Australian miner BHP, the world’s largest mining company, struck a deal with Canadian mining investment group Mundoro to explore copper in Serbia. BHP has been looking to expand copper operations and find new deposits to boost supply of the metal essential for energy transition technologies. World’s top miners have been bullish on the outlook for copper, which is key in many clean energy technologies, including electric vehicles, wind turbines and grids. As the demand for copper expected to surpass supply, concerns over future shortages have been increasing.

BHP last month agreed to acquire Australian copper producer OZ Minerals for around $6.4 billion, marking its biggest deal in years. Its rival Rio Tinto also took full control over copper miner Turquoise Hill Resources in a $3.1 billion deal.

Now, BHP has agreed to pay fees and exploration costs for three copper exploration targets in Serbia with Canada’s Mundoro Capital. The deal ultimately allows BHP to take full control of any or all of the assets, should they find enough copper to justify building a mine.

Rio Tinto is already operating in Serbia, with an aim to develop a huge lithium mine. Those plans however were derailed a year ago when environmental and opposition groups protested over pollution risks, which forced the Serbian government to stop development.

Serbia’s president Vucic last week said he may review the decision to block the project.

BHP has said building its copper and nickel business is a key priority as it looks to balance its portfolio away from fossil fuels and ultimately iron ore. The company has already built stakes in a copper explorer in Ecuador and a nickel company in Tanzania.