Complex sentence: The port was to connect with the existing channel which serviced Port Pirie and was considered to aid the shipping of copper ore from Mount Remarkable and Melrose in the Southern Flinders Ranges.
Split into simpler sentences: The port was to connect with the existing channel which serviced Port Pirie. It was considered for the possible conveyance of copper ore from Mount Remarkable and Melrose in the Southern Flinders Ranges.