Tag Archives: Mine ventilation

Tata Steel’s Jharia Division receives coal prep plant, ventilation power supply boost

In line with its mechanisation and modernisation program, Tata Steel’s Jharia Division has commissioned a “state-of-the-art” 2 Mt/y coal preparation plant and 400 kVA uninterrupted power supply (UPS) for the main ventilation fan at the Jamadoba Colliery in India.

On the occasion, D B Sundara Ramam, Vice President (Raw Materials), Tata Steel, said: “Introduction of appropriate technology is key to the success of underground mining. At Tata Steel, we leverage our innovation capabilities, technology leadership with focus on safety and sustainability to create long-term value. This state-of-the-art beneficiation plant not only addresses issues like productivity, safety and environment but, at the same, time ensures production of coal at a competitive price.”

Built using cutting-edge technology, the 2 Mt/y preparation plant has been transformed from the oldest running washery in Asia (in operation since 1952) to one of the most modern washeries across the globe, Tata Steel said.

The washery is a major upgrade from the conventional set-up, consisting of a dense media separation cyclone circuit for coarse material, reflux classifier for the intermediate circuit and flotation for the fines circuit – all geared towards improving production efficiency. This is also the first washery in the country with a 100% dewatering facility built within its plant, thereby completely eliminating the need for a tailings pond, auto sprinklers and dry fog systems.

The giant UPS provides uninterrupted power supply to the 450 hp (336 kW) mine fan and automatically changes over during power failure from DVC, keeping the fan running for 40 minutes – enough time for power restoration or change-over to captive supply. This battery back-up UPS is the first-of-its-kind in the country for any mine ventilation fan, according to Tata Steel, enhancing the safety and ergonomics within the mines and providing a more comfortable environment for the miners to work.

Tata Steel says its Jharia Division has been at the helm of innovation and modernisation since its inception, with initiatives like its chair lift man riding system, cooling plant, low capacity and low cost continuous miner with the haulage system setting benchmarks when it comes to underground mining in the country. The Jharia Division has undertaken several initiatives of automation and digitalisation which has helped in improving operational excellence.

Howden boosts Ventsim CONTROL functionality with ‘cooling on demand’

Howden is continuing to expand its flagship Ventsim CONTROL software, with the latest update to the ventilation control platform set to bring an ‘on demand’ element to mine ventilation cooling.

An upgrade from Ventsim DESIGN, Ventsim CONTROL uses intelligent software connected to Howden or third-party hardware devices to remotely monitor, control and automate airflow heating and cooling to deliver safer, more productive, and lower cost ventilation for mines, the company says.

Hugo Dello Sbarba, Director of Ventsim and Sales Mining, says the addition of a ‘cooling on demand’ module to Ventsim CONTROL coincides with an industry move to install more mine cooling plants to achieve higher standards of health and safety for workers. Howden has seen this trend up close and personal, having recently successfully delivered the first phase of an 8 MW surface bulk air mine cooling plant for Roxgold’s Yaramoko gold mine in Burkina Faso.

“We chose now to introduce cooling on demand to Ventsim CONTROL partially because more mines are getting deeper, require cooled air and are adopting higher standards in advance of incoming regulations,” he told IM. “This reflects a wider industry move towards more sustainable operations.”

There was also a push from existing Ventsim CONTROL customers for such cooling functionality, according to Dello Sbarba, with these clients realising the benefits that could come with controlling the process from the underground readings, assessing where cooling was most needed.

“While the actual capital cost associated with the cooling plant installation is unlikely to change – given these plants should be sized by engineers on a worse-case scenario basis – you should definitely see significant improvements in terms of the operating and energy cost of the plants,” he said.

This economic benefit is complemented by the health and safety advantages already mentioned.

“At the moment, miners tend to put a chilling plant on surface and just cool the air regardless of where it is destined to go,” Dello Sbarba said. “This process doesn’t consider the fact that the only reason you are cooling air on surface is for the deeper levels of the mine that experience particularly high temperatures.

“You currently don’t have intelligent control of this cooled air across the underground mine.”

With Howden’s cooling on demand module within Ventsim CONTROL, users can monitor if they are obtaining the required temperatures at these deeper levels, making sure the cooled air is pushed to where it needs to go.

Aside from a subscription to Ventsim CONTROL with at least Level 3 and 5 functionality – providing required set points for airflow, gas levels, and/or temperature – and the right-sized ventilation fans, users only require temperature and humidity sensors underground to carry out such control.

“Even though you need many of these monitors, they are relatively cheap with many hardware solutions available on the market,” Dello Sbarba said.

Equipped with these elements, users can assign certain temperature/humidity setpoints in areas of high activity, plug these setpoints into Ventsim CONTROL and allow the software to ‘communicate’ with the cooling plant and fans to automatically cool these areas to the required temperature. An advanced Level 5 installation of Ventsim CONTROL allows users to automatically optimise underground fan and regulator settings and adjusting main fan settings to maintain required cooling levels while maximising energy savings.

He concluded: “The reason it is advantageous to perform cooling on demand with Ventsim CONTROL over other solutions is the 3D modelling capabilities within the software. The model helps you predict and better control your air flows based on what you are seeing in the simulation.

“It has an edge over any other custom-made ventilation engineering solution on the market.”

The new cooling on demand functionality is now in the final throes of testing in a factory setting, with a mine site trial being lined up for later in the year.

Howden delivers mine cooling plant at Roxgold’s Yaramoko mine

Howden says it has successfully delivered the first phase of an 8 MW surface bulk air cooling plant for Roxgold’s Yaramoko gold mine in Burkina Faso.

The Yaramoko Mine Complex is in a remote region of Burkina Faso, 200 km southwest of Ouagadougou.

The cooling plant is designed to deliver a maximum of 190 cu.m/s of chilled downcast ventilation air, with the air cooled from a design ambient temperature of 25.8°C, down to 15°C.

The plant comprises an open-spray vertical bulk air cooler located on top of the shaft collar, centrifugal chillers and conventional cooling towers, Howden explained.

Plant design and construction were started at the beginning of 2020 during the early onset of the COVID-19 pandemic, and, despite a challenging environment, Howden successfully delivered the project’s first phase in May.

Howden said: “This latest project continues to positioning Howden as a process and system specialist to design, supply and install mine cooling systems. Howden has a technology-neutral approach whereby technology options are offered which best suits customer’s technical and commercial requirements.”

The Yaramoko Mine Complex, which consists of two underground operations, delivered production of 35,308 oz of gold in the March quarter, Roxgold reported in May.

Howden boosts mine ventilation offering with VortexOHS occupational hygiene collaboration

Howden has signed a new partnership with VortexOHS™, a modular ventilation and occupational hygiene data collection and management system.

This partnership, Howden says, further strengthens the ventilation expert’s commitment to mine ventilation solutions for the health and safety of customers worldwide.

Howden’s Ventsim Design and Ventsim Control products help ensure mines can efficiently design and provide airflow, heating and cooling to underground environments offering a safe atmosphere for workers. At the same time, VortexOHS further improves safety by assisting ventilation and occupational hygiene professionals to collect, manage and report data and information from their occupational health and safety (OH&S) sampling programs.

The partnership is a perfect fit for Howden’s mission to offer new safety solutions and achieve excellence in mine ventilation design, monitoring, and control, the company said.

Howden’s Hugo Dello Sbarba said: “Ventsim accurately models, designs, controls, evaluates, and optimises underground mine ventilation systems. Expanding Ventsim capabilities to incorporate VortexOHS’ innovative solutions provides a powerful tool for mine operators to improve safety and ensure compliance with regulations.”

VortexOHS’ Shane Ambrosio said: “I have enjoyed assisting mines in improving the efficiency and speed of their OH&S system and reporting. We are looking to continue building the existing VortexOHS success, thanks to the collaboration with Howden and the Ventsim suite of products integration.”

Automation, electrification, alternative haulage weighed for GSR’s Wassa UG expansion

A preliminary economic assessment (PEA) on the potential expansion of Golden Star Resources’ Wassa gold mine in Ghana has flagged the potential for applying alternative underground haulage methods, and autonomous and battery-electric equipment at the operation.

The PEA provides an assessment of the development of the Southern Extension of Wassa and the increase in mining rates to fully use available process plant capacity. While the study itself represents a conservative plan that excludes exploration opportunities from the scope and adopts the current mining practices and equipment, the “opportunities” section of the technical report outlines some more innovative approaches to expanding mining rates and filling the plant capacity.

Wassa, which Golden Star owns 90% of, produced 168,000 oz of gold in 2020 using the sub-level longhole open stoping method.

The PEA is focused on the development of the large inferred mineral resource (just over 7 Moz) which comprises the Southern Extension zone. Around 50% of the total resource was included in the PEA inventory, which showed off a life of mine of 11 years, with total gold production of 3.5 Moz. Average annual gold production of 294,000 oz represented an approximate 75% increase on the current production rate.

The mine plan considers a production rate targeting the processing capacity, at or close to 2.7 Mt/y run-of-mine material, after a five-year ramp-up period. The plant has previously operated at these rates with feed from both Wassa and the Bogoso-Prestea operation (since sold).

Mining would be by underground trackless decline access (1:7 gradient), with access from duplicate access ramps and independent ventilation infrastructure on each side of the deposit to support the increased mining rate and provide efficient access across the mineralised footprint (circa-850 m along circa-300 m across strike). Truck haulage will utilise the dual access ramps.

The mining method proposed for the expansion is bottom-up long hole open stoping with 25 m level spacing and nominal stope sizes of 25 m length x 30 m width x 25-100 m height with cemented paste backfill. Stopes will be mined in a primary-secondary sequence down to around 1,000 m depth, transitioning to pillarless retreat below that point to account for increasing in-situ stress, which will need to be further investigated in future work.

The PEA assumes average recovery of 94.8%, which is supported by current plant performance and metallurgical test work on a small number of samples that suggest processing performance for the Southern Extension feed will be similar to material currently treated. This will be evaluated in the next phase of work.

Capital expenditure is expected to total around $790 million over the life of the PEA mine plan. Of this total, 29% is growth capital and 71% is sustaining capital. The PEA mining method relies on paste fill, with Golden Star confirming the paste fill plant was constructed in 2020 and commissioning is expected to be finalised this quarter. Capital has been allowed for an expansion of the paste fill system in the PEA mine plan.

Based on a $1,300/oz gold price, the expansion project is expected to generate a post-tax net present value (5% discount) of $452.2 million.

So far, so conventional…

The company said it planned to complete option and trade-off studies to optimise the project plan ahead of a feasibility study on the expansion, due in early 2023.

Just some of the innovations being considered in these trade-off studies include the use of automation, electrification and alternative haulage.

In terms of increasing machine productivity through technology, the study listed off the potential use of semi- or fully-autonomous vehicles to increase shift operating time and remove operators from hazardous areas. It said the highest likelihood applications were in production drilling and drawpoint loading.

Golden Star confirmed current projects included in its in-development technology roadmap were the introduction of tele-remote loading and digitalisation of production data.

In terms of haulage infrastructure opportunities, Golden Star said it was considering the replacement of truck haulage with an infrastructure system like shaft hoisting, conveyor, or Rail-Veyor. The capital demand for such options would be offset by a large reduction in operating costs with automated systems, reduced diesel consumption and reduced ventilation demand, it noted.

These haulage options were being studied to design different systems, estimate capital and operating costs, then complete a trade-off analysis, the company said.

The current mine design assumes loaders digging from open passes to load trucks, but Golden Star said feeder systems could be installed to automate loading, increasing efficiency and reducing operating costs.

And, of course, the company said it was considering options for clean energy technology applications, particularly battery-electric trucks. As part of this, it was assessing available systems and developing fleet selection criteria. This will have knock-on benefits to the mine’s ventilation requirements.

TLT-Turbo customised ventilation solution hits the spot at South Africa mine

TLT-Turbo Africa says its customised and proactive approach to ventilation solutions, combined with a new range of auxiliary and booster fans, have provided substantial electrical cost savings to a major global gold and platinum producer.

The latest installation comes just three months after installing a customised pair of TLT-Turbo Africa’s fans at one of the miner’s South Africa sites.

TLT-Turbo Africa was approached by the ultra-deep mining operation, in Gauteng, requiring a recommendation for a suitable fan solution to be installed in a section of its mine.

“Following numerous engagements, our engineering and research and development teams set out to develop a customised solution utilising our high efficiency A&B fan range,” Vusi Madlopha, TLT-Turbo Africa Head of Sales & Business Development, said.

TLT-Turbo Africa’s solution was purpose-designed to meet the requirements of the mining operation. At the time, the operation was using multiple installations of auxiliary fans to deliver the required volume and pressure (these auxiliary fans were consuming circa-630 kWe). The mine was also operating three main surface fans, each consuming around 2 MW of power.

“The client’s main objective was to ensure that a sufficient volume of ventilating air was provided to the underground operations while reducing power consumption,” Madlopha explained. “To meet their needs, TLT-Turbo Africa was required to supply two fans, each capable of moving 71 cu.m/s of ventilating air at a pressure loss of 3,000 Pa.”

These requirements fell comfortably within the design ranges of TLT-Turbo Africa’s A&B fan offering, the company said.

Based on an assessment of the mine’s needs, the final recommendation made by TLT-Turbo Africa was for two MC1600AP-160 kW dual-stage fans from the newly launched A&B fan range (specifically 1,600 mm diameter, dual-stage fans, each fan driven by two 160 kW high-efficiency motors).

There was another challenge TLT-Turbo’s team was required to resolve; the selected fans (as per standard, off-the-shelf design) would be too large to pass freely through the shaft and horizontal infrastructure to reach their installation site.

To overcome this obstacle, TLT-Turbo Africa’s R&D team custom designed the fans to be modular thus allowing transport of the fan components through the shafts and access tunnels of the mine. Once on site, the fans were easily assembled, according to Madlopha.

The complete product offering also included broadband silencers, self-closing doors and other fan ancillaries. For this project, TLT-Turbo Africa also provided locally manufactured Direct On-line starter panels.

“TLT-Turbo Africa offered the mine a solution well suited to the tough underground mining environment,” Madlopha said. “This solution would ensure a reliable supply of ventilation within the section of the mine in which the fans were to be installed.”

Three months after the installation and commissioning of the supplied fans, conditions underground at the shaft have improved noticeably, according to Madlopha. This is particularly the case in the previously warmer upper levels.

The installation and commissioning of the TLT-Turbo Africa fans described above has allowed the mine to permanently stop and remove 14 other auxiliary fans (with a total rated power of 630 kW). In addition, the mine has also been able to permanently stop one of the main surface fans, resulting in a direct energy saving of more than 2 MW of power, providing an annual electrical cost saving of more than ZAR14 million ($921,504). The capital payback period on this project has been less than three months, according to TLT-Turbo Africa.

“With the lifespan of this project exceeding 10 years, the implied electrical cost savings of this solution are massive,” the company said.

According to Madlopha, the success of the ventilation equipment at this mine can be attributed to the innovative design of the company’s A&B fan range, and the ability of TLT-Turbo’s experts to customise these fans even further to meet client and site-specific requirements.

“The system supplied was customised and optimised for that particular operation,” Madlopha said. “The design point, layout and robust structure provided an overall fan system which is not only efficient, but also reliable.”

Minetek to deliver ventilation solution to Mincor’s Kambalda nickel ops

Minetek says it has been awarded a tender to supply the ventilation requirements for the Cassini, Otter Juan and Long declines at Mincor’s Kambalda nickel operation in Western Australia.

The award, which came through Mincor’s contracting partner, Pit N Portal, includes both the secondary and primary vents across all three declines and follows on from a close collaboration over the last six months between the three parties, Minetek says.

Steve Verstegeen, CEO for Pit N Portal, said: “We are always looking at new innovations and technologies that will benefit both us and our clients. Minetek has been able to display that with the use of their modern ventilation technology, where we can look to see production increases through faster re-entry times and reduced capital costs in the total life of the development, delivering value to both us and Mincor.”

Minetek General Manager – Ventilation, Jeremy Sutherland, said: “From the start of early discussions with Mincor and Pit N Portal, it was very evident that both parties wanted to deliver the maximum amount of value for their stakeholders/shareholders in all aspects of the developments. This really excited our team, as it gave us the opportunity, through the release of forecasted production information and mine plans from Mincor and Pit n Portal, to display that we could deliver this through energy savings, production increases and reduced capital expenditure throughout the lifecycle of the developments.”

The “Mincor Nickel Operations” DFS from earlier this year confirmed the potential to develop a five‐year operation forecast to produce 71,000 t of nickel and 5,000 t of copper on a life-of-mine basis at Kambalda, with peak annual nickel-in-concentrate production of more than 16,000 t/y at a forecast life of mine unit cost of $2.35/lb.

RUC Mining, Barminco keep Panoramic’s Savannah nickel restart plan on track

Panoramic Resources says underground development at the Savannah nickel project in Western Australia is moving ahead as planned, with both its raisebore contractor and contract miner striving towards the ASX-listed company’s first half 2021 restart goal.

In a progress update, the company said mining contractor, Barminco, had completed the 468 m horizontal underground development drive, connecting with the vertical ventilation shaft to complete Fresh Air Raise (FAR #3) development at Savannah North, in late September.

Since then, specialist raiseboring contractor, RUC Mining, has been setting up the raisebore rig on the surface and installing the reamer head at the 1675 RL, which was developed to intersect into the existing FAR #3 raise.

“This complicated and critical task was completed safely and efficiently as planned,” Panoramic said on October 19. “RUC is tasked with the FAR #3 back-reaming, which commenced over the weekend and expected to be completed in the March 2021 quarter.”

A total of 354 m will be back reamed at a diameter of 3.85 m, according to the company. This is planned to provide sufficient ventilation to support future full-scale mining operations from Savannah North in line with the Mine Plan released in late July.

Managing Director and CEO, Victor Rajasooriar, said: “We now have a firm foundation to recommence underground pre-production development next month, to complete ventilation works for Savannah North and complete areas of capital development to lay further groundwork for a potential restart of operations. This work will be concluded towards the end of the March quarter 2021 and we expect to be in a position where the project is capable of being restarted in the first half of 2021.”

The Savannah Mine Plan outlined a mine life of around 13 years, with the majority of ore sourced from the Savannah North orebody. Average annual production for years 1-12 would be 8,810 t of nickel, 4, 579 t of copper and 659 t of cobalt in concentrate, with all-in costs for these years of $5.27/lb of payable nickel, net of copper and cobalt by-product credits.

DSI Underground and ABC Canada form underground ventilation JV

DSI Underground has signed a new joint venture agreement with ABC Canada to, the companies say, strengthen the safety level for underground mining and tunnelling.

On September 1, DSI Underground Ventilation Systems was officially launched.

The product portfolio of the new joint venture will include Flexline™ and semi-rigid Hardline™ flexible vents for positive and negative airflow, high-efficiency Toughvent fans, and other ventilation accessories: curtains and coverings, emergency shelters, inflatable airstop and repair kits, the companies said.

In addition, the joint venture will have a team of engineers specialising in the design of ventilation systems, capable of providing advice and the necessary technical support, increasing the level of safety and profitability of the projects by optimising energy. The company is a direct manufacturer of supplies and fabrics, ensuring the products meet the highest technical and quality standards required, they said.

DSI Underground Ventilation Systems will start operations in Santiago, Chile, with a production plant of more than 2,000 sq.m and will be present in the Latin America region, directly through entities in the region and with an exclusive distributor in Colombia.

“We are confident that this new company will allow us to deliver more efficient and comprehensive solutions to our customers and will enable us to continue to reinforce progress in underground mining and tunnelling,” the companies said.

WEG helps ventilate MMK’s Chertinskaya-Koksovaya mine in Russia

WEG Electric CIS, a subsidiary of WEG based in St Petersburg, has been awarded a contract to supply two flame-proof motors for the primary ventilation system of the Chertinskaya-Koksovaya mine in Russia.

Partnering with Ventprom, a manufacturer of underground ventilation equipment, WEG has developed unique, explosion-proof motors to meet the challenging conditions of a large-scale mining environment, it says.

The Chertinskaya-Koksovaya mine, in Belovo, is managed by MMK-Ugol, which produces around 3.4 Mt/y of coal, 2.8 Mt of which is used for steel production.

Working with Ventprom, WEG has designed a new motor that has been manufactured specifically to operate in this environment, it said.

Due to the nature of the Chertinskaya-Koksovaya environment, off-the-shelf motors would not suffice, according to WEG. To overcome this, WEG applied its expertise in motor design to develop a bespoke solution, with increased lifespan compared with more generic motors.

Using a tube-cooling design, WEG came up with two flame-proof motors that could operate effectively when fully enclosed. As opposed to air cooling, the motors minimise heat by using cooling tubes inside the motor’s frame.

As part of the commission, WEG also developed a unique bearing arrangement to endure the high loads and inertia of the application. The two flame-proof motors, which operated at an output of 2,400 kW, were customised specifically for deployment in the mining environment.

The two motors meet Customs Union certification, a standard for countries in the Commonwealth of Independent States. The motors also adhere to EACEx standards, the Eurasian conformity certification for explosion-proof products, according to WEG.

They were designed and manufactured for Chertinskaya-Koksovaya by WEG Portugal at one of the company’s European manufacturing facilities in Maia. The factory is one of two production sites in Portugal and specialises in the production of explosion-proof motors.

Ihor Sapa, Business Development of Russia and CIS countries at WEG Portugal, said: “Customised products are not necessarily a luxury, but a necessity in some sectors. For this project, developing a bespoke motor was essential. In the environment of the Chertinskaya-Koksovaya mine, the motors needed to be flame-proof and expertly designed.

“Thankfully, WEG Portugal is highly experienced in the manufacture of explosion-protected solutions.

“WEG’s customer-focused approach and the attention given to customers’ individual needs proves that WEG is prepared to address the requirements of unique and complicated projects – including underground mining and classified area products.”