As the industry ponders ways to rely less on traditional power sources, Resolute Mining is already making great strides in developing an off-grid solution for its Syama Gold Mine in Mali. GERARD PETER writes.
Last year, ASX-listed Resolute signed a joint development agreement with South Africa’s Ignite Energy to develop a new 40 MW independent solar hybrid power plant at Syama.
The plant will combine solar, battery, and heavy fuel oil (HFO) technologies. When constructed, it will be the world’s largest off-grid, fully integrated hybrid power plant for a stand-alone mining operation. It is expected to be fully operational by the end of 2020.
Located in the south of Mali, Syama benefits from two fully operational, parallel sulphide and oxide processing plants with site production capable of more than 250 000 ozpa.
Ore for the 2.1 Mtpa sulphide circuit is currently sourced from open pit stockpiles while the A21 satellite pit supplies oxide ore to the newly constructed 1.3 Mtpa oxide circuit.
Over the past 30 years, Syama has produced more than 4 Moz of gold from open-pit mining. Resolute acquired the asset in 2003 from Randgold Resources (now Barrick) and placed it on care and maintenance.
The company’s positive definitive feasibility study, completed in June 2016, has extended mine life to at least 2028 and led to immediate development of the Syama underground mine.
Now, the company aims to make Syama the world’s first purpose-built, fully automated underground gold mine powered by the world’s largest hybrid power solution.
Taking operations off-grid
Historically, Syama operated on a 28 MW diesel fired power station. The power station was originally established by BHP in the 1980s and contains a fleet of diesel generators that have been progressively expanded to meet operational requirements.
Resolute has been examining opportunities to reduce the mine’s reliance on diesel, and reduce costs, for many years. The current cost to generate power ranges from $0.20 kWh to $0.24 kWh depending on prevailing diesel fuel prices.
Last year, Resolute conducted an international expression of interest tender process seeking proposals for an independent power producer (IPP) model, whereby a third party would be responsible for construction and operation of new power generation facilities.
Resolute also investigated, in parallel, an owner-operator model. This work, which accessed innovative energy progress being made across the mining industry in Africa, helped identify a new hybrid energy solution for Syama.
The new solution is to be funded and constructed under an IPP model whereby Ignite Energy, will be responsible for the design, construction, ownership, funding, and operation of the new solar hybrid power facility on an exclusive basis.
Ignite will supply power to Resolute on a guaranteed basis, subject to a maximum tariff over a term of between 12 and 20 years.
Project director, John Wheeler states that Resolute is currently finalising the power purchase agreement (PPA) with Ignite.
“The PPA is expected to be finalised in the first half of 2019, allowing for a staged development of the plant to commence in 2019 and be commissioned during 2020,” he explains.
The solution will comprise an advanced combination of modern solar photovoltaic generation (Solar PV), HFO-based generation and battery-based energy management system. HFO fuel costs can be up to 50% lower than diesel with larger modern generating units substantially more efficient than Resolute’s current engines.
The addition of a component of sustainable environmentally-friendly low cost power from solar PV, and the use of batteries to provide spinning reserve and manage loads more efficiently, is projected to result in a substantial reduction in Syama power costs.
Wheeler adds that the solar hybrid power plant presents the lowest cost of energy solution to the company.
“The solution allows us to draw power from three off-grid solutions. This will generate savings of up to 40% on the current operating costs of power.”
A cleaner African footprint
What's more, the replacement of Resolute’s existing diesel generated power plant will also provide significant environmental benefits. This includes lower carbon emissions solution, thereby providing tangible benefits to local Mali communities.
John Wellborn, MD and CEO of Resolute states that the company has been operating in Africa for 20 years and is proud of its legacy on the continent.
“The development of advanced, efficient and more environmentally-friendly power solutions is consistent with our broader intention to build and operate mines which utilise currently available advanced mature technologies, and which also anticipate and facilitate future developments and improvements.
“Lower cost self-generated power provides significant advantages for Syama, including the opportunity to provide social and economic benefits for the region.
Also, the addition of a new lower cost power solution is a key component in the reduction of life of mine all-in sustaining cost for the Syama underground gold mine to $746/oz,” he concludes.