The footprint change is one of several modifications being proposed by the company ahead of submitting final environmental studies to the Environmental Protection Authority. Modifications also include increasing the proposed project output from 4.5mtpa to 4.7mtpa, whilst simultaneously reducing environmental impacts.
K+S Salt Managing Director Gerrit Gödecke said the project changes were the result of several years of studies and engineering work.
“We have worked very hard over several years to come up with a project which is both economically feasible, while minimising environmental impacts.”
The project changes to reduce environmental impacts include:
• Reduction in size of Development Envelopes.
• Reduction in support infrastructure and access road disturbance footprints.
• Reduction in pond footprint and inclusion of a bitterns dilution pond.
• Reduction of the seawater intake locations from two to one.
Some key changes are outlined below.
Development envelopes and project disturbance
Mr Gödecke said successfully making the Development Envelopes, and associated project disturbance areas, as small as possible was critical to minimising potential impacts.
“We needed to do this to fulfill our commitment to reducing environmental impacts where possible.”
The proposed Development Envelopes have been significantly reduced in size – to reduce impact on the environment and also maximise efficiency of salt production.
- Project Development Envelope – reduced from 67,570 ha to 10,211 ha (85% reduction).
- Road Development Envelope – reduced from 24,107 ha to 1,186 ha (95% reduction).
Within these envelopes, direct disturbance areas have also been reduced.
- Pond clearing areas from 15,000ha to 10,211ha (32%)
- Road disturbance footprint from 800ha to 160ha (80% reduction)
Mr Gödecke said the most pleasing aspect to the decrease in project footprint was the minimised disturbance to algal mats.
“While we have located Ashburton Salt as far as possible from environmentally significant mangroves and wetlands to the south, there will still be some algal mat disturbance.
“Our proposed changes have now reduced the pond related disturbance to algal mats from approximately 16ha to 8ha, or 50%.”
Reduction of creek intake areas from two to one
Solar salt production requires sea water to be pumped into salt ponds. Previously, two intake locations were proposed (Urala Creek North and South).
Now it is proposed that only one seawater intake at the deeper Urala Creek South is required. Selection of only one seawater intake (instead of two) will result in reduced disturbance.
Bitterns dilution pond
Bitterns are the left behind product after evaporation of seawater and removal of the crystallised salt. It contains no additives and consists of concentrated naturally occurring elements of seawater.
The Ashburton Salt project proposes returning this by-product back to the ocean in a carefully managed and monitored way – but before doing so, it will be diluted with seawater to reduce concentration, at approximately a 1:1 ratio.
A bitterns dilution pond was not previously included in project plans, however this is now being included as pre-diluting bitterns will even further reduce Marine Environmental Quality impacts and therefore impacts to subtidal Benthic Communities and Habitats and Marine Fauna.
Project output increase
While most of the proposed changes related to a decrease in size or impacts, Mr Gödecke was very pleased to also propose an increase in the projected salt output.
We are proposing a changed output of salt product (NaCl) from 4.5 MTPA to 4.7 MTPA, while achieving a decrease in pond footprint, no increase to seawater intake volume and no increase to pre-diluted bitterns volume or salt concentration.
“The production increase is from the revised salt production modelling which is good news for our project.”
These changes will be available in detail when the project’s Public Environmental Review document is released for public comment by the Environmental Protection Authority in June 2023.
