Tag Archives: ventilation on demand

Yamana Gold retains electrification path for Wasamac in new study

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

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.”

Barrick continues to adopt new technologies at Kibali gold mine

Barrick Gold says its 45%-owned Kibali gold mine in the Democratic Republic of the Congo is continuing its technological advances with the introduction of truck and drill training simulators and the integration of systems for personnel safety tracking and ventilation on demand.

The mine, which is owned 45% by AngloGold Ashanti and 10% by SOKIMO, surpassed its 2019 guidance of 750,000 oz in 2019, delivering 814,027 oz in another record year, Barrick said this week.

Barrick President and Chief Executive, Mark Bristow, told a media briefing that Kibali’s continuing stellar performance was a demonstration of how a modern, Tier One gold mine could be developed and operated successfully in what is one of the world’s most remote and infrastructurally under-endowed regions.

He also noted that, in line with Barrick’s policy of employing, training and advancing locals, the mine was managed by a majority Congolese team, supported by a corps of majority Congolese supervisors and personnel.

Kibali is already one of the world’s most highly automated underground gold mines, with the operation’s backbone being Sandvik’s Automine Multi Fleet system, supervised on surface by a single operator. In a world first, it allows a fleet of up to five LHDs to be operated autonomously, 750 m below the surface, within the same 6 m x 6 m production drive while using designated passing bays to maintain traffic flow, the company says. A similar system is used in the production levels to feed the ore passes, according to Barrick.

The company said it had now introduced truck and drill training simulators and integrated systems for personnel safety tracking and ventilation demand control, adding that the simulators will also be used to train operators from Barrick’s Tanzanian mines.

Bristow also said that the company was maintaining a strong focus on energy efficiency at the mine through the development of its grid stabiliser project, scheduled for commissioning in the June quarter of 2020.

He said: “This uses new battery technology to offset the need for running diesel generators as a spinning reserve and ensures we maximise the use of renewable hydro power. The installation of three new elution diesel heaters will also help improve efficiencies and control power costs. It’s worth noting that our clean energy strategy not only achieves cost and efficiency benefits but also once again reduces Kibali’s environmental footprint.”

Bristow said despite the pace of production and the size and complexity of the mine, Kibali was maintaining its solid safety and environmental records, certified by ISO 45001 and ISO 14001 accreditations.