The 22 ha solar photovoltaic plant at gold producer Iamgold's Essakane mine, in Burkina Faso, produces 25 000 MWh/y of electricity, while also reducing carbon dioxide equivalent emissions by 16.5 t, eliminating 5.5-million litres of fuel use a year and 120 fuel delivery trucks a year to sustain the mine's 400 000 oz/y of production, Essakane GM Mohamed Ourriban says.
"The inflation in logistics costs has added another advantage arising from our use of clean, renewable energy on site," he notes.
The mine doubled its capacity to process hard rock from 5.4-million tonnes a year by adding a second line to increase capacity to 10.8-million tonnes a year in 2013. A small adjustment commissioned in March 2021 increased this to 11.7-million tonnes a year.
The mine had three-million ounces in reserves in 2020, and was aiming for average production of 400 000 oz/y. It produced 412 000 oz of gold in 2021, he highlights.
The company's hybrid solar and heavy-fuel-oil power plant produces the 42 MW of power the site needs, and has also expanded as capacity has increased. The solar system has a 2 MW capacity, comprises 128 000 modules and was commissioned in 2018.
The use of the solar plant enables the company to switch off one of its heavy-fuel oil generators, although it must maintain solar production above 80% to prevent blackouts on site when doing so, said Ourriban.
He pointed out that the mine also had to grapple with cleaning dust off the solar plant and started out with manual cleaning and then mechanised the process and have now mounted the water and brush system on a tractor to maintain the solar plant's performance.
Additionally, the mine can potentially prevent blackouts when its solar plant production drops below 80% through the use of battery energy storage. It may do so in future, which would enable it to switch off two fuel generators when conditions are suitable.
"Given the cost of our current four heavy-fuel-oil plants, this has been an interesting project for us. We are thinking about adding energy storage capacity, which has many advantages, and we have many additional projects to pursue to reduce our energy consumption," he adds.
For example, the mine is looking at energy distribution and energy balance on site to increase the use of solar power, and thereby offsetting the need to use power from the heavy-fuel-oil generators that are 43% efficient.
"We are pursuing incremental projects, and have a continuous pipeline of optimisations to operations to reduce energy consumption and improve efficiency. We have achieved some and have a lot to pursue in future. Essakane has also allowed us to explore the use of renewable energy.
"We are also exploring liquefied natural gas (LNG) as a fuel source, but, given the short life of mine, we are not yet prepared to say we will integrate LNG. However, our work is providing Iamgold with valuable experience that can be used on projects and other operations in the future," said Ourriban.