Chatham Rock Phosphate Ltd holds an exploration licence over an area off the coast of New Zealand believed to have significant seabed deposits of rock phosphate and other potentially valuable minerals.
The licence area of 4,726 square kilometres is 450 km east of Christchurch, at shallow depths on the Chatham Rise and in New Zealand territory.
Extraction of the rock phosphate could provide a locally produced alternative to the 1 million tonnes of this material annually used in New Zealand and primarily imported from Morocco, thereby reducing our carbon footprint as well as high transport and foreign exchange costs.
Rock phosphate is an essential ingredient of manufactured fertiliser and can be applied directly to pasture with less environmental damage than super- phosphate from run-off. Extensive exploration in the 1970s and 1980s identified the potential for a 100-year supply for the New Zealand market. Recent substantial increases in the market value of rock phosphate and advances in offshore extraction technology mean it is now feasible to harvest this resource. The deposits are comprised of nodules lying on the seabed at relatively shallow depths and the relevant technological components for such extraction is used routinely.
Our work has focussed on compiling and consolidating existing information and data pertaining to the Chatham Rise phosphate deposit and related marine environment, as well as acquiring additional data to fill in any information gaps. Activities in our work programme include the following:
This work has successfully identified areas of data and information deficiencies. These are the focus of ongoing investigations in 2012 and beyond. Activities included in the planned work programme for 2012 include the following:
- Detailed bathymetric surveying;
- Sub-bottom profiling;
- Sound velocity measurements;
- Box coring;
- Cone Penetration Testing (CPT);
- Sampling for the study of benthic fauna;
- Sampling for beneficiation studies;
- Sampling to assess phosphate deposit and geochemical characteristics;
- Sampling to assess the dredging parameters of the nodule hosting layer;
- The collection of still photography and video footage;
- Oceanographic current sampling;
- Environmental monitoring and data acquisition.
- Chatham Rock Phosphate holds 100% of the 4,726 square kilometre permit area (MPL 50270). A report by DJ Cullen of the NZ Oceanographic institute published in 1987 estimated the area could contain 100 million tonnes of rock phosphate. Preliminary studies indicate the rock phosphate can be extracted using existing technology for much less than the cost of buying and importing it from Morocco.
- Successful extraction could result in a much reduced carbon footprint from the New Zealand fertiliser industry as all imported rock phosphate is presently shipped from the other side of the world.
- Sourcing this resource locally would significantly improve New Zealand’s balance of payments by reducing imports.
- Chatham Rise rock phosphate may be more environmentally friendly as a fertiliser where it is applied directly to pasture with previous Government studies indicating less subsequent run-off.
- Chatham Rock Phosphate has the resources and potential fund-raising ability to finance the work programme to define the resource and complete financial feasibility.
- Extraction of the resource would be conducted in accordance with the environmental guidelines published by the International Marine Minerals Society “Code for Environmental Management of Marine Mining”.
The deposit, formed 7 to 12 million years ago, was discovered by New Zealand scientists in 1952 and extensively explored during the 1970s and 1980s by a range of private and public sector scientists. An estimated $70 million in current dollar terms was spent on at least 7 different voyages, each involving several weeks.
The data collected means the deposit is now very well defined. The best-sampled area of 380 square kilometres has an identified resource of 25 million tonnes.
The price over the past couple of years has recovered steadily to around $US150-US200 per tonne range.
Over the 30 years since the last serious exploration, extraction techniques have improved radically and it is expected extraction costs are expected to be substantially lower than the comparative cost of buying and shipping rock phosphate from the other side of the world.
Mineral extraction and construction is now routine in shallow seas. Even in the 1970s manganese nodules were being mined at depths 10 times greater than envisaged on the Chatham Rise. Nautilus Mining has estimated hard rock mining costs of $US50 to $US65 a tonne at depths of 2,000 metres and North Island iron sands are expected to be extracted from offshore deposits (at shallower depths) for $US4 to $US15 a tonne.