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De Beers taking major technology steppingstone at Venetia Underground

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Making the transition from an open pit mine that has been operating successfully for 30 years to an underground operation that could become one of the most mechanised and automated in the world is not something that happens overnight.

De Beers Group embarked on the $2.3 billion underground expansion of its Venetia asset in Limpopo Province in 2012, in a move that represented the biggest single investment in South Africa’s diamond mining industry in decades.

Underground production began at the mine back in June this year, at a point when construction completion was estimated at 70%.

The introduction of autonomous mining systems performing multiple mining processes to deliver up to 6 Mt/y of kimberlite ore – for circa-4 Mct/y of diamonds – is now beginning, with a ramp-up process occurring over the next four years, according to Moses Madondo, Managing Director of De Beers Group Managed Operations.

“The technologies we are implementing – some of which are under development themselves – will be gradually phased in,” he told IM. “Where appropriate, we will take advantage of ‘proven’ technologies first to ease the change management process, before advancing to less mature technologies thereafter.

“The process should see us start operating areas of the mine in autonomous capacity by 2027.”

De Beers has engaged Sandvik Mining and Rock Solutions for its automated production machines, with the OEM delivering a 34-strong fleet made up of LHDs, ADTs, twin-boom drill rigs, roof bolters, cable bolters and production long hole drills. A further 12 units will be delivered in the future. These iSeries machines include 17- and 21-t payload LH517i and LH621i LHDs, 51-t payload TH551i ADTs, DD422i face drills, DS412i roof bolters, DS422i cable bolters and DL422i production drills.

Employee in the cab of one of the fleet of Sandvik machines

The underground mine will use sublevel caving to extract material from its K01 and K02 orebodies. Initially the ore will be hauled to surface using a combination of underground and surface haul trucks. As the operation matures, the hauling systems will transition to an automated truck loop in combination with vertical shafts for steady-state production.

Sandvik is also providing its AutoMine® system for the remote operation of loaders and trucks and its OptiMine® system for machine health monitoring, task management and location tracking.

Automation will be applied through a phased approach, beginning with manual operation and close monitoring of performance through data analytics. Automation will then gradually be introduced with the necessary training and experience in the operation and support of these technologies.

Madondo explained: “Our current fleet is made up of manually operated machines, which are optimised with automated task management. This process still requires an on-board operator, although many functions are automated.

“The next step would be autonomous machines, operated and overseen from surface, with our training centres already set up to deliver that.”

A pilot project to prepare the production team for the use of remote loading at the drawpoints and autonomous tramming to the tip is in the process of being established, with trials set for later this year and into 2024.

With sublevel cave mining, there is a risk of mud rushes and water ingress at drawpoints and remote loading will allow material to be loaded without putting operators at risk.

This pilot project will have a single loader operating under AutoMine Lite in a dedicated area on 46 Level that is isolated from other areas of the mine, with the machine controlled locally from a mobile tele-remote station just outside the autonomous operating area (ie not from surface).

An integrated operations centre on surface has been constructed and is in the final stages of commissioning.

Moses Madondo, Managing Director of De Beers Group Managed Operations

This is but a fraction of the emerging technology the company plans to employ at the mine, as Madondo highlighted.

“Of course, we will be integrating more technologies into the mix – digital mobility, data analytics, a cave management system, collision prevention, personnel alert systems, equipment location and tracking, production management through digital platforms, centralised blasting systems and digital twins,” he said. “All of these projects have people working on them to deliver our project objectives.”

For Madondo, the business case for employing such high levels of mechanisation and automation has only strengthened in the 11 years since the first shovel was placed in the ground for the underground project.

“This is a challenge with deep underground mining projects – they take a long time to develop and, in that period, technology and economics change,” he said. “It is, however, clear that mechanised mining allows you to take on these advanced technologies as the years go by.

“The investments are not just for technology’s sake. The business case must be built on our ability to improve safety and keep our people away from harm; as well as to make us more efficient and beat inflation, ensuring the margins we promised investors are realised.”

On the former, the company has partnered with Booyco Electronics on rolling out the South Africa-based company’s Level 9 – as defined by the Mining Industry Occupational Safety and Health (MOSH) organisation of South Africa – Booyco Electronics CWS850 collision prevention system at the mine.

“All of our Sandvik equipment is Level 9-enabled and we’re busy on this rollout,” Madondo said. “We’re already employing Level 7 (a system that warns pedestrians of their proximity to trackless mobile machinery) for this equipment. It’s now just a matter of getting to that new advanced level efficiently and safely.”

The company is also employing the Mobilaris Mining Intelligence platform for personnel location and situational awareness to help locate individuals in case of an emergency and notify them of incidents should they occur.

On the productivity side, the company is employing a cave management system to prevent overdrawing, Madondo says, linking the sub level caving mine plan with on-board LHD diagnostics and bucket weighing for efficiency and safety.

Process controller overseeing processing operations within the Venetia Mine

On top of OptiMine and AutoMine from Sandvik, the company is looking to integrate Howden’s Ventsim™ CONTROL system for monitoring, control and optimisation of underground mine ventilation in a ventilation on demand (VoD) application.

“We will gradually introduce VoD and Ventsim CONTROL as it allows us to 1) optimise the use of air and ventilation; and 2) retain the right condition and hygiene levels in the areas of the active mine,” Madondo said.

In an automated mining scenario, Ventsim CONTROL could potentially start ventilating an area of the mine in line with the expected arrival of the autonomous equipment, optimising the process and environment, and, as a result, reducing energy use.

Reaching the pinnacle

Also part of that discussion is decarbonisation – an area the company has already made significant progress on with its move underground.

“Transitioning from surface to underground has reset the energy balance,” Madondo said. “This has seen the site become far less reliant on energy from fossil fuel sources, with the big trucks and loaders from the pit replaced with smaller underground equipment and more electrical infrastructure.

“We predict by that, by 2030, 85% of all energy consumed will be electrical and only 6% will be diesel. That is a significant shift from the open-pit operation where nearly 85% of all energy consumed was from diesel.”

The company’s broader electrification work is currently in the review stage, but Madondo did provide some insight into the focus areas.

“We are looking at battery LHDs and trucks; we will consider trolley assist hauling loops and tethered electrical loading in some of the areas too,” he said. “It is all part of a progressive shift that will be integrated with the sourcing of renewable power for the mine.”

De Beers itself has set targets to become carbon neutral across its operations by 2030, Venetia Underground included.

The first electrification project the company is likely to embark on is a battery-electric retrofit of one of its light duty vehicles, Madondo said, explaining that this technology is relatively mature and comes with less infrastructure requirements due to the ability to charge the machines on surface.

“Our wider electrification plans are being influenced by the maturity of the technology; it may be more beneficial to wait until the adoption rate and learnings increase before we commit,” he added.

Even with the planned integration of such advanced technology at Venetia Underground, Madondo says De Beers still has some way to go to achieve the FutureSmart Mining innovation-led approach to sustainable mining that its parent company, Anglo American, advocates for.

“The pinnacle of De Beers mining expertise will probably be realised when we get to rollout our Diamond FutureSmart Mining, which ultimately is a mine design that we can use to develop future mines that make mining safer, more efficient, more sustainable and with a smaller environmental footprint,” he said.

“Of course, Venetia is certainly a steppingstone to that, but we will hopefully apply the learnings from Venetia for Jwaneng Underground (in Botswana) in the not-too-distant future. That could represent a different, more technologically advanced proposition where all processes are setup to benefit from the latest innovations.”

He concluded: “This will ensure we help create a healthy environment, that we catalyse thriving communities, and that we build trust as a corporate leader. We are shaping a future that creates shared value for all our stakeholders.”

ABB on extending mine production and asset life with ventilation on demand

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Ventilation on demand not only reduces energy usage and costs in underground mines, it can help extend production and the lifespan of existing infrastructure as part of a suite of electrification and automation solutions, say Marcos Hillal, Global Product Line Manager, Automation, ABB, and Jan Nyqvist, Global Product Manager, Automation Underground Mining, ABB.

By now, many readers will be familiar with ventilation on demand (VOD); what it is, what it does and the multiple benefits it offers mining companies in terms of efficiency, costs, safety and compliance.

Ventilation systems are the largest consumers of power in underground mines, accounting for 50% of energy use. VOD systems linked to the geolocation of people and vehicles intelligently adjust air flow to maximise air quality and minimise consumption. Supplying air into the mine (and expelling exhaust gases) only where and when it is needed can reduce overall energy usage by up to half. It also reduce cooling or heating needs of the circulated air.

Operators of subterranean mines must also comply with increasingly stringent safety regulations related to air quality, ensuring personnel are not exposed to excessive levels of CO, CO2, dust, humidity, toxic blasting and strata gases, and, chiefly, NO, nitrogen dioxide (NO2) emissions from diesel vehicles.

VOD not only supplies fresh air to underground mines, as well as removing spent or contaminated air, it automatically regulates air temperature to keep workers comfortable and safe, not to mention removing the need for them to enter potentially hazardous environments to manually operate fans.

Being smart about ventilation

So far, so good. However, what is not so well understood is how VOD can used to expand production and extend the life of ventilation infrastructure. With energy prices high and declining ore grades forcing operators into more remote, inhospitable locations in search of elusive reserves, technology solutions that can prolong the life of existing mine assets can offer an invaluable competitive edge.

So, how can VOD be applied to expand mine production? The answer is by delivering air even more smartly and efficiently based on actual operational parameters. ABB’s open platform, System 800xA, for example, utilises real-time data transmitted from sensors around the mine on key parameters such as the use of trucks, location of personnel, and gas, flow and temperature information.

ABB’s VOD solution, ABB Ability™ Ventilation Optimizer (VO), uses this data to operate the fans according to actual demands calculated from production schedules, as well as equipment status and location, reducing the amount of air that fans supply to certain sections of the mine by as much as 20-40%.

These savings can then be used to supply air to other sectors where they are needed more, whether that be new, hitherto unexplored places or existing areas where the operator wishes to maintain or increase production. What is more, VOD can do this by using existing infrastructure – ventilation shafts, for instance – which equates to significant savings on capex and manpower for customers.

Take automation to the next level

ABB Ability VO is designed to be integrated into each operation depending on that project’s specific characteristics and existing level of automation – how advanced the existing positioning system or communications backbone is, say – and comprises three separate levels.

Level one is the standard package whereby we connect ABB Ability VO to the ventilation equipment so that the customer can supervise and control the fans and air regulators remotely. They have the option to add further automation, meaning that the system can automatically adjust air flow based on the mine’s time and production schedule and, also, in the event of a fire or blasting in the mine.

In level two, positioning tools such as tracking on demand are integrated in the mine systems to pinpoint the exact location of vehicles, machines and people based on the production schedule, so the ventilation system throughout the mine can be automatically adjusted based on air flow levels.

Finally, level three is full automation or ‘closed loop’ ventilation. An algorithm computes the optimal operational set points on all the fans and regulators depending on demand and sensors continuously feedback data, allowing the system to optimise air flows and air quality, and minimise energy usage.

By introducing three implementation stages, VO system also gives customers time to adapt their processes and people so that the system can be fully integrated for maximum results.

A suite of scalable solutions

VO should not be viewed as an isolated solution, however; instead, it forms part of a portfolio of scalable, interconnected digital and automation technologies that together give operators complete control of a multitude of functions, from dewatering the mine to material tracking.

Future innovations include online monitoring to ensure the ventilation system is working in the most optimal way. In terms of scalability, since VO is based on our market leader 800xA platform, other advanced solutions can be integrated, such as ABB’s asset management and power monitoring systems, so mines can benefit from the company’s full range of ABB’s dedicated solutions for underground mine operations, all under one single integrated platform.

In this way, VOD forms part of a package of digital, automation and electrification technologies that, when deployed together, can transform underground mines into safer, more efficient environments.

Howden strives for further ventilation on demand optimisation

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Earlier this year, Howden’s Lead Software Engineer, Benoit Dussault, told IM that the company was starting to delve into machine learning as part of the evolution of Ventsim CONTROL, and he recently provided a few more details about the impact this could have on its flagship ventilation optimisation system.

The company’s aim for this project – as with all ongoing ventilation projects – is to optimise the flow of air and the other varying parameters that come with adequately ventilating underground mines.

Ventsim CONTROL has proven in the past to improve the ventilation process, with its highest level solution – level 5 – offering a ventilation on demand (VoD) solution bolstered by “optimisation algorithms”.

Dussault said the company is looking to bolster these algorithms with machine learning to help predict and detect certain parameters that influence the way mine ventilation systems work.

“With that, we could detect something that a sensor alone cannot do and analyse data to see things we could not see before,” he explained.

For instance, with Howden’s recently added temperature controllers for Ventsim CONTROL – both for cooling and heating purposes – the system could leverage machine-learning algorithms to predict how long it would take to reach a specific temperature sub point at an area of a mine, optimising the heat and airflow so that the set point is reached at the scheduled time.

This type of process reduces not only the energy consumption associated with ventilation but also the emissions associated with powering the processes.

“There is already optimisation happening with Ventsim CONTROL on a regular basis, but, with the assistance of machine learning and predictive modelling, we can optimise this further,” Dussault said.

As both software developers, engineers and mining practice leads, Howden, a Chart Industries Company, is well positioned to make the most of the industry’s machine-learning advances, according to Dussault.

“In the mining industry, there are a lot of PLC programmers and automation specialists, but very few of these are software developers,” he said. “I think we have much unique expertise to allow us to lead this adoption.”

To facilitate this move, Howden is moving Ventsim CONTROL over to a web-based user interface with BI Dashboards and reporting, making it easier to understand what the data is saying about potential ventilation optimisation advances.

Howden is currently evaluating the customer needs to build a machine-learning prototype that will be tested extensively in-house ahead of deployment at a mine site.

Feeding the algorithm with the right kind of data will be paramount to the project’s success, according to Dussault.

“No matter what you try to do with machine learning, if your data is wrong, your model will be wrong,” he said.

Eldorado testing LTE-backed Newtrax ventilation on demand solution at Olympias

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Eldorado Gold has confirmed it is testing Newtrax’s environmental monitoring platform and ventilation on demand (VoD) solution at the Olympias mine in Greece.

Mine ventilation represents the single largest electrical load at the Olympias mine and, in response to the EU energy crisis and Eldorado’s own Energy and Carbon Management System, the company has been aggressively advancing VoD implementation at the Greek operation.

The benefits associated with VoD include:

  • Targeted air circulation and improved air quality as the working environment is upgraded as fresh air is distributed through the mine in a manner that ensures workers’ health and safety;
  • Right-sizing fans to provide the required volumetric flow rates (from a static to a dynamic and intelligent air supply leading to a reduction of the total required airflow within a mine);
  • Improving energy efficiency and power consumption – by reducing the total airflow, energy can be saved in disproportionately high amounts due to the cubic relationship between volume flow and fan power; and
  • Enabling the production and development activities at the lower levels of the mine.

To obtain the immediate benefits of VoD, the Olympias mine operations team implemented a manual solution during 2022, where the team adjusts ventilation fan operations each day based on the daily mine plan. As part of this, variable speed drives were applied to many of the fans to allow air flow adjustments to meet operational needs with minimum electricity consumption. This process is being carried out via the control room on surface, with a SCADA system used to disconnect fans that are not planned to be used during the day.

This transition saw ventilation fan consumption decrease from about 620 kWh/mth of electricity consumption per kW of installed fan capacity to about 377 kWh/mth of electricity consumption per kW of fan capacity, representing a 40% decrease in energy consumption, according to Simon Hille, SVP, Technical Services and Operations. At the end of 2022, the mine had 3.1 MW of installed ventilation capacity.

“This 40% reduction represents about 9,051 MWh/y of electricity savings and about 3,800 t/y of GHG emission reductions (utilising the updated emissions factor of 0.42 t CO2e/MWh),” he told IM.

While manual VoD has been very effective, automated VoD will further decrease energy consumption and eliminate the many worker hours required to implement VoD on a daily basis, according to Hille.

This is where the company brought in Newtrax, part of Sandvik Mining and Rock Solutions, to implement an automated VoD system.

The Olympias mine will be the first Newtrax installation utilising LTE as the communications medium versus low frequency radio (leaky feeder) utilised previously, according to Eldorado. LTE was installed in August 2022 with the help of Cosmote.

The automated platform will also leverage data from the existing Micromine fleet management system and RFID-based employee location tags provided by Newtrax. Ventilation will then be provided by surface fans with higher ventilation capacities.

Olympias already uses Accutron Technology to monitor air flow velocity and Trolex technology to monitor mine air quality, according to Hille.

In addition to the VoD benefits, the Newtrax technology will improve mine safety (mine evacuation and rescue) as well as improve productivity by allowing mine supervision to have a better understanding of resource locations for improved decision making, the company says.

“Technology and connectivity are the key parameters for VoD to operate effectively,” Hille said. “Automated employee and equipment geo-location is necessary as it helps adjust ventilation delivery to different areas by effectively shutting down entire areas and thus reducing the overall ventilation demands. This requires smooth connectivity with the LTE across the mine site.”

Last month, Newtrax installed five Bluetooth low energy (BLE) devices on select mobile machinery to test system connectivity. Once troubleshooting is complete and communication is established between the underground fans and Newtrax BLE devices, full-sized implementation will be considered with equipment procurement, installation and commissioning to be done by end of Q1 (March quarter) 2024.

On top of this, Eldorado Gold is evaluating non-diesel powered equipment for all new equipment purchases and, in some cases, as an alternative to equipment rebuilds.

“The mine ventilation benefits of equipment electrification are included in the evaluation of that equipment,” Hille said.

Howden continues to bring energy and ventilation efficiency to mining operations

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Howden’s Ventsim™ CONTROL may have been introduced 15 years ago in Canada, but the cutting-edge mining innovation continues to be refined, the company says.

Ventsim is designed to reduce energy consumption, associated costs and improve energy efficiency in underground mine ventilation systems.

The Ventsim software suite uses advanced algorithms to analyse real-time data and adjust ventilation equipment to maximise energy savings while maintaining safe working conditions. As the global mining industry continues to face increased pressure to reduce its carbon footprint, it offers a valuable solution by optimising energy usage and reducing wasted energy, Howden says.

Howden, a Chart Industries Company, has focused on innovation with this software to meet the needs of ventilation and automation engineers by developing a solution that requires no prior programming. The site team can manage Ventsim CONTROL on an ongoing basis which means there is no need to continually bring in third parties to make changes as the mine’s requirements change.

This was a need in the market in 2009 when Ventsim software was introduced. The software has become even more relevant today, where resources are expensive and scarce, and mine plans – in many cases – need to be commodity price sensitive. Ventsim CONTROL can incorporate sensors, hardware, and software from any third-party supplier and has grown to become a key ventilation-engineering tool across the mining sector.

In recent years, Howden has developed the software with the complementary addition of 3D modelling and simulation components of Ventsim DESIGN, a mine ventilation simulation software, to allow mining companies to achieve optimal visualisation of their ventilation systems across their operations.

In a recent update, the software’s 3D tracking visualisation of personnel and vehicles was improved through the ability to tap into existing site-wide tracking systems at most modern underground mines.

Benoit Dussault, Lead Software Engineer at Howden, told IM: “We are working hand-in-hand with tracking providers on this solution, incorporating the x, y, z coordinates associated with these ‘tags’ or deploying a zone-based approach where these coordinates are not available.”

A real-time gas simulation that can incorporate data inputs from gas sensors around the mine and predict the gas concentrations going into areas not equipped with sensors is also being integrated into the software platform as part of expanded control and optimisation functionality. The same can be said about heat simulation, which was introduced last year.

The company is also refining its energy management and control toolkit, building on the energy dashboards it has had in place to visualise energy consumption, energy savings and, more recently, carbon emissions.

“We are implementing a carbon calculator this year that builds on those energy reports,” Dussault explained. “The software will track your emissions, allowing companies to benchmark their consumption and emissions against a plan.”

Later in 2023 and into 2024, the company hopes to put ventilation-focused, artificial intelligence-backed algorithms to work at mine sites, potentially taking the company’s ventilation optimisation abilities to new heights.

This would also coincide with a new web-based interface, introducing BI dashboards and reporting to an already impressive line-up of features.

While all these elements have global applications – and Howden itself is a global player in the ventilation sector – Dussault was keen to emphasise Canada’s influence on the ongoing evolution of Ventsim CONTROL: “Our first full Ventilation on Demand installation projects were in Canada back in 2009 and 2012. The latter, the Newmont Eleonore mine, is still significant for us from a project perspective. They [the mines in Canada] continue to play a vital role in developing the software continuously.”

Sustainable mining solutions to meet net-zero targets

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Mining is an essential process that has become even more critical as the world moves towards a greater energy transition. Minerals are a crucial component in clean energy technologies such as electric vehicles, solar panels and batteries, and the demand for these minerals is increasing, Howden’s Livio Salvestro says.*

According to the International Energy Agency, the demand for certain minerals to support the transition is projected to increase more than twentyfold by 2040. Meeting global carbon reduction targets is essential to mitigating the effects of climate change and the mining industry will play a key role in this effort. Mining practices must adapt and evolve to be more environmentally friendly and help decarbonise operations. In line with global efforts to meet the Paris Agreement objective, mining companies are setting targets to reduce their greenhouse gas (GHG) emissions.

A PwC survey of CEOs in 2021 showed 76% of global mining and metals executives were concerned about climate change and environmental damage, up from 57% a year earlier. And 70% of global mining executives said they planned to increase their long-term investments in sustainability and environmental, social and governance (ESG) initiatives.

Challenges in decarbonising the industry

There are several ways mines can reduce their carbon footprint, but moving to a 100% electric mine would represent a transformational shift for underground mine operations where diesel engines have dominated for over 100 years. Underground diesel equipment represents one of the biggest environmental challenges a mine faces. Switching to an electric energy source can significantly impact mines, reducing their ventilation shaft and tunnel sizes; the size of their fans and heating and cooling systems; their carbon footprint; and their capital investment.

Diesel equipment can also represent a significant financial burden within a mine’s ventilation cost footprint, so moving to electric sources while updating ventilation solutions can be highly effective for improving overall environmental credentials. While progress has been made, which will result in future benefits, there are opportunities for the mining industry to reduce energy consumption and emissions through a combination of advanced sustainable technologies, actionable insight into mine operations and automation – solutions that exist today.

Energy efficiency in mining

Digital advancements are enabling the industry to become more efficient, safe and productive by collecting, analysing and implementing data to optimise mine conditions, processes and maintenance decisions. Digital technologies and automation can also be applied to ventilation.

Ventilation is a vital process in a mine’s operation. It is necessary for providing fresher air and, in some instances, cooling the working environment, clearing blast fumes and diluting exhaust fumes and gases generated by mining.

This means it needs to run consistently and reliably, often accounting for substantial operating costs and up to 40-50% of a mine’s total energy consumption. Advanced technology and more efficient ventilation systems can reduce costs and significantly contribute to a mine’s carbon reduction objectives.

Livio Salvestro is Global Mining Team Leader at Howden

The primary goals of ongoing mine ventilation developments are to mitigate environmental impact, as already outlined, by reducing GHG emissions and improving underground air quality. They are also necessary to create efficiency that is sustainable and reliable, so a mine continues to produce energy savings throughout its lifecycle. Optimising overall health and safety models is crucial, which rely on automation for unprecedented operational capabilities.

There are several solutions to support these goals, including electric mine air heating, which provides a simple and safe solution with zero emissions. Through a modular design approach, these systems use industrial grade, Incoloy tubular elements selected for optimal functionality and maintenance.

Optimised ventilation systems are also available to drive energy savings and contribute to net zero commitments. Products like Ventsim™ CONTROL utilise intelligent software that communicates with hardware devices to remotely monitor, control and automate airflow and heating and cooling systems.

Thermal heat recovery can result in operational flexibility and reduced emissions. By employing a system of heat transfer coils, liquid pumping stations and control and automation technology, the mine can generate heat recovery using potential sources like waste heat from mine exhaust air, central boilers, power generators, and compressors or green sources such as geothermal energy.

Ammonia refrigeration systems offer a sustainable solution with no harmful CO2 or HFC emissions. Ammonia is considered the “green refrigerant” and has been used for many years, however, it is now coming into its own with the demands for reducing the footprint of hydrocarbon and HCFC refrigerants that can affect the atmosphere.

Demonstrable ventilation success

Companies like Howden have been successfully supplying these green mine ventilation solutions for years, and the results are clear.

The Oyu Tolgoi mine in Mongolia required a new indirect air heating, ventilation and filtration solution. Howden developed a unique thermal heat recovery solution that included airlock access, pipe work engineering, main and bypass damper, and fan outlet. Howden’s solution can be used as a reference for the remainder of the mine’s development. Each heater house was designed to capture 22 MW of waste heat from the hot water system.

An electric heating system was supplied to a high-grade underground mine in northern British Columbia, Canada. The system included two direct-fired, hybrid M.I.D mine air heaters and enabled the mine’s electric mine air heating system to take advantage of low electricity prices.

Ventilation automation has been a part of several large-scale mine operations for decades and some mines have experienced reductions of more than 50-60% in energy consumption and 11,500 t of CO2 emissions.

The Newmont Éléonore mine in Quebec, Canada, brought in a Ventsim CONTROL system, which included ventilation monitoring stations and the automation of all ventilation equipment. To date, there has been a 43% reduction in mine heating costs, a 56% drop in underground ventilation electricity costs and a 73% decrease in the cost of surface ventilation electricity.

Recognising the proven benefits of Howden’s Ventilation on Demand system, Newmont – Éléonore won the Eureka Prize from Écotech Québec.

As a pioneer, Howden engineered ammonia refrigeration systems in mines during the 1970s. More recently, the company supplied ammonia screw chillers at the Prominent Hill mine in South Australia for OZ Minerals. In partnership with the customer, Howden created solutions that had the highest functionality while supporting their net-zero targets.

As environmental pressure builds, especially on mining companies, now is the time to implement proven solutions to support a cleaner energy future.

*Livio Salvestro is Global Mining Team Leader at Howden

Howden, Agnico Eagle Fosterville to complete Oz mining first with Ventsim CONTROL VoD installation

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Howden says it has secured a contract for the upgrade of an existent licence of its Ventsim™ CONTROL ventilation system at the Agnico Eagle-owned Fosterville Gold Mine in Victoria, Australia.

The initial installation of Ventsim CONTROL Level 3 (scheduling and flow control) has already greatly improved the operability and flexibility of the ventilation system, as well as providing efficiency to pay for itself in just six months, Howden claims. Now, in a first for the Australian mining sector, the mine tracking system will be integrated to Ventsim CONTROL Level 4. This will provide real-time feedback on the vehicle locations in Ventsim CONTROL to adjust the ventilation automatically based on demand.

Camille Levy, President of the Asia Pacific Region at Howden, said: “This next stage contract for Fosterville mine is significant for Australian mining and the Howden Ventsim team as it represents the first Ventsim CONTROL Level 4 system that has been commissioned remotely as well as a first in APAC. The success of the operation and the level of power it saves serve as a test case for further installations of Ventsim CONTROL globally. The fact that the system paid for itself within six months is impressive.

“As the system allows the mine to optimise its ventilation based on fully remote vehicle and personnel monitoring, it directly contributes to Australia’s 2030 emissions reduction targets – something of which the Howden team is very proud.”

Level 4 – Ventilation on Demand (VoD) is the process of adjusting mine air flow in real time based on vehicle and personnel position. Ventsim CONTROL provides an ‘on demand’ solution for mine ventilation. Software connected to hardware devices remotely monitors, controls and automates airflow. The technology provides safer ventilation that is more productive and cost effective, according to the company. The Ventsim CONTROL solution also offers a 3D modelling capability within the software, which helps users to better predict and control air flows based on what is evidenced in the simulation.

Howden recently announced its target to be carbon net zero by 2035 through the purchase of renewable energy and carbon-free energy; efficiency gains from energy conservation measures; and by renewable energy projects at its manufacturing facilities. The largest impact the business will have on global sustainability will be through its partnership with customers to supply equipment that will make a major impact on their carbon emissions and sustainability, it says.

In 2020, Fosterville produced a record 640,467 oz of gold at an average grade of 33.9 g/t Au and average recoveries of 98.9%.

Howden tapping into South African deep mining experience

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Mines are getting deeper with every year that passes – 30 m deeper, if industry reports are correct.

With increased depth, comes increased ventilation and cooling needs, a fact Howden knows well from its experience of working with the deepest mines in South Africa.

Originally founded in 1854 by James Howden in Scotland as a marine engineering firm, Howden made an entry into South Africa in the 1950s seeking to cater to the demands of the mining and power industries. By the 1960s, it was helping equip the country’s deep gold mines with all the ventilation and cooling products they needed to extract ore safely and productively from kilometres below surface.

“Initially mines used only ventilation as a method of cooling, but, as mining depth increased, mechanical refrigeration was required to counteract the increasing heat loads in mines,” Theuns Wasserman: Team Leader – Howden SA’s Mine Cooling and Compressor Division, told IM.

This saw many deep gold mines in South Africa install Freon™ centrifugal chillers above and below ground to provide the necessary cooling for personnel and machines underground.

While an improvement on the status quo, the heat rejection system for underground machines proved problematic, with the machines’ cooling capacity limited by the temperature and amount of reject air available, according to Wasserman. At the same time, the water quality of the mines resulted in high fouling on the piping shell and tube heat exchangers employed on these early centrifugal chillers.

This resulted in the machines being limited to cooled water temperatures of 6-8°C, he said.

To rectify this, mines started to pump chilled air from surface to underground. While this boosted cooling capacity, the required infrastructure took up space in the shaft and the process was both energy- and opex-intensive.

Battling these issues, mines looked to maximise the amount of cooled air that was sent underground via chilled water plants.

This led Howden to introduce ammonia-based screw chillers into South African mines, which were initially employed in series after the existing surface centrifugal chillers. This enabled a step change in the amount of cooling that could be transported to these deep underground gold mines, bringing the average water temperature sent from surface down from 6-8°C, to 1°C. Mines were able to use the same shaft pipe infrastructure, which many of them had in place, while drastically increasing the amount of cooling sent to deep levels.

Some 20 years after their introduction, Howden, as a leading market player in the space, developed the WRV 510 – a large block screw compressor with a 510 mm rotor. This was, at the time, one of the largest screw compressors on the market, which suited the module sizes of the chillers required for refrigerating these deep South African mines.

“That changed the game as mines could install a single refrigeration machine with 10-12 MW of capacity, instead of a fleet of chillers,” Wasserman said. “At the same time, ammonia, as a ‘green’ refrigerant, perfectly suited the screw compressor and plate heat exchanger combination.”

The considerations around the use of ammonia were formalised into mining-specific ammonia codes and safety standards that Howden was instrumental in devising. These have since been updated and incorporated into South African legislation.

Such success is evidenced by more than 350 MW of ammonia-based refrigeration capacity installed in the South African mining sector, believed to be the most of any country in the world.

But Howden’s South Africa-based innovations did not end there, with the company, in 1985, adding ice production plants on surface to its expanding mine cooling remit.

With surface and underground refrigeration options maximised or deemed too expensive, mines needed a new cooling solution to further expand mining into even deeper levels.

The first surface ice plant (example below) was installed by Howden in 1985 at the ERPM (East Rand Proprietary Mines) mine, east of Johannesburg, which had a final total cooling capacity of some 40 MW with an ice production capacity of 4,320 t/h.

The basis of operation saw ice produced on surface and sent down the mine shaft to an underground ice dam, with water from the ice dam then circulated to underground cooling stations or used as service water for drilling. The ice melt was then pumped back to surface.

The primary benefit of this ice system was the pumping cost reduction, being some 75-80% less than the opex associated with a system where chilled water is sent from surface. This is down to the inherent “cooling energy stored in the phase change of the water”, Wasserman said, explaining that 1 kg/s of ice has the same cooling capacity as 4.5-5 kg/s of chilled water.

With a “superior positional efficiency”, an underground water dam can be maintained at 2-5°C to enhance the thermal performance of underground air cooling stations – again, maximising the cooling capacity.

Another benefit of ice production plants that has specific relevance in South Africa – a country renowned for grid instability – is the ability for the system to be used as a method of thermal storage where ice is produced and accumulated in the underground ice dam and used during peak periods.

This latter advantage led to the development of an Eskom-backed industry collaboration project involving Howden looking at using an ice plant to reduce peak power demand, with test cases situated at Mponeng, the world’s deepest underground mine, and Moab Khotsong.

“We froze up a dam of water during the night (off-peak) and that water and ice melt was used during peak time as a mine cooling source,” Wasserman explained. “The baseload refrigeration plant was switched off during peak periods, taking the pressure off the grid.”

It led to the development of a full turnkey ice plant at Mponeng where Howden carried out works including the civils, electrical and mechanical equipment for a 12 MW, 120 t/h ice plant.

The latest addition to the primary cooling strategy for Mponeng mine that already included soft ice, chilled water from surface, surface bulk air coolers (BACs) and underground refrigeration systems, the ice plant was equipped with duplex stainless steel plate ice makers to deal with the high concentrations of dissolved salts and chlorides present in the mine water at the operation.

It is this wealth of experience in South Africa and a focus on solutions rather than solely products that continues to be translated on a global scale, as MG Mynhardt, Howden’s current Manager of Compressors in South Africa and soon-to-be Head of Global Mine Cooling, said.

With more mines going deeper and space within the shaft at a premium, it is easy to see such a solution having applications in other parts of the world, as Wasserman hinted at.

Mynhardt said: “Howden has been ‘exporting’ its South African deep mine cooling expertise for decades. Back in the 1990s, for instance, we provided a mine cooling solution for an underground gold mine in Nevada.

“One interesting technology utilised by some South African mines is thermal ice storage that is used for load shifting – where thermal energy is stored in large ice dams. The ice is produced during peak periods and utilised in peak periods,” he said. “Conventionally, refrigeration plants are sized for maximum ambient temperature, which might be experienced for three hours a day in the summer months. Yet, if you have a facility to store your cooling energy, you could reduce this capacity.”

The parallels with battery energy storage for replacing excess spinning reserves are obvious here.

“If you have an electricity tariff plan where you have a quite high peak power tariff that you want to shift to a cheaper off-peak tariff, these ice plant solutions could make for a strong business case,” he said. “The upfront capital for the plant could be offset against the lower operating costs.”

At the same time as these, BACs used at mines in South Africa for decades are gaining prominence across the globe.

The newest generation BACs have higher thermal efficiency than their predecessors, lower limits on the shaft air temperature and a reduced footprint when compared with traditional BAC construction types. They are also embedded with the cooling on demand (CoD) module within Howden’s Ventsim CONTROL platform where the temperature of the shaft collar air can be automatically modified to meet the demand below surface.

Howden supplied three of these new-generation BACs in the past year to customers in Brazil and Burkina Faso.

The company can also manufacture customised solutions to deal with challenging operating environments; a recent example being the “unique BAC” operating with ammonia chillers installed at the Carrapateena mine in South Australia for OZ Minerals.

“Without any water available, in Australia, Howden installed dry condensers with Howden ammonia-based compressors along with a closed-loop dry bulk air cooler,” Wasserman said of this installation. “These coolers were engineered for ultimate efficiency considering it was a ‘dry’ plant as opposed to an open-headed spray cooler installed in applications where water resources are available.”

And the company is currently trialling an “uptime” condition monitoring solution at the 8 MW surface BAC plant (pictured below) it designed and engineered for Fortuna Silver’s Yaramoko mine (previously Roxgold) in Burkina Faso.

This system, monitored from Howden’s Johannesburg facility, allows the company to advise of potential efficiency gains and maintenance issues to ensure the plant is run as optimally as possible. The BAC installation at Ero Copper’s Caraiba mining complex in Brazil has also been designed to use such functionality.

This isn’t to say Howden is only focused on projects outside of South Africa – far from it.

Its Total Mine Ventilation Solution (TMVS) platform is continuing to build sustainable, value-adding relationships, which saw the company carry out two ventilation on demand (VoD) feasibility studies in the country in 2021.

Just over the border in Zimbabwe, it is working on a project that could see VoD-enablement of an automated door at an underground mine, to allow it to open at different increments and supply the required quantity of cooled air based on specific vehicle demand.

Such technology developments – using existing available mine infrastructure and readily available data feeds – will become part and parcel of the Howden offering in the future.

Howden’s South Africa experience – learning how to engineer cooling solutions to deal with the poor water quality at its deep gold mines, how to make solutions as energy efficient as possible to circumvent grid issues and how to cater to some of the strictest air quality, temperature and occupational hygiene regulations across the globe – will continue to pay off for mines all over the world.

Yamana Gold retains electrification path for Wasamac in new study

Automation, Comminution of minerals, Environmental, Mine ventilation, Mineral processing, Mineral project development, Mining equipment, Power supply for mines, Precious metals, Sustainable mining, Water management, , , , , , , , , , , , , ,

Yamana Gold has reiterated a plan to minimise the amount of carbon emissions generated with the development and operation of the Wasamac gold project in Quebec, Canada, in its first study since acquiring the asset from Monarch Gold.

Monarch, prior to being taken over by Yamana Gold, had laid out plans for an underground mine at Wasamac producing 6,000 t/d, on average, with an expected mine life of 11 years. It expected to use a Rail-Veyor® electrically powered, remote-controlled underground haulage system in addition to an almost entirely electric fleet of production and development equipment.

The December 2018 feasibility study by BBA indicated the Wasamac deposit hosted a measured and indicated mineral resource of 29.86 Mt at an average grade of 2.7 g/t Au, for a total of 2.6 Moz of gold, and proven and probable mineral reserves of 21.46 Mt at an average grade of 2.56 g/t Au, for a total of 1.8 Moz of gold. The study forecast average annual production of 142,000 oz of gold for 11 years at a cash cost of $550/oz.

With drilling, due diligence and further studies, Yamana Gold, in studies forming the new feasibility level studies, has come up with baseline technical and financial aspects of the Wasamac project that, it says, underpin the decision to advance the project to production.

This has resulted in a few changes to the Wasamac plan.

For starters, the company plans to use the extract the now 1.91 Moz of reserves quicker than Monarch’s strategy, with a rapid production ramp-up in the first year followed by sustained gold production of approximately 200,000 oz/y for at least the next four years.

Including the ramp-up phase, average annual production for the first five years of operation is expected to be 184,000 oz, the company said, with life of mine production of 169,000 oz/y. Mill throughput has been increased to 7,000 t/d, on average, but the plant and associated infrastructure were being sized for 7,500 t/d. Production could start up in the December quarter of 2026, the initial capital expense was expected to be $416 million and all-in sustaining costs over the life of mine had been calculated at $828/oz.

The use of a conveyor is still within this plan, but a company spokesperson told IM that Yamana was now considering a conventional belt conveyor rather than the Rail-Veyor system.

Yamana explained: “The optimised materials handling system uses ore passes and haul trucks to transport ore from the production levels to a central underground primary crusher. The haul trucks will be automated to allow haulage to continue between shifts. From the underground crusher, ore will be transported to the crushed-ore stockpile on the surface using a 3-km-long conventional conveyor system in two segments.”

Yamana added: “Using a conveyor rather than diesel trucks to transport ore to surface reduces CO2 emissions by 2,233 t/y, equivalent to taking 500 cars off the road. Over the life of mine, the company expects to reduce CO2 emissions by more than 20,000 t.”

The aim to use electric vehicles wherever possible remains in place.

“The Wasamac underground mine is designed to create a safe working environment and reduce consumption of non-renewable energy through the use of electric and high-efficiency equipment,” the company said. “Yamana has selected electric and battery-electric mobile equipment provided that the equipment is available at the required specifications.

“Battery-electric underground haul trucks are not yet available at the required capacity with autonomous operation, so diesel trucks have been selected in combination with the underground conveyor. However, Yamana continues to collaborate with equipment suppliers with the expectation that the desired battery-electric equipment will be available before Wasamac is in operation.”

In tandem with this, the company plans to use a ventilation on demand solution and high-efficiency fans to reduce its power requirements. This will likely rely on an underground LTE network.

“Heating of the underground mine and surface facilities is designed with the assumption of propane burners, but an opportunity exists to extend the natural gas line to the project site,” it added. “Yamana has initiated discussions with the natural gas supplier and will study this opportunity further as the project advances.”

The site for the processing plant and offices is confined to a small footprint strategically located in a naturally concealed area, and the processing plant has been designed with a low profile to minimise the visual impact as well as minimise noise and dust, according to Yamana.

The primary crusher, previously planned to be located on surface, has been moved underground, with the crushed material transported to surface from the underground mining area using conventional conveyors and stored on surface in a covered stockpile to control dust.

Several design improvements to the previous Wasamac plans have also been made to reduce consumption of fresh water to minimise the effect on watersheds, according to Yamana. Underground mine water will be used in the processing plant, minimising the draw of fresh water and reducing the required size of the mill basin pond.

The Wasamac tailings storage strategy is designed to minimise environmental footprint and mitigate risk, it added.

“Around 39% of tailings will be deposited underground as paste fill and 61% of tailings will be pumped as a slurry to the filter plant located approximately 6 km northwest of the processing plant and then hauled to the nearby dry-stack tailings storage facility,” Yamana said.

Strategic phasing of the tailings storage facility design allows for the same footprint as previously planned, even with the increase in mineral reserves, the company clarified. Also, the progressive reclamation plan for this facility minimises the possibility of dust generation and expedites the return of the landscape to its natural state.

Howden causes a fanfare with launch of Jetsteam AX

Environmental, IoT, Mine ventilation, Mining equipment, Mining services, Power supply for mines, , , , , , , , , ,

Howden is looking to re-enter the Australian secondary ventilation market with a bang, coming out with a new product that offers the energy efficiency, durability and smarts to help ‘future proof’ underground mines.

Its Jetstream AX secondary fans were launched across the globe this month, with service centres on the east and west coast of Australia having already received units.

Phil Durham, Global Mining Applications Engineer, said the Jetstream AX secondary fan is the missing piece to complete the full Howden ventilation puzzle.

“Howden, in the past, was heavily involved in the secondary market in Australia, but some years after exiting this space, the new Jetstream AX is filling the gap in our lineup, helping complete our total mine ventilation solution approach,” he told IM. “Howden has the Ventsim™ DESIGN software, the Ventsim CONTROL ventilation on demand software, plus all the required equipment including a comprehensive primary fan offering, mine cooling options and mine heating options.

“A global secondary fan was needed to complete the set, meaning we can now be considered a one-stop shop for miners wanting to go down the full Howden route for ventilation.”

While the Jetsteam AX will be available in all markets – bar USA where Howden already has a secondary fan offering – Howden sees it being particularly relevant for the Australian market where evolving diesel particulate emission regulations are making effective ventilation operations a must.

“These regulations will definitely affect how those mines manage, monitor and control their ventilation network,” Durham said. “The smart move would be to use their secondary fans more efficiently in terms of how and where they are locating them, which ones are operating and tightening up on where the working areas, vehicles and personnel are.

“In this respect, the Australia region is a key one in terms of the secondary fan product rollout.”

Just some of the attributes the region’s miners could benefit from, according to Howden, include:

  • The highest fan output at low power consumption, providing high efficiencies across a broad operating range;
  • A range of fans from 762-1,600 mm in diameter, with flow rates from 6.5-108 cu.m/sec;
  • Single-stage or twin-stage configuration;
  • A flexible modular design providing commonality of parts;
  • Adjustable pitch aerofoil blades to maximise operational envelope and provide reliable high-efficiency aerodynamic performance across a wide range;
  • An anti-stall chamber for continued safe operation during transient high-pressure events, offering a “risk-free process” in parallel fan arrangements; and
  • Downstream guide vanes with full inner fairing tube and tail cone in each fan to ensure maximum static pressure regain.

Durham expanded on some of these.

“That main inner fairing tube serves a couple of purposes, with one of the main ones being a reduction in shock losses,” he said. “That same design helps from a maintenance perspective, too, providing protection for the motor. In other ventilation fan designs, the motors are exposed to the dusty mine air. The inner tube provides a good level of protection, without being a totally sealed environment. Some air gets through for motor cooling purposes, but it is much less than your typical exposed fan.”

The option of a dual-speed fan could also be important for gaining sales in Australia given there are limited variable speed drive options in this market than others, according to Durham.

“In Australia, specifically, variable speed control is not a very common option due to the required 1,000 V supply,” he said. “Currently there are no proven reliable variable speed drives at such voltages.”

This dual-speed fan offering provides the mines with high and low speed settings – with high typically employed to, for example, clear blasting gases and low employed when a vehicle leaves the airway, and the ventilation demand reduces.

To get the best out of dual-speed fans, mines will most likely require remote access to easily switch from one setting to the next, according to Durham.

Miners that understand the benefits of using dual-speed fans – reducing energy consumption and costs – will also, most likely, be potential customers for Howden’s ventilation on demand and smart ventilation solutions, namely Ventsim CONTROL.

“We are definitely seeing an increase with the number of mines looking to adopt these new technologies and smarter ventilation control methods,” Durham said. “As they are moving towards digitalisation and automation of mining methods, ventilation is also coming into that equation. This is especially so when you consider that the energy cost coming from ventilation and cooling can be around 50% of the mine’s total expense.”

The use of effective secondary fans is part of that exercise, according to Durham, who said efficiencies of over 85% are possible with these units when used optimally.

“Although the primary fans are generally a much higher kilowatt rating, these mines usually have quite a number of secondary fans in operation,” he said. “Being able to use them in a smarter way on a day-to-day basis means they will be able to make some large savings there.”