Seabed Phosphate Mining at 400 Meters
Chatham Rock Phosphate Ltd
A well studied deposit of phosphate is present within New Zealand jurisdiction on the crest of the Chatham Rise, 240 nautical miles east of the South Island. An estimated 25 million tonnes of phosphate occurs as nodules 1 mm to 150 mm in size within a silt/sand layer generally less than 70 cm thick, overlying chalk. The phosphate is very good as direct application fertilizer or can be further processed. Chatham Rock Phosphate Ltd (CRP) has a licence over the richest part of the deposit and with Royal Boskalis Westminster of the Netherlands is carrying out full exploration and engineering design work. The plan is to commence mining in early 2015. A trailing suction cutter system developed for the 400m water depth will be used. The nature of the deposit and the engineering and mining design and challenges will be presented.