component of the Cactus Mine and Parks/Salyer Projects, in Arizona, through column leaching and scoping out capital and operating costs and design parameters, it added.

The sulphide potential is not included in the 2021 Cactus preliminary economic assessment, which contemplated a simple heap leach and SX-EW operation over an 18-year mine life, producing an average of 28,000 t/y of LME Grade A copper cathode.

Within the current Cactus project resource base is a primary sulphide mineral resource of 77.9 million short tons (70.7 Mt) at 0.35% CuT (indicated) and 111.2 million short tons at 0.35% CuT (inferred).

George Ogilvie, Arizona Sonoran President and CEO, said: “The Nuton preliminary work results indicate optionality for unlocking the substantial primary resource at Cactus, which is currently stranded at the bottom of the pit. Although we are in the early stages of testing chalcopyrite recoverability on an economic basis, we are encouraged by the initial results and the significant potential to continue building scale at Cactus and potentially at Parks/Salyer in the longer term.”

The preliminary metallurgical testing program covered ore sample selection, preparation and mineralogical characterisation to produce CFD modelling results providing early-stage indicative recoveries in respect of various ore types and specifically the chalcopyrite ore at Cactus. Further test work underway covers test column leaching and scoping out capital and operating costs and design parameters, the company said.

Nuton is an innovative new venture that aims to help grow Rio Tinto’s copper business. At its core is a portfolio of proprietary copper leach related technologies and capability – a product of almost 30 years of research and development. The Nuton technologies offer the potential to economically unlock known low-grade copper sulphide resources, copper bearing waste and tailings, and achieve higher copper recoveries on oxide and transitional material, allowing for a significantly increased copper production outcome, according to Rio. One of the key differentiators of Nuton is the potential to deliver leading environmental performance, including more efficient water usage, lower carbon emissions, and the ability to reclaim mine sites by reprocessing mine waste, it claims.

Hudbay’s Constancia continuous improvement quest leads to MineSense XRF trial

Hudbay Minerals has one of the lowest cost per tonne copper sulphide operations in Peru on its hands at Constancia, but it is intent on continuously improving the mine’s margins and environmental performance through a commitment to continuous improvement. This has recently led it to exploring the potential of sensor-based ore sorting.

Hudbay’s operations at Constancia include the Constancia and Pampacancha pits, an 86,000 t/d ore processing plant, a waste rock facility, a tailings management facility and other ancillary facilities that support the operations.

The company increased reserves at the mine, located in the Cusco department, by 33 Mt at a grade of 0.48% Cu and 0.115 g/t Au last year – an increase of approximately 11% in contained copper and 12% in contained gold over the prior year’s reserves.

With the incorporation of Pampacancha and Constancia North, annual production at Constancia is expected to average approximately 102,000 t of copper and 58,000 oz of gold from 2021 to 2028, an increase of 40% and 367%, respectively, from 2020 levels, which were partially impacted by an eight-week temporary mine interruption related to a government-declared state of emergency.

Constancia now has a 16-year mine life (to 2037) ahead of it, but the company thinks there is a lot more value it can leverage from this long-life asset and it has been looking at incorporating the latest technology to prove this.

In recent years it has, for instance, worked with Metso Outotec to improve rougher flotation performance at Constancia using Center Launders in four e300 TankCells and installed a private LTE network to digitise and modernise its open-pit operations.

Peter Amelunxen, Vice President of Technical Services at Hudbay, said the Constancia ore sorting project – which has seen Hudbay partner with MineSense on a plan to trial the Vancouver-based cleantech company’s ShovelSense X-ray Fluorescence (XRF)-based sorting technology – was one of many initiatives underway to further improve the operating efficiency at Constancia.

“The ore sorting program is separate from the recovery uplift program at Constancia,” Amelunxen said, referring to a “potentially high-return, low capital opportunity” that could boost milled copper recovery by 2-3%.

He added: “The ore sorting program is expected to yield positive results at the mining phase of the operation and is expected to increase the mill head grade and reduce metal loss to the waste rock storage facility.”

Back in April 2021 during a virtual site visit, Hudbay revealed it was trialling bulk sorting at Constancia as one of its “optimisation opportunities”, with Amelunxen updating IM in mid-January on progress.

Hudbay has previously evaluated particle sorting at its Snow Lake operations in Manitoba – with the benefits outlined in a desktop study “muted” given “bottlenecks and constraints”, Amelunxen said – but, at Constancia, it considered XRF sorting from the onset for copper-grade only pre-concentration, due to its perception that this application came with the lowest potential risk and highest probability of success.

The company has a three-phase evaluation process running to prove this, with phase one involving a “bulk sorting amenability study”, phase two moving up to laboratory-scale testing and phase three seeing trials in the field.

The “bulk sorting amenability study” looked at downhole grade heterogeneity to estimate curves of sortability versus unit volume, Amelunxen detailed. Laboratory testing of drill core samples to evaluate the sensor effectiveness was then carried out before an economic analysis and long-range-plan modelling was conducted.

With the concept and application of bulk sorting having cleared all these stage gates, Hudbay, in November, started pilot testing of XRF sensors on a loader. This involved fitting a ShovelSense unit onto the 19 cu.m bucket of a Cat 994H wheel loader, with around 20 small stockpiles of “known grades” loaded onto the bucket and dispatched into a feeder and sampling system (pictured below, credit: Engels Trejo, Manager Technical Services, Hudbay Peru). With this process completed, the company is now awaiting the results.

At a similar time, the company moved onto demonstration trials of a “production” ShovelSense sensor unit on the 27 cu.m bucket of a Hitachi ECX5600-6 shovel operating in one of the pits. It has collected the raw spectral data coming off this unit since the end of November, with plans to keep receiving and analysing sensor data through to next month.

“We should have the finalised XRF calibration in February, at which time we’ll process the raw data collected during the three-month trial period and compare it with the short-term mine plan (ie grades of ore shipped),” Amelunxen said. “So, by the end of February or early March, we’ll be able to validate or finetune the economic model.”

Should the results look favourable, Amelunxen is confident that leasing additional sensors and installing them on the other two Hitachi ECX5600-6 shovels will not take long.

Credit: Engels Trejo, Manager Technical Services, Hudbay Peru

“Plans may change somewhat as the program unfolds,” he said. “For example, we may have success sorting ore, but feel additional calibration is required for waste sorting at Pampacancha, in which case we may install production sensors on Constancia ores while doing another trial program at Pampacancha.

“It all depends on the precision of the XRF calibration.”

Higher head grades and potentially higher copper recoveries may be the headline benefits of using ore sorting technology, but Hudbay is equally focused on obtaining several key environmental benefits, including reduced consumption of energy and water.

On the latter, Amelunxen said: “This is expected due to the processing of less ‘waste’ by removing uneconomic material earlier in the process and reducing the hauling and processing costs of the uneconomic material.”

Looking even further forward – past a potential commercial implementation of XRF-based ore sorting at Constancia – the company plans to evaluate the application of other sensors, too.

“For our future development copper project in Arizona, we plan to look at other sensors as well,” Amelunxen said, referencing the company’s Rosemont asset.

This ore sorting project is not the only project the processing team at Constancia are examining, as Amelunxen already hinted at.

As part of the recovery uplift project, it is installing equipment that will allow the operation to increase the overall mass recovery of the roughers, which is currently constrained by the downstream pumps and cleaning circuit.

“This will allow us to achieve an expected 2-3% increase in copper recoveries without impacting concentrate grade,” Amelunxen said.

It has various initiatives underway under the “Moly plant improvement projects” banner, too. This includes flowsheet optimisation, pH control in the cleaners and pH reduction in the bulk cleaners.

“This project has been in the works since late 2019, and the new mechanical agitator installation in the cleaning cells was completed during the August 2021 schedule mill maintenance shutdown and the new nitrogen plant was commissioned in the second half of the year,” Amelunxen explained. “The next steps are pH control in the cleaners (with CO2), water balance optimisation and potentially installing a Jameson flotation cell as a pre-rougher (the cell is already on site and not in use, it will be repurposed pending results of the pH trials).”

A flotation reagent optimisation study is also on the cards, aimed at reducing zinc and lead contamination in the copper concentrate.

“A depressant addition system is on the way to site and should be installed in February, with plant trials commencing in March,” Amelunxen said, explaining that this followed laboratory test work completed in 2021.

Resolution Copper, Stantec leverage hydropanel tech to provide new clean water source for locals

Native American communities in eastern Arizona, USA, look set to benefit from a new source of clean drinking water through a project sponsored by Resolution Copper and Stantec to deploy innovative renewable “hydropanel” technology, the mine developer says.

Resolution Copper and Stantec are partnering with White Mountain Apache community members to provide 64 hydropanels on the Fort Apache Reservation and supporting hydropanel installation programs in other Native American communities.

White Mountain Apache Tribe District II Councilman, Jerold Altaha, said: “Water is valuable; it’s the life force of humanity. Thanks to this wonderful opportunity with Resolution Copper, our community of Carrizo will have access to safe, clean drinking water. Due to high levels of manganese in the main water wells, our community has had to depend on portable water tanks as a means to obtain drinking/cooking water for years. The hydropanels will now enable us to draw water from the air which will provide up to 10 litres of water or about 20 16 oz bottles a day, at no cost to the family. We are grateful for these opportunities which continue to make a difference in everyday life for our people and community.”

Stantec Water Business Operating Unit Leader, John Take, added: “We are proud to be a part of this effort to provide safe, reliable drinking water to the Native American communities in eastern Arizona. Innovative and renewable methods such as the hydropanel technology are playing an increased role in helping solve these complex problems in a sustainable manner.”

Hydropanels are a one-of-a-kind renewable water technology that uses the solar energy to provide a safe and consistent supply of drinking water by drawing pure, constantly replenished water vapour out of the sky, according to Resolution Copper. The self-contained system converts water molecules in the air into liquid water, which is collected and mineralised in a reservoir inside the panel, creating high-quality drinking water that can be delivered directly to homes, businesses, and community distribution centres.

Resolution Copper Project Director, Andrew Lye, said: “Water is a fundamental resource, and many members of our neighbouring Tribes do not have reliable access to safe drinking water. Projects like the hydropanel deployment will help alleviate some of the burden, and make a difference where it matters most. Resolution Copper continues to look for ways in which we can work in partnership to be part of the solution and support the communities around us.”

So far, Resolution Copper has invested nearly $2.8 million through partnerships and donations to projects with Native American Tribes and other communities in the Copper Corridor in 2021.

The Resolution Copper project is a proposed underground mine 96 km east of Phoenix, Arizona, near the town of Superior. The project is a joint venture owned by Rio Tinto (55%) and BHP (45%).

To date, more than $2 billion has been spent to develop and permit the project, including reclamation of the historic Magma Copper Mine site, sinking a second shaft to mining depth, rehabilitating an existing shaft and deepening to mining depth, extensive drilling and orebody testing, and the federal approval and public engagement process.

Taseko Mines starts commercial construction move at Florence ISR copper project

Taseko Mines, having just completed a $400 million bond refinancing and fundraising program, is moving forward with developing a commercial operation at its Florence in-situ recovery (ISR) copper project in Arizona, USA.

Capital requirements for the commercial production facility at Florence, which followed an ISR pilot project, are estimated at $230 million.

Pending final regulatory approvals and financing, Taseko has previously stated it could start construction of the commercial operation this year, with first production in late 2022.

Stuart McDonald, President of Taseko, said: “With the majority of the required funding for our Florence Copper project now in hand, we are moving forward with final design engineering of the commercial production facility as well as procurement of certain critical components.”

McDonald said the company is continuing to advance discussions with potential joint venture partners at Florence, but its strong cash balance and improved Gibraltar mine cash flows from copper prices currently over $3.70/Ib ($8,159/t) means it has “numerous options available” to obtain the remaining funding.

Russell Hallbauer, CEO of Taseko, added on Florence: “Florence is one of the least capital-intensive copper production facilities in the world and, when fully ramped up, will produce 40,000 t of high-quality cathode copper annually for the US domestic market.

“It is a green project, with carbon emissions and water and energy consumption all dramatically lower than a conventional mine, and, with C1 operating costs of $0.90/Ib of copper, it will also be in the lowest quartile of the global cost curve.”

Capstone considering Eriez HydroFloat tech to boost Pinto Valley performance

Capstone Mining is continuing to leverage innovative, low-cost technology at its Pinto Valley mine in an attempt to further utilise its existing solvent-extraction and electowinning (SX-EW) plant at the Arizona, USA, operation.

In the December quarter of 2019, Pinto Valley commenced a PV3 Optimization project designed to achieve safer, more reliable and higher capacity operations without major investments in new comminution equipment. A goal was set to achieve increased reliability, and higher throughput at maximised copper recovery with lower costs by leveraging new inexpensive technologies.

In its September quarter results, the company provided an update on this project, saying, to October 27, it had spent $17 million as part of its Phase 1 developments. This included crushing and mill equipment replacements, which are 60% complete with full completion expected by July 2021.

As part of its Phase 2 developments, Capstone spent $10 million in conveyor, mill auto controls, cyclone packs and tailings thickener upgrades. These upgrades are planned to be completed by the end of the September quarter of 2021.

On top of this, the miner completed a blast fragmentation optimisation project to target 30% fines (minus-0.5 in) in run of mine feed in the June quarter. In the same quarter, it completed a $300,000 tele-remote Cat D10 Dozer project to increase worker safety for high-risk applications. Another $6 million was spent on new mine equipment to increase efficiency while lowering diesel consumption, greenhouse gas emissions and other operating costs by $800,000/y. This project was completed in the September quarter.

In terms of its metallurgical innovation, the company continued to use novel catalytic technology developed by Jetti Resources at Pinto Valley, expected to deliver 300-350 MIb of copper cathode over the next 20 years from high-grade mine waste and historic stockpiles at all-in costs under $2/Ib. This technology uses a catalyst on primary sulphide minerals to disrupt the sulphur metal bond of the mineral and allow for a leaching solution to contact the copper. This enables the extraction of the metal to take place unimpeded.

Capstone also made plans to use new reagents to improve worker safety and improve overall metallurgical performance at its molybdenum plant re-start project. This would involve “minimal capital” and completion was targeted by the March quarter of 2021, it said.

Capstone says it is targeting to reach 60,000-63,000 t average daily throughput at Pinto Valley at an 85-90% recovery by 2022-2023. This is 17-30% higher than 2019 performance and is subject to further test work and studies to be completed in the first half of 2021, including tailings management, the company explained.

Added to this, following positive laboratory results on Pinto Valley flotation circuit samples, Capstone and Eriez are planning to commence pilot plant testing of the HydroFloat technology.

The HydroFloat fluidised bed assisted flotation cell has previously proven effective at floating coarse ore particles, up to two to three times the size limit of conventional flotation cells in commercial applications such as at Newcrest Mining’s Cadia Valley operation in Australia. Newcrest has recently decided to expand the use of this technology at the operation.

Capstone says the lab results at Pinto Valley had led Eriez to report an opportunity to reduce copper losses by up to 50%, thereby boosting overall recovery by up to 6% at Pinto Valley.

“Furthermore, the ability to recover coarse particles could allow for higher mill throughput while achieving high copper recovery,” Capstone said.

Other benefits could be lower grinding costs, lower water and energy consumption and increased tailings stability via coarser tailings.

Pilot testing is due to commence in November with results expected back in the March quarter of 2021.

Lastly, work on PV4 expansion scenarios to take advantage of around one billion tonnes of measured and indicated resources at 0.30% Cu continued during the September quarter.

“Given management’s confidence in PV3 Optimization progress to date, including the successful implementation of the novel catalytic technology from Jetti Resources to enhance leaching performance, Capstone has decided to evaluate expansion scenarios using existing assets rather than building new mill infrastructure,” the company said.

The study is assessing higher mining rates, higher cutoff grades to the mill, and an increased tonnage available for leaching.

While a significant mill expansion is not currently being contemplated, an expansion of Pinto Valley’s SX-EW capacity of 25 MIb/y may be necessary, it said. Extensive column leach test work will be conducted over 2021, with the overall PV4 expansion study expected to be released in 2022, Capstone added.

Taseko Mines eyes commercial production at Florence ISR copper project

Taseko Mines prospects of opening the US’ next commercial in-situ recovery (ISR) copper project have been strengthened following a recent hearing held by the Arizona Department of Environmental Quality (ADEQ).

At the public hearing, which came shortly after the ADEQ issued the company with a draft Aquifer Protection Permit (APP) for its commercial ISR project, Taseko’s plans for the development of the Florence copper project received “overwhelming support”, the company said.

The public hearing is a key part of the process for the granting of the full APP. It had participation from local community members, local business owners, elected state officials and city councillors, a state senator as well as representatives from the technical services sector, Taseko reported.

Russell Hallbauer, Chief Executive Officer and Director of Taseko, said: “30 interested parties spoke at the hearing, communicating great support for the company and the project, with only one individual not in favour. The ADEQ heard loud and clear that the community wants this project to advance to commercial operation.

“The company has worked very hard to inform the Florence community on not only the safeguards in place to ensure the environmental integrity of the project, but also the environmental benefits of the Florence copper extraction process. The extensive data collected from 18 months of operating the test facility is proof that the process works, both from a technical perspective as well as environmentally.”

The ADEQ will take written correspondence for another three weeks, until October 12, before writing and issuing the final permit, Taseko says.

Taseko commenced well field operations at its Florence ISR pilot project in central Arizona, US, in January 2019, reaching “commercial grade levels” less than six months after.

The commercial Florence mine is expected to have a copper production capacity of 85 MIb/y (38,555 t/y) and a 21-year mine life.

Lost Dutchman Mine ready to tell its metal separation tale

A company out of Arizona, USA, believes it has come up with a density separation technology that could upgrade heavy metal concentrates without the need for water or chemicals.

Lost Dutchman Mine (LDM), named after the legend of a rich Arizona gold deposit discovered by an elusive Dutch prospector, never since located, is the company in question. Being supported along the way by the Centre for Excellence in Mining Innovation (CEMI) out of Sudbury, Ontario, the firm is looking to find a way into the mining sector at a time when environmental, social and governance (ESG) concerns have reached a new high.

Mark Ogram, one of three Co-founders of LDM, explained the company’s aim and name, saying: “We’ve been able to find gold where people could not find it.

“We have now come up with a solution that requires no chemicals or water to purify a gold ore.”

While gold is the company’s initial focus, the process can be applied to most heavy metals including silver, copper and tungsten, according to Ogram. Some encouraging results have also been seen removing sulphides from gold ore ahead of further processing, in addition to ‘cleaning’ coal, he added.

A gravity separation process that uses air flow rather than water to separate these materials by density, the obvious comparisons are with Knelson concentrators or other separation technologies – all of which tend to use water or another medium for their processes. Ogram says Knelson concentrators are also for free gold, not refractory gold, the latter of which the LDM technology can cope with.

allmineral’s allair® technology also comes to mind as a comparison. This is a process that leverages many of the functions of the water-operated alljig® technology but, instead, uses air as the pulsating medium. So far, allair’s applications have been confined to mostly coal and other minerals.

Like many of these technologies, it is feed preparation that will prove decisive for the application of LDM technology, with ore crush size and moisture content the two key factors.

“We don’t think we would need ball mills to get the feed down to the right size,” LDM Co-founder Ken Abbott said. “A standard crushing and screening setup should be suitable.”

While test work to date has been with material in the 30-60 mesh range, Abbott is confident the technology will work with material from 100-200 mesh.

“It will be a little more of a sensitive process, but it does work should people require it,” he said.

When it comes to moisture content, a drying process will most likely be needed ahead of feeding to the LDM unit.

“The material needs to flow freely to work well,” Abbott said.

In-field test work involved the company using a tumble-type continuous screener/dryer to reach the appropriate moisture content, but a more ‘industrial’ process will be required in commercial applications.

The best results are likely to be achieved when both factors are consistent, according to LDM.

“The system requires a steady and uniform distribution in the feed cycle that includes surge capacity and automated material flow to ensure a steady feed rate,” the company says.

Dale A Shay, a consultant with RIMCON advising LDM, said vat leaching operations were already producing material at the appropriate size for the LDM technology to be tested. “They are also reducing the moisture content to an appropriate level,” he said.

Despite this, the company feels tailings applications may be the most suitable place to start with. This harks back to the ESG concerns miners are feeling – some of which revolves around tailings impoundment areas – as well as the fact the ‘conservative’ mining industry is generally more comfortable testing new technologies on material they already consider to be ‘waste’.

For the technology to prove out, the company will have to scale up its testing.

LDM has, to date, carried out benchtop, laboratory scale and in-field tests on low-grade material, but it has only reached a 1 ton (0.9 t) per hour rate.

“We would put in a tonne and get a few grams out,” Ogram said. “That is how we developed the technology.”

Despite there being a linear progression of recoveries from benchtop to lab to the field, LDM will need to go bigger to find the widescale applications it is after.

Yet, its potential entry into the market is well timed.

Removing the use of chemicals and water in a process that will most likely come after initial crushing could prove cost-effective, as well as environmentally sound.

Yes, the air flow component and feed drying will consume power on mine sites, but this ‘upfront’ operating cost will pay off further downstream as not as much material will be transported to make its way down the process flowsheet. It is more likely to go straight to tailings or backfill material feed.

Abbott explains: “The technology drastically reduces the material that will move onto final concentration, which substantially reduces material movement on site.”

For new developments, there is a knock-on benefit for permitting; the regulatory boxes are much more likely to be ticked when the words ‘water’ and ‘cyanide’ are absent from applications.

LDM Co-founder, Wayne Rod, sums this up: “Although from a cost perspective, it is expected to be competitive with other concentration technologies, the real savings will come on the ESG front and being able to reduce any environmental issues you may have.”

This is a message Rod and the rest of the LDM team are taking to the headquarters of major mining companies, where executives and board members are treating ESG challenges like a ‘cost’ they need to reduce to stay viable.

“As that ESG issue becomes even more prevalent, I see technology becoming a much bigger focus area,” Rod says. “Taking water and chemicals out of the concentration process will help alleviate some of that pressure.”

Heap leach operations edge closer at Bonanza Harquahala gold mine

5D Mining & Construction Inc is to build the heap leach pad for the Bonanza Harquahala mine, in Arizona, USA, after signing a contract with project owners Tombstone Exploration and Goldrock Resources.

Phase One construction of the Bonanza heap leach project is anticipated to start on or about May 25, with full project completion expected by mid-September, Tombstone Exploration and Goldrock Resources said.

The news comes just a month after the project, owned 40% by Tombstone and 60% by Goldrock, was signed off for construction by the Arizona Department of Environmental Quality.

The contract will see 5D supply labor, equipment and materials to perform all of the civil work and liner installation for phase one, the companies said.

“We are now moving into the construction phase of the leach pad with an estimated completion of the construction within 12 to 16 weeks,” Tombstone CEO and President, Alan Brown, said. “Once the construction is complete, we will start moving an estimated 500,000 t onto the leach pad and begin an estimated six- to eight-month processing period for all of the mined material in Phase One. Once leaching has started, bi-weekly delivery of the carbon to our designated gold processing facility is expected.”

Based on past metallurgical testing, production is budgeted at 23,000 oz of gold with potential for more, according to Brown.

Bonanza Manager, Todd Fayram, said he was “highly confident” in the company’s test results and expected first gold pour in mid- to late-September.

Phase Two, currently under consideration, includes a much bigger package where the owners have potentially identified 150,000-300,000 oz of gold in defined underground targets in and around the old Harquahala mine with significant upside potential, they said.

The 5D contract for construction for this first phase of the Bonanza Heap Leach Project includes all survey work required for layout and grading, debrushing the work area, demolishing obstructing concrete structures, relocating and stockpiling the existing tailings, mass grading for the pregnant leach solution pond and leach pad, all trenching and backfill for the liner anchor trench, fine grading for the liner, installation of the liner and perforated drain pipe, including required support work.

5D has provided work for some of the largest companies in the world, including BHP, Capstone Mining Corp, Freeport-McMoRan, Grupo Mexico and many others.

Brown said: “This construction agreement is another significant milestone for Tombstone. After careful deliberation, we are pleased to name 5D – a highly recognised construction company – as our partner to execute the first phase of the Bonanza heap leach project.”

Metso invests in Arizona repair facility after stellar 2019 results

Metso has made further investments in its Mesa repair facility in Arizona, USA, in order to, it says, optimise safety and broaden service capabilities.

The facility offers repairs and field services while supporting Metso’s Life Cycle Services contracts. It has seen steady growth since the opening in 2015, with 2019 setting a record for safety performance, revenue and profitability, according to the company.

One of the many upgrades to the facility includes the installation of “a state-of-the-art stress relief oven”. This investment was made to offer a more complete service to customers on large rebuilds, Metso said. “This will improve quality control as well as accelerate the turnaround times for our clients,” the company explained.

In addition to the stress relief oven, Mesa has also invested in other equipment to support the repair of mining screens, Wet Low Intensity Magnetic Separator (LIMS) drums, and babbitted bearings for mills.

A screen test stand has been manufactured and will be operational by the end of March, the company said. This will allow each screen rebuilt at Mesa to be test-run before being sent back out into the field, which will reduce the potential for issues during installation and start-up, according to the company.

Equipment needed to repair LIMS drums was also put in place last year and has seen a steady inflow of repairs coming from mines in the Iron Range of Minnesota, the company said.

Metso said: “In the future, the facility aims to further grow its portfolio of value-added services, to improve productivity and reduce operational costs for its clients in both the mining and aggregates sectors.”