Tag Archives: Hatch

Rio Tinto verifies use of Pilbara ore for low-carbon iron-making using BioIron

Rio Tinto says it has proven the effectiveness of its low-carbon iron-making process using ores from its mines in Australia in a small-scale pilot plant in Germany, and is now planning the development of a larger-scale pilot plant to further assess its potential to help decarbonise the steel value chain.

The process, known as BioIron™, uses raw biomass instead of metallurgical coal as a reductant and microwave energy to convert Pilbara iron ore to metallic iron in the steelmaking process. BioIron has the potential to support near-zero CO2 steelmaking, and can result in net negative emissions if linked with carbon capture and storage, according to the company.

Over the past 18 months, the process has been tested extensively in Germany by a project team from Rio Tinto, Metso Outotec and the University of Nottingham’s Microwave Process Engineering Group. Development work was conducted in a small-scale pilot plant using batches of 1,000 golf ball-sized iron ore and biomass briquettes.

Rio Tinto Chief Commercial Officer, Alf Barrios, said: “Finding low-carbon solutions for iron and steelmaking is critical for the world as we tackle the challenges of climate change. Proving BioIron works at this scale is an exciting development given the implications it could have for global decarbonisation.

“The results from this initial testing phase show great promise and demonstrate that the BioIron process is well suited to Pilbara iron ore fines. BioIron is just one of the pathways we are developing in our decarbonisation work with our customers, universities and industry to reduce carbon emissions right across the steel value chain.”

BioIron’s potential was confirmed in a comprehensive and independent technical review by Hatch, the global engineering, project management and professional services firm, Rio said. Hatch noted the thorough work completed by the team and BioIron’s capacity to reduce greenhouse gas emissions while converting Pilbara iron ore into iron and steel.

The BioIron process will now be tested on a larger scale, at a specially designed continuous pilot plant with a capacity of 1 t/h. The design of the pilot plant is underway and Rio Tinto is considering suitable locations for its construction.

The BioIron process works using lignocellulosic biomass including agricultural by-products (eg wheat straw, canola stalks, barley straw, sugar cane bagasse) or purpose-grown crops. The biomass is blended with iron ore and heated by a combination of combusting gases released by the biomass and high-efficiency microwaves that can be powered by renewable energy.

Rio says it is aware of the complexities around the use of biomass supply and is working to ensure only sustainable sources of biomass are used. Accordingly, the company is undertaking a benchmarking study of biomass certification processes. Through discussions with environmental groups, as a first step Rio Tinto has ruled out sources that support the logging of old growth and High Conservation Value forests.

Hatch identifies opportunities to cut Australian tailings generation by as much as 30%

A new report from multi-disciplinary engineering, operational and development project, Hatch, estimates Australia’s mining waste can be reduced by 30% using already available technologies.

One of the biggest challenges currently facing the mining industry is managing the volume of tailings generated as minerals mining ramps up to meet the demands of the transition to renewable energy.

Undertaking an in-depth analysis to identify the technologies required to reduce or eliminate tailings of six key commodities (copper, gold, nickel, iron ore, coal and bauxite), Hatch investigated how tailings production would be impacted by applying the key technologies ‘themes’: advanced geometallurgy, ore sorting, advanced sensing and particle sorting, in-situ extraction, and preferential fracturing.

The company’s analysis revealed that technologies available today could reduce tailings by 20-30%, also identifying that, in the next 10-20 years, the integration of these technologies in future projects or expansions could provide an opportunity to reduce tailings by more than 50%.

Managing Director of Australia and Asia at Hatch, Jan Kwak (pictured), says the challenge of reducing tailings is a complex effort that is best solved utilising the innovative capacity of the entire mining supply chain.

“A balanced spread of researchers, METS (mining equipment, technology and services) companies, and operators in the mining industry are actively commercialising technologies,” he said. “Half (50%) of stakeholders identified are METS companies, whose core business is the supply of equipment and services of these technologies, indicating commercialisation is underway. This group was also present across the technologies that our analysis has shown to have higher TRLs (Technology Readiness Levels).”

The TRL ranking system measures the maturity of technologies, whereby Hatch graded technologies from zero (idea stage) to nine (commercial application).

For in-situ mining and preferential fracturing technology themes, there is a larger representation of research organisations and partnerships. This suggests collaboration is required to advance technological development, according to Hatch.

“It is vital that these stakeholders are highly engaged in the tailings reduction challenge in order to achieve the greatest cut through and introduce real change and advancement in the reduction of tailings, which will be needed to support the increase in mining activity while meeting emissions reduction targets,” added Kwak.

i-80 Gold brings Hatch in to evaluate Lone Tree autoclave restart

i-80 Gold Corp has awarded the engineering study for restart of the Lone Tree autoclave in Nevada, USA, to Hatch Ltd.

The study will complete a prefeasibility study (PFS) level mechanical and operational review of all aspects necessary for the restart of the company’s autoclave processing facility in northern Nevada.

i-80 acquired the Lone Tree property and associated infrastructure capable of, it says, processing all Nevada ore types from Nevada Gold Mines in 2021. The Lone Tree complex includes an autoclave, floatation circuit, tailings compound and heap leach facility that will become the hub of i-80’s Nevada operations and, it says, provide the platform to realise its future production growth plans of becoming a 500,000 oz/y producer.

The study, combined with an extensive metallurgical program of the mineralisation from the company’s Granite Creek, McCoy-Cove and Ruby Hill projects, will allow management to consider a range of restart opportunities and associated capital costs, it said. In the interim period, i-80 has secured processing agreements with Nevada Gold Mines so that it can commence underground development at Granite Creek, seeing material delivered to Nevada Gold Mines during the second half of 2022.

Matt Gili, President and Chief Operating Officer of i-80, said: “The extensive experience and expertise brought by Hatch Ltd will be one of the crucial elements enabling i-80’s success in re-commissioning and operating Nevada’s newest refractory processing facility.”

Gold industry ready to take action on cyanide use, DST’s Lemieux says

The move away from cyanide in gold processing has been talked of for many years, with words often not followed by actions, yet David Lemieux, President and CEO of Dundee Sustainable Technologies (DST), believes the industry is now starting to get serious about assessing alternative lixiviants.

His assertion comes on the back of one of the biggest gold miners in the world recently making such a move with the help of DST.

Back in December, Newmont signed a Technology Transfer Licensing Agreement with DST to use its cyanide-free gold extraction technology, known as the CLEVR Process™.

The CLEVR Process uses no cyanide, produces no toxic liquid or gaseous effluent and the solid residues are inert, stable and non-acid generating, according to the company. With fast leach kinetics of 1-2 hours, the ability to treat refractory ores and handle base metals, plus a competitive capital/operating expense, the solution has been gaining prominence in the gold market.

Having tested the process out on a variety of ores from various sources, DST is now in the commercialisation phase with CLEVR.

The pact with Newmont follows a successful test work program in the March quarter of this year, after which the gold miner expressed its interest in the execution of such an agreement. This led to Newmont conducting laboratory CLEVR leaching tests in its technical facilities in Englewood, Colorado.

As part of the agreement, DST and Newmont, agreed to:

  • A two-year, non-exclusive licence for the use of CLEVR at the laboratory scale in its Colorado technical facilities, with an option to renew for an additional two-year period under the same terms;
  • Technology implementation support by DST, including all technology laboratory protocols in addition to technical training sessions to initiate and support the technology transfer and practical operations;
  • Ongoing technology support, and for DST to review the laboratory test plans, execution and results conducted by Newmont; and
  • Any process scaling-up requirements resulting from positive applications of CLEVR will be conducted jointly with Newmont at DST’s technical facilities in Canada and/or on-site using DST’s technology and engineering group expertise.

Lemieux said the agreement should be viewed as an indication the gold industry is serious about assessing alternative processing approaches.

“DST’s CLEVR Process is a mature and developed novel gold processing technology that allows majors to properly assess how it can be implemented within a given project in terms of environmental benefits, operational efficiency, and operating and capital costs,” he told IM. “Such a level of detail then allows for properly integrated decision making.”

He said there had been increased interest over the years from the industry with regards to alternative processing approaches, which is likely to continue as more jurisdictions target cyanide operations and pressure operators to reduce their dependency on the lixiviant as the main and sole gold recovery mean.

CLEVR is one of two “novel metallurgical processes” DST has in its portfolio, the other being its GlassLock Process™.

GlassLock is a patented process for the sequestration and stabilisation of the arsenic often associated with copper, gold, silver or polymetallic deposits.

Dundee Sustainable Technologies GlassLock industrial demonstration plant on site at an operating copper smelter

In DST’s approach, the arsenic is incorporated into a highly stable and insoluble glass form that can contain up to 20% arsenic, while meeting or exceeding the requirements of the USA EPA’s toxicity characterisation leaching procedure and the Synthetic Precipitation Leaching Procedure, the company said.

Also in the commercialisation phase, GlassLock has been operating at an industrial scale thanks to a demonstration facility built and operated by DST.

According to Lemieux, the increased number of complex orebodies currently being developed means there is likely to be more interest in both CLEVR and GlassLock.

“The chemistry and conditions of the CLEVR process can allow for improved gold recoveries,” he said. “This, combined with DST’s ability to efficiently and permanently stabilise arsenic using GlassLock, is providing good opportunities for DST.”

The Glasslock process, he said, is equally targeting existing operations that have immediate arsenic production and stabilisation needs as well as operations/miners required to address and stabilise legacy arsenical material as part of their permitting requirements.

These abilities were recently recognised by engineering firm Hatch, which entered into a Technology Framework Agreement with DST that could see GlassLock used in combination with Hatch’s fluid bed reactor and arsenic dry scrubbing technologies on gold and arsenopyrite projects.

The objective of the agreement was to “synergise” Hatch’s extensive client base, commercialisation and marketing expertise, fluid bed reactor and arsenic dry scrubbing technologies, and large-scale equipment engineering, supply, procurement, and life cycle services capabilities with DST’s innovative technology to identify and develop potential gold and arsenopyrite projects using GlassLock, the companies said.

While they cannot point to specific results of these two technologies complementing each other, Lemieux said DST has continued and is currently working on testing programs where the roasting and vitrification approach is applied on complex gold concentrates.

“These programs were generated and originate from DST’s own development efforts, but we hope to see more similar opportunities coming from Hatch in the future,” he said.

Lemieux concluded: “Implementing novel metallurgical processes within the industry takes time and DST has progressed greatly, and continues to do so, on the design and operating parameters of specific on-site implementations of GlassLock and/or CLEVR facilities.”

Hatch engaged to take NexGen’s Rook I uranium project forward to FEED stage

NexGen Energy has awarded the engineering, procurement, and construction management (EPCM) contract for the front-end engineering design (FEED) stage of the Rook I uranium project in Saskatchewan, Canada, to Hatch, with work well underway.

Hatch, NexGen says, is a leader in project management and engineering and has extensive experience delivering mining projects in Saskatchewan and across Canada.

The awarding of the EPCM contract comes at the conclusion of a tender process involving multiple globally recognised industry firms, according to NexGen. Integrating fully into the owner’s team, Hatch is responsible for providing NexGen with engineering, procurement and execution planning services, along with supporting overall project management.

Following the completion of the Rook I feasibility study in February, NexGen is transitioning into the next stage of advanced project development with the commencement of the FEED stage. This feasibility study outlined a 1,300 t/d operation processing an average feed grade of 2.37% U3O8 and average uranium oxide production of 21.7 MIb/y over the life of mine of 10.7 years from the Arrow deposit.

In line with the optimised project execution strategy, the FEED stage will advance overall engineering to a 40-45% level of completion with associated cost estimate, fully define long-lead procurement actions, and further refine execution planning to prepare the project for the pending construction stage, NexGen said. This FEED stage is scheduled for completion in the September quarter of 2022 and will be undertaken concurrently with the engagement, Environmental Assessment and Licensing workstreams.

The 2021 site investigation program is advancing safely and is planned as a pre-cursor for FEED. Surface investigation field work is now complete, which consisted of test pits and sonic boreholes in locations of planned infrastructure. The collection of confirmational geological, geotechnical and hydrogeologic characterisation data is nearing completion, and early analysis of this data has validated the current designs established in the feasibility study and confirms the understanding of the rock mass proximal to the underground infrastructure and underground tailings management facility, according to NexGen.

Leigh Curyer, Chief Executive Officer, said: “Advancing into the FEED stage of development is another exciting milestone for the company, and we’re pleased to welcome Hatch to NexGen’s growing high performance team in advancing the Rook I project towards the start of construction. Hatch’s exemplary reputation in the global mining sector and deep understanding of value-driven project delivery aligns perfectly with NexGen’s commitment to elite standards and is a key step in the development of this leading global resource project. In parallel, the drafting of the project’s Environmental Impact Study and licensing workstreams nearing completion, together with regional exploration targeting new zones of potential ‘Arrow-type’ mineralisation, further exemplifies the NexGen team’s commitment to the successful execution of multiple workstreams.”

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

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

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

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

Key areas of work for Hatch on the DFS include:

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

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

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

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

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

CMIC-backed novel comminution technology hits commissioning milestone

The Canada Mining Innovation Council’s (CMIC) Conjugate Anvil Hammer Mill (CAHM) and MonoRoll platform technology project has reached a new milestone with hot commissioning of the MonoRoll at COREM’s testing facility in Quebec, Canada.

CAHM is a platform technology advancing two technologies in parallel where both designs break particles in a highly efficient thin particle bed. CAHM, according to CMIC, provides a more efficient alternative to high pressure grinding rolls and SAG mills, while the MonoRoll variant is designed for finer grinds and to replace inefficient rod and ball mills.

In a recent post, CMIC said hot commissioning of the MonoRoll at COREM’s testing facility, using some of the 300 t of ore contributed by Agnico Eagle Mines, was now complete. Although the MonoRoll is being tested using hard rock, there is also significant interest from the iron ore, cement and aggregate industries, CMIC says.

It added: “Fabrication of the CAHM machine is underway and if the optimised discrete element method modelling results hold, we are confident that the MonoRoll and the CAHM are on track to achieve the following significant benefits in ore grinding:

  • “Reduce energy consumption by an estimated 50% compared to best available technology;
  • “Eliminate grinding media;
  • “Increase ore feed reduction ratio; and
  • “Simplify the comminution circuits.”

CMIC is leading a consortium including experts in comminution, product development, engineering and testing as well as six major hard-rock mining companies guiding the effort and participating as potential first adopters. Included among the consortium is CTTI, Hatch, Glencore Canada – XPS (Expert Process Solutions), COREM, Teck, Agnico Eagle, Newmont and Kinross.

The MonoRoll technology is one of only six finalists in Impact Canada’s Crush It! Challenge. Launched in October 2018, Crush It! challenged Canadian innovators to deliver game-changing solutions for cleaner, more efficient rock processing.

CMIC said: “The MonoRoll project is the only finalist developing a novel grinding mill, and if the project wins the C$5 million ($3.9 million) Grand Prize, the funds would be used to engineer a large-scale machine to test in active mining operations.”

Hatch to commercialise CRC ORE’s Grade Engineering services

CRC ORE says it has taken an exciting step forward with Hatch, signing a deal that allows the multidisciplinary management, engineering and development consultancy to commercialise its Grade Engineering® Consulting Services.

Developed by the Brisbane-based Cooperative Research Centre for Optimising Resource Extraction (CRC ORE), Grade Engineering enables miners to reduce their energy, water and waste signatures while enhancing the productivity and profitability of their operations, according to CRC ORE.

It is an integrated approach to coarse rejection that matches a suite of separation technologies to ore specific characteristics and compares the net value of rejecting low value components in current feed streams with existing mine plans as part of a system-view.

Grade Engineering makes it possible to more efficiently treat lower grade ores and waste to extract valuable minerals, significantly increasing the life of mines and reducing their environmental footprint.

Achievable outcomes for mines, when deploying Grade Engineering at production scale, include significantly improved return on investment and lower capital intensity, according to CRC ORE.

BHP recently engaged CRC ORE and the Grade Engineering solution at its Olympic Dam mine, in South Australia, a location where the mine is actively examining bulk ore sensing and sorting opportunities.

“As Hatch adopts Grade Engineering and extends its reach into the mining industry, the value of such outcomes will increase for operations, clients and communities globally,” it added.

CRC ORE Chief Executive Officer, Dr Ben Adair (pictured signing the agreement on the left), said: “Hatch is a valued a long-term participant in CRC ORE and has actively championed Grade Engineering and its benefits to the industry. As a CRC ORE innovation, we are pleased that Grade Engineering will continue to be delivered by such a capable and engaged team.”

Dr Adair added: “At CRC ORE, our goal has been to develop our solutions to the highest possible standard and then ensure these are then managed by the most capable practitioners to take them to industry. Hatch is the perfect partner to ensure the long-term future of Grade Engineering.”

Under the terms of the commercialisation arrangement, Hatch will use Grade Engineering Intellectual Property for its consulting services.

Hatch Managing Director Australia and Asia, Jan Kwak (pictured signing the agreement on the right), said it was an honour to provide Grade Engineering consulting services.

“Being able to offer Grade Engineering as service is an exciting and positive step forward for Hatch and the mining industry,” Kwak said. “Grade Engineering enables miners to reduce their energy, water and waste signatures while enhancing the productivity and profitability of their operations.

“It also brings us a step closer to our vision for process intensification.”

The Grade Engineering team at Hatch will be headed by Dr Sevda Dehkhoda who has been working closely with CRC ORE since 2019.

“We look forward to continuing the legacy of CRC ORE by enabling the mining industry to intensify operational performance and minimise environmental footprint of the process by refining less waste,” Dr Dehkhoda said. “Adopting Grade Engineering into Hatch’s end-to-end value chain optimisation service offering strengthens Hatch’s position and its commitment to making positive change for mining operations and their communities.”

To facilitate the transition, CRC ORE’s Grade Engineering team will relocate to Hatch’s Brisbane office, supporting Hatch with current and potential users of Grade Engineering.

Latest Kamoa-Kakula copper studies reaffirm project’s world-class status

The latest economic studies on Ivanhoe Mines and Zijin Mining Group’s majority-owned Kamoa-Kakula project in the Democratic Republic of Congo have indicated the asset could become the world’s second largest copper mining complex.

First production at Kamoa-Kakula is less than a year away, but the project partners have continued with a series of economic studies that emphasise the world-class nature of the orebodies within their control.

The headline maker is the results of a preliminary economic assessment that has evaluated an integrated, multi-staged development to achieve a 19 Mt/y production rate at the mine, with peak annual copper production of more than 800,000 t.

At the same time, a prefeasibility study (PFS) has been carried out to look at mining 1.6 Mt/y from the Kansoko mine, in addition to 6 Mt/y already planned to be mined from Kakula, to fill a 7.6 Mt/y processing plant at Kakula.

A definitive feasibility study (DFS) has also evaluated the stage-one, 6 Mt/y plan at Kakula, which is currently being constructed and is less than a year away from producing first copper, according to Ivanhoe Co-Chair, Robert Friedland.

While the operation looks to have the scale of a world-class asset, it will also have top ranking ‘green’ credentials, according to Friedland.

“The Kakula mine has been designed to produce the world’s most environmentally-responsible copper, which is crucial for today’s new generation of environmentally- and socially-focused investors,” he said.

“Zijin shares our commitment to build the new mines at Kamoa-Kakula to industry-leading standards in terms of resource efficiency, water and energy usage, and minimising emissions. We are blessed with ultra-high copper grades in thick, shallow and flat-lying orebodies – allowing for large-scale, highly-productive, mechanised underground mining operations; and access to abundant clean, sustainable hydro electricity to power our mines – providing us with a distinct advantage in our goal to become the world’s ‘greenest’ copper miner and be among the world’s lowest greenhouse gas emitters per unit of copper produced.”

The project recently retained Hatch of Mississauga, Canada, to independently audit the greenhouse gas intensity metrics for the copper that will be produced at Kamoa-Kakula.

The Kamoa-Kakula Integrated Development Plan (IDP) 2020, as the companies refer to it, builds on the results of the previous studies announced in February 2019.

DFS to 6 Mt/y

The new DFS incorporates the advancement of development and construction activities to date, and has once again confirmed the outstanding economics of the first phase Kakula Mine, Ivanhoe said.

It evaluates the development of a stage one, 6 Mtpa underground mine and surface processing complex at the Kakula deposit with a capacity of 7.6 Mt/y, built in two modules of 3.8 Mt/y, with the first already under advanced construction (see photo). It comes with an internal rate of return of 77% and project payback period of 2.3 years.

The first module of 3.8 Mt/y commences production in the September quarter of 2021, and the second in the March quarter of 2023. The life-of-mine production scenario provides for 110 Mt to be mined at an average grade of 5.22% Cu, producing 8.5 Mt of high-grade copper concentrate.

The Kakula 2020 DFS mine access is via twin declines on the north side and a single decline on the south side of the deposit. One of the north declines will serve as the primary mine access, while the other decline is for the conveyor haulage system, which was recently commissioned.

The primary ore handling system will include a perimeter conveyor system connected to truck load-out points along the north side of the deposit. The perimeter conveyor system will terminate at the main conveyor decline.

The mining method for the Kakula deposit is primarily drift-and-fill using paste backfill (around 99%); with the exception of a room-and-pillar area close to the north declines, which will be mined in the early years of production. The paste backfill system will use a paste plant located on surface connected to a distribution system that includes a surface pipe network connected to bore holes located at each connection drive on the north side of the orebody, the company says.

The Kakula concentrator design incorporates a run-of-mine stockpile, followed by primary cone crushers operating in closed circuit with vibrating screens to produce 100% passing 50 mm material that is stockpiled.

At the end of August, the project’s pre-production surface ore stockpiles totalled an estimated 671,000 t grading 3.36% Cu, including 116,000 t of high-grade ore grading 6.08% Cu.

The crushed ore is fed to the high pressure grinding rolls operating in closed circuit with wet screening, at a product size of 80% (P80) passing 4.5 mm, which is gravity fed to the milling circuit.

The milling circuit incorporates two stages of ball milling in series in closed circuit with cyclone clusters for further size reduction and classification to a target grind size of 80% passing 53 micrometres (µm).

The milled slurry is pumped to the rougher and scavenger flotation circuit where the high-grade, or fast-floating rougher concentrate, and medium-grade, or slow-floating scavenger concentrate, are separated for further upgrading. The rougher concentrate is upgraded in the low entrainment high-grade cleaner stage to produce a high-grade concentrate.

The medium-grade or scavenger concentrate together with the tailings from the high-grade cleaner stage and the recycled scavenger recleaner tailings are combined and further upgraded in the scavenger cleaner circuit. The concentrate produced from the scavenger cleaner circuit, representing roughly 12% of the mill feed, is re-ground to a P80 of 10 µm prior to final cleaning in the low entrainment scavenger recleaner stage.

The scavenger recleaner concentrate is then combined with the high-grade cleaner concentrate to form final concentrate. The final concentrate is then thickened and pumped to the concentrate filter. Final filtered concentrate is then bagged for shipment to market.

The scavenger tailings and scavenger cleaner tailings are combined and thickened prior to being pumped to the backfill plant and/or to the tailings storage facility. Backfill will use approximately half of the tailings, with the remaining amount pumped to the tailings storage facility.

Based on extensive test work, the concentrator is expected to achieve an overall recovery of 85%, producing a very high-grade concentrate grading 57% copper. Kakula also benefits from having very low deleterious elements, including arsenic levels of 0.02%.

7.6 Mt/y PFS

The PFS evaluating mining 1.6 Mt/y from the Kansoko mine envisages an average annual production rate of 331,000 t of copper at a total cash cost of $1.23/lb copper for the first 10 years of operations, and annual copper production of up to 427,000 t by year four. This comes with an internal rate of return of 69% and project payback period of 2.5 years, according to Ivanhoe.

Development would see Kakula-Kansoko benefit from an ultra-high, average feed grade of 6.2% Cu over the first five years of operations, and 4.5% Cu on average over a 37-year mine life.

There are currently two mining crews at Kansoko, in addition to the 10 mining crews (three owner crews and seven contractor crews) currently at Kakula, with the ability to increase this number to fast-track the development of Kansoko, Ivanhoe said.

19 Mt/y option

The Kamoa-Kakula 2020 PEA presents initial production from Kakula at a rate of 6 Mt/y, followed by subsequent, separate underground mining operations at the nearby Kansoko, Kakula West and Kamoa North mines, along with the construction of a 1 Mt/y of concentrate direct-to-blister smelter. The smelter section of the study saw China Nerin Engineering act as the main engineering consultant with Outotec providing design and costing for propriety equipment.

The Kamoa North Area comprises five separate mines that will be developed as resources are mined out elsewhere to maintain the production rate at up to 19 Mt/y, with an overall life in excess of 40 years, Ivanhoe says.

For this integrated 19 Mt/y option, the PEA envisages $700 million in remaining initial capital costs, with future expansion at Kansoko, Kakula West and Kamoa North funded by cash flows from the Kakula mine, resulting in an internal rate of return of 56.2% and a payback period of 3.6 years.

This shows the potential for average annual production of 501,000 t of copper at a total cash cost of $1.07/lb copper during the first 10 years of operations and production of 805,000 t/y of copper by year eight, Ivanhoe said.

“At this future production rate, Kamoa-Kakula would rank as the world’s second largest copper mine,” the company said.

Alamos’ Island III goes on sinking mission for more gold

Having weighed five scenarios for a Phase III expansion at the Island gold mine, in Ontario, Canada, Alamos Gold is proceeding with a plan to carry out a blind sink down to the 1,373 m level, build a paste plant, and expand the mill and tailings facility at the operation to boost production.

The company is no stranger to shaft sinking; its Young-Davidson mine, also in Ontario, has just had its Northgate shaft commissioned after Cementation used large diameter raiseboring technology to establish it as part of an engineer, procure and construct contract.

Yet, the shaft sinking route was not a foregone conclusion, with three of the five scenarios involving ramp haulage.

The Phase III Expansion Study, carried out with assistance from Hatch, Cementation, Airfinders, Golder, Halyard, SRK and DRC Estimating, looked at these scenarios using Deswik planning software to find further growth at the mine.

Having added 900,000 oz of the yellow metal to its reserve base already this year and hit a rate of 1,240 t/d in the March quarter (ahead of the nameplate 1,200 t/d rate), the company was keen to leverage these ounces at the same time as come up with a sound economic proposition for expanding and extending the mine.

Of the five scenarios, three involved ramp haulage (two retaining the 1,200 t/d capacity and one at 1,600 t/d) and two would see a shaft installed (at 1,600 t/d or 2,000 t/d). All apart from one option included the addition of a paste plant.

The company settled on expanding throughput to 2,000 t/d, from 1,200 t/d, through a shaft and paste plant build, explaining that this option presented the best economics.

As a result, the Phase III expansion will involve an initial blind sink down to 1,373 m, that new paste plant, and an expansion of the mill and tailings facility.

These investments, which would see the mine life double to 16 years from the eight years currently outlined in the reserve base, are covered in the total capital of $1.07 billion, which the company says is offset by the lower sustaining capital and operating costs of this scenario versus all that were evaluated.

Following the completion of the shaft construction in 2025, it is envisaged the operation will transition from trucking ore and waste to skipping ore and waste to surface through the new shaft infrastructure.

Output would rise to 236,000 oz/y starting in 2025, 72% higher than the mid-point of previously issued guidance for the mine in 2020, while mine-site all-in sustaining costs would fall to $534/oz, a 30% drop on the 2020 guidance.

Combined, this made for an after-tax net present value (NPV) of $1.02 billion at a 5% discount rate, and an after-tax internal rate of return of 17%, using a base case gold price assumption of $1,450/oz.

“These are also the lowest costs of any scenario evaluated reflecting the significant productivity improvements, decreased ventilation requirements, increased automation, and higher throughput rates associated with the shaft,” the company said.

While the company did not spell out what automation elements would be included in this expansion, on a webcast discussing the results, Chris Bostwick, VP, Technical Services, included details of an LTE network underground installation at Island as one continuous improvement project for 2020.

An Alamos Gold spokesperson later confirmed to IM that the LTE network was in the process of being installed with the project expected to be completed by the end of this year. “The network is primarily being installed for voice communications and real-time data gathering,” the spokesperson said.

Asked whether it was a pre-cursor to the use of autonomous haulage at the operation ahead of the expansion, the spokesperson replied: “We don’t have any firm plans for increased automation of our mobile equipment currently, but are actively monitoring the progress with the technology and this remains a potential down the road.”

With regards to automation within the expanded mine scenario, the only aspect currently being considered is the automation or tele-remote operation of the rock breakers and skipping, the spokesperson confirmed.

“Some of the trucking requirements could be automated down the road as noted above,” the spokesperson said. “The shaft expansion will make the entire operation more automated and productive.”

John A McCluskey, President and Chief Executive Officer of Alamos Gold, reviewing the study, said Island Gold had proven to be a “tremendous acquisition” for Alamos.

“We acquired Island Gold in 2017 at a cost of approximately $600 million when it had 1.8 Moz of mineral reserves and resources,” he said. “This high-grade deposit has more than doubled to 3.7 Moz and we expect further growth yet.”

While the planned expansion would make Island more profitable through increased production and lower costs, it would also “best position the operation to benefit from additional exploration success”, he said.

Long-hole open stoping will continue to be utilised as the primary mining method at Island, however, increased development and key infrastructure changes including the addition of a paste plant and shaft will allow for mining rates to increase to 2,000 t/d, it said.

The addition of paste fill underground will allow for faster stope cycling, thereby supporting higher mining rates and providing increased geotechnical stability, according to Alamos. It will also increase mining recovery, resulting in an additional 100,000 oz of gold recovered over the life of mine (from existing pillars). This represented an in-situ value of $145 million at a gold price of $1,450/oz.

The paste plant will have a capacity of 2,000 t/d and capital cost of $34 million with the plant expected to be completed in the December quarter of 2023, Alamos said.

When it comes to the shaft options, which Alamos Gold evaluated with the help of Cementation, it was decided that a conventional blind sink methodology would be used to provide “improved schedule reliability with minimal impact on existing operations”.

A combined raisebore from the 840 m level, and blind sink option below the 840 m level was evaluated, however, this option would significantly impact existing operations, Alamos said. “The cuttings from the raisebore in the upper mine, and waste generated from the conventional sink in the lower mine, would displace underground throughput capacity and significantly reduce mining rates below 1,200 t/d by as much as 400 t/d over the next several years,” it said.

The settled-on option will see a 5 m diameter concrete-lined shaft constructed with a steel head frame. The shaft will house two 12 t skips in dedicated compartments for ore and waste movement and a double-deck service cage for the transport of personnel and materials.

The company estimated an overall shaft sinking rate of around 9.6 ft (2.9 m)/d, which included a ramp-up period.

While the shaft will be sunk to an initial depth of 1,373 m, the hoisting plant will be designed for an ultimate depth of 2,000 m providing flexibility to accommodate future exploration success, the company said.

At the initial depth of 1,373 m, the shaft has a capacity of 4,500 t/d, more than sufficient to accommodate the peak mining rates of 3,300 t/d (ore and waste), according to Alamos.

The underground ore and waste handling and loading pocket will be a conventional configuration like that of Young-Davidson, the company said.

Once skipped to surface, ore will be trucked to the expanded mill circuit.

On top of the payback being sweeter for the shaft expansion, ventilation requirements are also lower than under the ramp scenarios given the significantly smaller mobile fleet, Alamos said. This allows the shaft to serve as the only new required fresh air source.

The total construction capital for the shaft installation including all supporting infrastructure is anticipated to be $232 million.

Further, 56% of tailings will be placed underground reducing tailings dam raise requirements, a capital saving of $13 million, according to Alamos.

The mining rate ramp-up to 2,000 t/d after the shaft expansion will be supported by a total of five 42 t haul trucks. This compares with a peak of 18 haul trucks required to sustain ramp haulage at 1,200 t/d and 25 haul trucks for ramp haulage at 1,600 t/d, the company said.

“This contributes to the lower ventilation requirements with the shaft expansion, and significantly lower diesel usage and greenhouse gas emissions,” the company said.

The mill expansion will include upgrading the crushing circuit, adding a second parallel ball mill, and a new elution and carbon in pulp (CIP) circuit with carbon screens. The total cost of the mill expansion is expected to be around $40 million.

The flowsheet of the new circuit includes upgrades and expansions for the following major process operations:

  • New vibratory grizzly feeder;
  • New primary crusher;
  • New fine ore stockpile and conveyors;
  • Additional primary ball mill;
  • Primary ball mill screen for both ball mill circuits;
  • Existing thickener converted to high rate thickener;
  • Two additional leach tanks;
  • New elution plant and kiln (ADR); and
  • Tailing pumps.

Mill recoveries are expected to average 96.5% over the life of mine, consistent with the historical performance of the existing operation, it said.

To accommodate the increased electricity requirements with the larger mill and shaft, the power line to site will be upgraded at a cost of $14 million, it added.

Despite the backfill options with the envisaged paste plant, an expansion of the existing tailings impoundment area is underway and required under all scenarios to accommodate the growth in the deposit over the last several years, Alamos said.

“With two planned future raises beyond 2020 and the addition of the paste plant, the tailings facility has sufficient capacity to accommodate existing mineral reserves and resources,” it added.