24 November 2016
Chatham describes how the use of RPR will improve water quality in NZ
OVERSEER is a software tool widely used by New Zealand farmers and their advisors to tailor fertiliser use to optimise
farm production while minimising environmental impacts.
Developed originally by AgResearch, it’s now jointly owned with the Ministry of Primary Industries and the Fertiliser
Association. An independent organisation, Overseer Ltd, has been licensed to use the OVERSEER IP to create a sustainable
business that delivers OVERSEER to users.
Recently the software application was upgraded and the latest version 6.2.3 was used to compare various farming
scenarios to assess what impact changing the type of phosphate fertiliser used has on the amount of P loss to water. In
all scenarios evaluated the use of RPR resulted in less phosphate loss to water than would be the case with soluble
phosphate fertilisers such as Superphosphate.
When OVERSEER was used to compare various farming scenarios the P loss was on average 18% lower when RPR fertiliser was
used compared to using Superphosphate. According to independent studies, changed farming practices resulting from using
RPR over an extended period could result in up to 80% less phosphate run-off.
This advance provides more evidence for farmers and their advisors that RPR offers a more environmentally friendly
source of phosphorus to New Zealand farmers. Over time this should result in increased use of RPR as it is substituted
for superphosphate and other phosphate fertilisers.
This is very relevant to Chatham Rock Phosphate because our rock phosphate is a particularly effective form of reactive
rock phosphate, demonstrated by extensive field trials undertaken in the mid-1980s and reinforced by recent tests.
As well as representing a secure local source, Chatham Rise-sourced RPR contains ultra-low levels of cadmium levels and
creates far fewer carbon emissions, so has a much lower carbon footprint than current northern hemisphere supplies.
As the Chatham Rise deposit will likely not be mined until 2020, we have identified several overseas sources of RPR and
can import this rock on request. We are already working with a private New Zealand-based fertiliser company to satisfy
the existing demand for reasonably priced material.
About Chatham Rock Phosphate
Chatham Rock Phosphate, a publicly listed company, was granted a mining permit in 2013 to develop New Zealand’s only
significant source of environmentally friendly pastoral phosphate fertiliser and is now preparing for a revised
environmental consent application.
Our role as custodian of this resource is focused on delivering a secure and sustainable local supply of low-cadmium
phosphate that will reduce fertiliser run-off into waterways, produce healthier soils and shrink fertiliser needs over
The resource has an estimated worth of $5 to $7 billion, representing one of New Zealand’s most valuable mineral assets
and is of huge strategic significance because phosphate is essential to maintain New Zealand’s high agricultural
productivity. Local and international investors have contributed more than $40 million to develop the project’s
financial viability, environmental benefits and impacts, technical and logistical requirements, local and international
We propose to extract up to 1 million tonnes of phosphate nodules from the top half metre of sand on identified parts of
an 820m2 area on the Chatham Rise, 450km off the west coast of New Zealand, in waters of 400m. Our environmental
consenting process has established extraction would have no material impact on fishing yields or profitability, marine
mammals or seabirds.
In progressing plans to submit a new application we are working with government officials to seek improvement in the
permitting process and iwi, academic, industry and central government input to ensure New Zealand can benefit from an
environmentally superior phosphate source.
Progress is continuing to achieve a Toronto Stock Exchange listing, to provide a more useful share-trading platform for
overseas shareholders and facilitate the capital raising needed for the consenting process and beyond.
We are also seeking to own other sustainable rock phosphate sources, to move from being a single project company and
take more control of our destiny.