Complex sentence: The Cumbarjuem Canal, which links both rivers, has made the interiors of the Mandovi accessible to ships which ferry iron ore, Goa's prime mineral, mined in the eastern hills.
Split into simpler sentences: The Cumbarjuem Canal, which links both rivers, has made the interiors of the Mandovi accessible to ships carrying iron ore. Iron ore is Goa's prime mineral and it is mined in the eastern hills.