Tag Archives: Fekola

Suntrace, BayWa re, B2Gold commission ‘world’s largest’ off-grid solar-battery system

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Suntrace GmbH and BayWa re, together with B2Gold, have completed commissioning of what they say is the world’s largest off-grid solar-battery hybrid system for the mining industry at the Fekola gold mine in Mali.

The solar-battery hybrid plant was integrated and commissioned successfully with the existing power plant operation, with the solar plant on course to be 100% complete by the end of June.

Hybrid projects such as this, which combine solar energy with conventional energy generation and battery storage, are an effective way to provide reliable power supply day and night in off-grid areas, Suntrace says. “Ideally suited to their needs, B2Gold approved the hybrid project for implementation in July 2019, following completion of preliminary studies by Suntrace and BayWa re.”

The Fekola gold mine operates 24-hours a day. During the daytime, the new 30 MW solar plant allows three out of six heavy fuel oil generators to be shut down; the energy production of the residual three generators could also be significantly reduced. The 15.4 MWh battery storage compensates for energy generation fluctuations and assures a reliable operation, which allows up to 75% of the electricity demand of the gold mine to be covered by renewable energy during the daytime, Suntrace said.

Dennis Stansbury, Senior Vice President at B2Gold, said: “Suntrace and BayWa re have played a vital role in our work towards more sustainable production at Fekola. The implementation of a solar-battery hybrid system was an obvious choice to help achieve this, not only for its environmental credentials, but also its economic viability. This is a landmark project which we expect to pave the way for more sustainable power generation within the mining industry in West Africa.”

The integration of the solar power plant with the battery system will ensure safe and reliable power, saving 13.1 million litres of heavy fuel oil a year.

Martin Schlecht, COO of Suntrace, said: “We are very proud that B2Gold has entrusted Suntrace, together with BayWa re as engineering and procurement contractor, to support the development and implementation of this innovative project. Thanks to excellent team work with B2Gold and BayWa re, we were able to manage the completion despite the global challenges that the COVID-19 pandemic imposed on all of us. We are proud to jointly deliver a functioning project, well integrated with the mining operations, which reduces CO2 emissions from power generation for the Fekola mine by roughly 20%.”

The photovoltaic-battery system will help to reduce CO2 emissions by 39 000 t/y, according to the company.

Thorsten Althaus, Project Manager at BayWa re, added: “Integrating such a large amount of solar into a small, isolated grid safely and reliably has been a major technical challenge and required the use of battery storage as well as a tailor-made control system. This was conceptualised in the early stages of the project and we ensured that our vision was implemented accordingly by the suppliers. It is extremely rewarding to see how well this solution performs in reality and shows that the technology works and is just waiting to be applied on further projects.”

Optimising energy management at B2Gold’s Fekola mine

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The delivery of a cutting-edge 17 MW/15 MWh energy storage platform and Wärtsilä’s advanced GEMS system is optimising energy management at B2Gold’s Fekola gold in Mali, Luke Witmer* writes.

Since B2Gold first acquired the Fekola gold mine, located in a remote corner of southwest Mali, exploration studies revealed the deposits to be almost double the initial estimates.

A recent site expansion has just been completed, and while the existing power units provide enough power to support the increase in production, the company sought to reduce its energy costs, cut greenhouse gas emissions, and increase power reliability.

The addition of a 35 MWp solar photovoltaic (PV) plant and 17 MW/15 MWh of energy storage to the existing 64 MW thermal engine plant was decided. This new energy mix is anticipated to save over 13 million litres of fuel, reduce carbon emissions by 39,000 t/y, and generate a payback in just over four years.

Such an elaborate hybrid configuration needs a powerful brain to deliver on all its potential: Wärtsilä’s GEMS, an advanced energy management system, has been set up to control the energy across the fleet of power sources, thermal, renewable, and battery storage. The integration, control, and optimisation capabilities provided by GEMS allow the thermal units to be run at the most efficient rate and enable the battery storage to handle the large load step changes and volatility of the solar PV generation assets.

Integrated hybrid energy solution

In the context of the Fekola mine, which is an off-grid electrical island, the battery is performing a lot of different services simultaneously, including frequency response, voltage support, shifting solar energy, and providing spinning reserves. The energy load is very flat, with a steady consumption rate around 40 MW as the mining equipment is operating consistently, 24/7. However, if an engine trips offline and fails, the battery serves as an emergency backstop. The controls reserve enough battery energy capacity to fill the power gap for the time it takes to get another engine started, and the software inside each inverter enables the battery to respond instantaneously to any frequency deviation.

The reciprocating engines operate most efficiently at 85-90% of their capacity: this is their ‘sweet spot’. But if there is a sudden spike in demand, if a little more power is needed, or if mining equipment is coming online, then another engine needs to be run to meet the extra load.

With the battery providing spinning reserves, the engines can be kept running at their sweet spot, reducing the overall cost per kilowatt hour. Moreover, with the solar plant providing power during the day, three to four engines can be shut down over this period, providing a quiet time to carry out preventive maintenance. This really helps the maintenance cycle, ensuring that the engines operate in a more efficient manner.

Solar PV volatility can be intense. On a bright day with puffy clouds passing by, a solar farm of this size can easily see ramps of 25 MW over a couple of minutes. This requires intelligent controls, dynamically checking the amount of solar that can be let into the grid without causing an issue for the engine loadings or without overloading the battery.

Conducting the orchestra

The GEMS intelligent software provides the optimisation layer that controls all the power sources to ensure that they work together in harmony. The user interface (UI) gives access to all the data and presents it in a user-friendly way. Accessible remotely, all operations are simulated on a digital twin in the cloud to verify the system controls and simulate the most efficient operating scenarios to lower the cost of energy.

This is an important software feature, both during and after commissioning as it allows operators to train on the platform ahead of time and familiarise themselves with the automated controls and dynamic curtailment of renewables. The UI provides the forecast for renewables and the battery charge status at any given moment, it can provide push email or phone notifications for alerts; telling operators when to turn off an engine and when to turn it back on.

The software is constantly analysing the data and running the math to solve the economic dispatch requirements and unit commitment constraints to ensure grid reliability and high engine efficiency. Load forecasting integrates the different trends and patterns that are detectable in historic data as well as satellite based solar forecasting to provide a holistic approach to dispatching power. The Fekola site has a sky imager, or cloud tracking camera with a fisheye lens, that provides solar forecasts for the next half hour in high temporal resolution.

To ensure that operators really understand the platform, and have visibility over the advanced controls, the UI provides probability distributions of the solar forecast. Tracking the forecast errors enables operators to see whether the solar is overproducing or underproducing what the forecast was expecting at the time and provides visibility to the operators on the key performance indicators. This feedback is an important part of the machine/human interface and provides operators with insight if an engine is required to be turned on at short notice.

Automated curtailment enables the optimisation of the system providing a reactivity that people cannot match. By continually monitoring the engine loadings and battery, the system is ready to clamp down on solar if it gets too volatile or exceeds some spinning reserve requirement. For example, if a large, unexpected cloud arrives, the battery is dispatched to fill the gap while the engines ramp up. Once the cloud disappears, however, the engines remain committed to operating for a few hours, and the solar power is transferred to recharge the battery.

Over time, as load patterns shift, the load forecasting algorithm will also be dynamically updating to match the changing realities of the load. As mining equipment hits layers of harder rock, increasing the power load, the system will adjust and dispatch the engines accordingly.

The new gold standard

The Fekola mine project incorporates the largest off-grid hybrid power solution in the world, demonstrating the growing case for clean energy and its sustainable and economic potential for mines in Africa and beyond.

As the cost of batteries and solar panels continues to become more competitive, hybrid solutions are proving to be a realistic and effective means for increasing energy reliability and lowering operating costs in any context, thus freeing up resources to improve the human condition; whether through cheaper materials and gainful employment, or by providing broader access to reliable electricity for healthcare, education, and improved quality of life.

*This piece was written by Luke Witmer, General Manager, Data Science, Wärtsilä Energy Storage and Optimization

B2Gold’s Fekola mine expansion starts up ahead of schedule

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B2Gold Corp has successful commissioned the mill expansion at the Fekola mine, in Mali, to 7.5 Mt/y, around one month ahead of the scheduled completion date of September 30, 2020.

The company has completed all major construction activities associated with the Fekola mill expansion, as well as successful execution of a process performance test to compare with design expectations, it said.

Four days after start-up, a five-day mill performance test was conducted from August 26 to August 30, 2020. The results of the performance test exceeded design in throughput, gold recovery, grind and availability over the period. The minor, outstanding construction work is expected to be completed by mid-September 2020, it said.

The expansion has seen the company expand the mining fleet (adding excavators, trucks, and drill rigs); bolster the mill with cyclone clusters, leach and CIP tanks; and complete a double lift on the tailings storage facility.

This has already had an impact on the mine’s core metrics. In the first half of the year, Fekola produced 311,435 oz of gold, 7% above budget and 39% higher than the first half of 2019.

B2Gold acquired Fekola through a merger with Papillon Resources in October 2014, with the company completing construction of the Fekola mill and commencing ore processing more than three months ahead of the original construction schedule and on budget, in September 2017.

The first gold pour at Fekola took place on October 7, 2017. Within only 60 days from start-up, the mine achieved commercial production on November 30, 2017, one month ahead of the revised schedule and four months ahead of the original schedule.

B2Gold to soak up solar power at Fekola gold mine

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B2Gold, in its June quarter results, has provided an update on its plans to install a solar plant at its Fekola gold mine in Mali.

The company said it completed a preliminary study to evaluate the technical and economic viability of adding a solar plant to the site, during the quarter, with the results indicating it was a very “solid project” and that a plant of around 30 MW of solar generating capacity with a significant battery storage component would provide the best economic result.

A second study has now been completed to establish the detailed capital and operating cost analysis for the project. Results indicated that a solar plant can provide significant operating cost reductions (estimated to reduce processing costs by some 7%), with the project approved by the B2Gold Board in the June quarter.

The company said: “The Fekola Solar Plant will be one of the largest off-grid hybrid solar/heavy fuel oil (HFO) plants in the world.

“It is expected that it will allow for three HFO generators to be shut down during daylight hours, which will save about 13.1 million litres of HFO per year, at a capital cost of approximately $38 million, of which $20 million is expected to be incurred in 2019, with the balance in 2020.”

The solar plant is scheduled for completion in August 2020 and has a four-year payback, B2Gold said.

At Fekola, the company is currently weighing up an expansion that could see the life of mine could extend into 2030, including significant estimated increases in average annual gold production to over 550,000 oz/y during the five-year period 2020-2024 and over 400,000 oz/y over the life of mine (2019-2030).

Back in May 2018, B2Gold celebrated the official opening of the Otjikoto gold mine solar plant, in Namibia, one of the first fully autonomous hybrid plants in the world.

At the time, B2Gold said it would allow the company to significantly reduce fuel consumption and greenhouse gas emissions from the site’s current 24 MW HFO power plant. The shift to a HFO solar hybrid plant was, at that point, expected to reduce Otjikoto’s HFO consumption by around 2.3 million litres and reduce associated power generation fuel costs by approximately 10% in 2018.

In the company’s 2018 results, B2Gold said the plant was now providing close to 13% of the electricity consumed on site and the plant had achieved its expected HFO consumption and power generation fuel cost results.

B2Gold weighs up in-pit crushing and conveying as Fekola mine expansion economics stack up

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B2Gold’s plan to expand its Fekola gold mine, in Mali, by 1.5 Mt/y could see an up to $56 million investment in additional excavators, trucks, drills, support equipment and wheel loaders, according to the latest project economic study.

The expansion study preliminary economic analysis showed the company could increase throughput to 7.5 Mt/y, from the current 6 Mt/y base rate, by injecting just under $50 million over a period of some 18 months for processing expansion and upgrades.

As currently envisioned, the processing upgrade would focus on increased ball mill power, with upgrades to other components including a new cyclone classification system, pebble crushers, and additional leach capacity to support the higher throughput and increase operability.

“Critical path items include ball mill motors and the lime slaker, both of which will be commissioned in Q3 (September quarter) 2020,” B2Gold said.

“In parallel with the expansion, B2Gold is studying the addition of a solar power plant, which would reduce operating costs and greenhouse gas emissions. The current on-site power plant has sufficient capacity to support the expanded processing throughput, with or without the solar plant.”

On top of this, the company would need to invest in its mining fleet.

The current mining fleet consists of four Caterpillar 6020B excavators with haul trucks, drills, and support equipment to match, and mines an average of 36 Mt/y. The Whittle study results currently indicate mining production rates ranging from 54 Mt/y to 76 Mt/y are optimal to support the expanded processing rates over the life of mine and optimise head grade during the period 2020-2024.

B2Gold said: “Increased production will be achieved with the addition of two to four excavators with corresponding trucks, drills, and support equipment. Large front-end loaders would also be included to maintain fleet flexibility.

“Mine fleet expansion timing and scale will be optimised during Q2 (June quarter) 2019 and will generally be equipment loan/lease financed over a five-year period. The study has included $28 million for expansion to 54 Mt/y and an additional $28 million (for a total of $56 million) to go to 76 Mt/y.

“In parallel with the Whittle study, B2Gold is reviewing in-pit crushing and conveying as a means to reduce operating costs and potentially implement tailings and waste co-disposal at the Fekola mine.”

The expansion study estimated optimised that the life of mine could extend into 2030, including significant estimated increases in average annual gold production to over 550,000 oz/y during the five-year period 2020-2024 and over 400,000 oz/y over the life of mine (2019-2030).

This would see an increase in project net present value of approximately $500 million versus the comparable amounts in the company’s latest AIF mineral reserve life of mine model based on a $1,300/oz gold price and a discount rate of 5%.