WA's water regulator is probing South32's impacts on neighbouring farmland
Russell Reynolds blames South32's nearby mining operations for rising salinity levels in his dams. (ABC South West: Jon Daly)
In short:
Unusual changes to salinity levels and water flows have been observed on farms beside South32's Worsley mine.
One neighbouring property owner claims the miner is breaching its environmental conditions because of the water issues on his property.
What's next?
WA's environmental regulator is investigating the claims, but has not yet delivered a finding.
Drastic changes in salinity levels and water flows are being reported at farms neighbouring South32's Worsley bauxite mine in Western Australia.
In recent years, some properties have gone dry, while others have had rapid rises in groundwater levels, causing waterlogging and degradation of land.
Some residents attribute the hydrological changes to South32's nearby mining operations.
Russell Reynolds's farming property sits between the Mount Saddleback mining area and the Hotham River, near Boddington, 130 kilometres south of Perth.
He said his spring-fed dam was almost undrinkable because of rising salinity.
Mr Reynolds also claims a surface stream that once ran each winter has been dry now for two years.
"It's a bit disappointing, because they've made no effort whatsoever about controlling water flow so we still get enough water,"Mr Reynolds said.
The Department of Water and Environmental Regulation (DWER) confirmed it was currently investigating Mr Reynolds's claims.
"DWER has kept Mr Reynolds informed throughout the investigation, which may take several months to complete due to its hydrogeological complexity," a spokesperson said.
South32 has approval to take 900 million litres of groundwater a year, most of which is used for dust suppression. (ABC South West: Jon Daly)
Miner draws millions of litres
In February this year, South32 received state and federal approval to increase its groundwater use from 500 million litres to 900 million litres a year, primarily for dust suppression on haulage roads.
"It'll only get worse," Mr Reynolds said.
"If you haven't got enough water to mine that size area, you shouldn't be allowed to mine that size area."
Mr Reynolds blames his water issues on a series of major production bores, known as the Tunnell Road borefield.
Russell Reynolds says the seasonal surface water stream on his property has run dry for two years. (ABC South West: Jon Daly)
The borefield draws water from an underground stream that runs through the Saddleback Timber Reserve and onto Mr Reynolds's property, filling his dams.
In 1996, the borefield supplied 85 per cent of water for the mine, with an average of 465,000 litres of water being extracted every day.
From December last year to June this year, South32 drew an average of 665,000 litres per day from Tunnell Road bores, with eight trigger-level exceedences, according to a recent compliance report.
The report noted dryer-than-average rainfall contributed to higher monthly water demand, but overall water usage from the borefield remained below recommended yield.
"Basically, they're taking it before it can get to the property,"Mr Reynolds said.
"To me, that bore system should be restricted."
Russell Reynolds says the water issues on his farm constitute a breach of South32's environmental approval conditions. (ABC South West: Jon Daly)
Rising salinity levels
He said the reduced groundwater flow was also to blame for a 500 per cent increase in salinity levels of his spring-fed dam.
He claims the dam's total dissolved solids (TDS) level jumped from 180 milligrams per litre (mg/L) in 2014 to 1,100mg/L in 2025.
However, the ABC was unable to verify the original 2014 test results.
Anything above 1,200 mg/L is considered unacceptable for drinking, according to national drinking water guidelines.
Russell Reynolds said the regulator needed to step up and hold the mining company to account. (ABC South West: Jon Daly)
In 2020, South32 commissioned a report on ground and surface water as part of the expansion proposal approved earlier this year.
The report shows higher salinity levels in the Tunnell Road borefield, with average TDS levels ranging from 163–1,510 mg/L, compared to 160–391mg/L measured in a 1995 submission to the Environmental Protection Authority (EPA).
"Right at the moment, they don't have anything to control salt level, and they know exactly what's happening," Mr Reynolds said.
South32 issued a brief statement noting it was aware of the "matters that have been raised" but did not respond directly to the ABC's questions.
"Worsley Alumina manages and monitors groundwater usage, quality, levels and its response in accordance with its approved Water Management Plan," a South32 spokesperson said.
A line of dead native trees marks the water course that appeared on one farm in a matter of years. (ABC South West: Jon Daly)
Mining and water mounding
Other farming properties beside the Mount Saddleback mining area have had sharp increases in groundwater levels and flow.
The ABC visited a property with a surface water stream that had appeared out of the adjacent forest within the last four years.
The stream's course through the farm is marked by a cluster of dead jarrah trees, and it has white salt scald beside it.
The ABC has seen evidence of salinity levels in dams increasing by more than 100 per cent in four years on other nearby farming properties.
Ann Choong, a trained lawyer and member of the environmental group Dwellingup Discovery Forest Defenders, believes the changes are a result of water mounding, which occurs when forest is cleared, and cap rock is removed.
Satellite images from 2015 and 2025 show the changes in surface water flow on a farming property beside Mt Saddleback. (ABC South West: Jon Daly)
Water mounding occurs when more groundwater flows downhill, increasing the water table and salinity in low-lying areas.
South32's Water Management Plan identifies water mounding as a potential impact of its operations, noting the risk of increases in salinity in groundwater and changes in surface water flows associated with changes in land use and land form.
"These impacts are interconnected and have a limited duration associated with the temporary change in land use during mining activities," the management plan states.
"Groundwater levels typically return to those equivalent to the unmined situation within five to 20 years."
South32 says it manages and monitors groundwater usage in accordance with its approved management plan. (ABC South West: Jon Daly)
Breach of 'no adverse impact' condition
Dr Choong has been working to bring the concerns of the few neighbouring landholders to the attention of the regulator.
She said many farmers had already sold their properties to the mining company.
"There aren't a lot of people to speak up about what happens to the land,"she said.
"In 20–40 years, the ore will run out, and the question is, what are we going to have in terms of farmland?" she asked.
South32's 2020 groundwater study concluded declining rainfall was primarily responsible for rising salinity, not bauxite mining.
Ann Choong has been helping landowners raise their water concerns with the regulator. (ABC South West: Jon Daly)
"Bauxite mining in the Saddleback area does not appear to be causing any additional observable salinity increase over and above that recognised as background response to regional rainfall decline," the report stated.
Mr Reynolds argues his experience challenges that finding, and the impact on his property constitutes a breach of environmental conditions set on South32's Worsley mine expansion.
"The emphasis is on DWER. How about [you] start acting on what you've put in place?" Mr Reynolds said.
As a condition of South32's expansion last year, the state government said there had to be "no adverse impacts to neighbouring groundwater users as a result of the proposal".
"At this stage, DWER has not yet determined whether any adverse impacts have occurred," a DWER spokesperson said.