Complex sentence: The port has an annual capacity of 80 million tonnes of iron ore, compare to 140 million tonnes annually at Dampier, the former being approximately 40% of Rio Tintos annual iron ore production from the Pilbara, as of 2009.
Split into simpler sentences: The port has an annual capacity to handle 80 million tonnes of iron ore, compare to 140 million tonnes teh port of Dampier can handle annually. The former is approximately 40% of Rio Tintos annual iron ore production from the Pilbara, as of 2009.