Date | Jun 15, 2015: Mining for minerals such as copper could become more efficient and cause fewer environmental problems if miners look for their minerals at the bottom of the ocean rather than on land, according to a study—but some scientists say deep-sea mining may have harmful consequences that we still do not fully understand.

Source: Nautilus Minerals
Underwater operations by Nautilus Minerals

Nautilus Minerals is a company based in Australia and listed on the Toronto Stock Exchange that wants to harvest copper from the hot vents at the bottom of the ocean that spew sulfur and other minerals rising from the earth's mantle—the layer of earth directly below the planet's crust. The company commissioned Tacoma, Washington-based consultancy Earth Economics to compare the environmental impacts of their own mining methods with land-based mining operations now in use around the world.

Nautilus is in its construction phase and plans to begin production off the coast of Papua New Guinea at a site called Solwara 1 in the first quarter of 2018.

The report says demand for copper, one of the most commonly used metals on earth, will continue to climb, with everything from infrastructure to medical technology and electronics requiring the metal.

Executives from Nautilus are also betting that existing, terrestrial sources of copper are becoming scarce and more socially and environmentally dangerous to mine, but that the seafloor holds abundant reserves of copper and other minerals.

"I think it is important to apply the precautionary principle here. And if you don't know very much about the potential effects on an ecosystem, you have to sort of assume the worst."
-Craig Smith, professor of oceanography, University of Hawaii, Manoa

"We double the amount of copper we use every 10 years or so. The global market uses 20 million tons now, we will need 40 million tons in 2030. The question is: Where is that going to come from?" said Mike Johnston, CEO of Nautilus.

Nautilus' proposed operation would be unique among mining companies. The area it wants to mine is a patch of ocean floor roughly 1,600 meters below the ocean surface. The company is building a ship that hosts an on-board refinery and a control center where crew members operate giant machinery that cuts the rock around the vents. Rock and seawater are then pumped up to the ship, where the copper is processed and then sent to factories on land for further manufacture.

Earth Economics compared the potential effects of the Papua New Guinea site with three major land-based mines around the world—one each in Utah, Australia and Ecuador.

The Earth Economics report concludes that mining on the ocean floor would have little impact on the environment or on people, compared with the copper mines the group studied on land.

Terrestrial mining companies flush massive amounts of freshwater to collect the mineral-rich dirt and rock in mines, which are then filtered back out as minerals are extracted. Because they use salt water instead, a deep-sea mining operation would not waste valuable freshwater.

And deep sea mines would not displace communities that might be living on rich deposits or near processing facilities, the report said.

"With few exceptions, people inhabit or directly use the landscapes where copper mines are established," the report said. "There is a long history of conflict between mine operators and people living within, around and downstream of copper mines, tailings and smelter sites."

(Source: http://www.cnbc.com/)