What is seabed mining?

Seabed mining is an experimental industrial field, which involves extracting submerged minerals and resources from the sea floor, either by dredging sand or lifting material in any other manner. Globally and in New Zealand, sand has been the primary target; primarily for use in construction but recently, for replenishment of urban beaches.

Mining sites of significance in New Zealand include the Kaipara Harbour (primarily for construction sand), and Pakiri Beach for concrete and the replenishment of Auckland’s beaches. These operations have been traditionally carried out in shallow depths (up to 25 metres), by suction dredges pumping sand onto barges.

The ironsands off the west coast of the North Island of New Zealand, are a unique geological and marine environment, currently in the crosshairs of global mining companies looking to exploit their high iron content and low extraction costs.

Initiatives to mine for minerals in much deeper waters have recently been unveiled in Papua New Guinea, and it appears this is the beginning of an era of sea floor exploration, as land reserves begin to diminish. Nearer to home, there are already companies looking at the feasibility of extracting phosphates from the Chatham Rise.

However much of the science around the environmental impacts of all these emerging ideas is incomplete and unproven. The common consequence of all types of operations is the obliteration of any marine life in the mined area and in surrounding areas due to the smothering effects of the plume created when unwanted matter is released back to the sea floor.