News Analysis: Seafloor Mining in Papua New Guinea Area is rich in Copper, Gold, Silver, and Zinc Deposits. Since existing Robotic Mining Equipment is available, extraction of Seabed Deposits should be easily attainable. Once extracted, and sent to a recovery ship, the metals can then be sent to China for Smelting.
The extraction of Metallic Nodules in the oceans of the world is quite pervasive. Even so, locating rich deposits in shallower waters is economically most favored by Investors.
Reference: http://www.onepng.com/2013/10/seafloor-mining-robots-and-equipment.html