IGO has been undertaking a strategic review in an attempt to revaluate its resources.
The world's largest producer of iron ore shipped 80.3 million tons of the steel-making commodity in the quarter.
Portugal already has the largest copper mine in the European Union, operated by Lundin Mining.
The solar farm could displace up to 11% of natural gas currently used for generation across Rio's integrated mining operations in the Pilbara.
