Lock the Gate Alliance will use industry and publicly-available licensing figures to accuse mining companies of taking about 20,000 million litres of harvestable water per year more than they are licensed to, in a submission arguing much more needs to be done to protect Hunter water resources.

The 40,000 million litres of rainfall and run off surface water that was captured within mine land in 2016, and provided 55 per cent of the mining industry’s water use in that year, was nearly twice the volume of surface water licences the industry held across the Hunter River system, Lock the Gate will tell the Senate inquiry.

In June the NSW Natural Resources Access Regulator announced mining industries across a large part of NSW, including the Hunter, would be the focus of “targeted activities” covering water harvest rights.

A three month time frame “has been chosen to address the urgency for action on immediate and known compliance matters and to ensure environmental flows are successful”, the regulator said.

In NSW rural landholders including mining companies can build dams that capture 10 per cent of the average regional rainfall run-off. Higher volumes of water capture require licences.

A 2014 Lock the Gate investigation of Hunter surface water entitlements found the mining industry held 20,736 megalitres of surface water entitlements comprising 5324 megalitres in the unregulated river and 15,421 megalitres in the regulated river covering the Hunter River system.

In a submission to the Senate Lock the Gate said extensive open cut coal mining in the Hunter “continues to profoundly affect alluvial aquifers in the region and the draw down caused by these mines is also now known to be drawing from surface water as well”.

Mine pits are generally set back at least 150 metres from alluvium and river channels “but large volumes of water flow into the pits from the porous rock aquifer that comprises the coal seam”, Lock the Gate will tell the inquiry.

“The mining industry doesn’t have to pump a lot of water from the river because it captures rainfall run-off across its huge landholding and uses that water to run the mines,” Lock the Gate spokesperson Georgina Woods said.

“The industry’s own figures indicate this captured run-off makes up 55 per cent of the water used by the industry. Under NSW water law landholders are not allowed to catch all the water on their properties for free beyond a basic minimal right. The volume of water being taken in this manner by the coal mines in the Hunter goes for beyond that minimal right and requires licencing because that water is part of the water sharing plans that apply to all water users in the Hunter.”

The issue is particularly pressing during a time of drought, Ms Woods said.

In the Upper Hunter’s Goulburn River area property owner Julia Imrie, who is completing a doctorate on water impacts within the area, said open cut and longwall coal mining in the headwaters of the river at Ulan had been extracting increasing amounts of groundwater and intercepting rainfall runoff for many years.

Plans for more underground mining close to the Goulburn River put it at further risk, Ms Imrie said.

Lock the Gate has referred questions about the legality of rainfall and surface water collection at Maules Creek open cut coal mine to the Natural Resources Access Regulator after a similar investigation found a disparity between mining industry harvesting figures and water licences. 

The NSW Minerals Council has told the Senate that the mining industry is a “relatively small user of water” and used 1.5 per cent of total water consumed in the state in 2015-16, compared with 60 per cent used by agriculture and 11 per cent by households.

“Mines often recycle and use poorer quality water for purposes such as dust suppression, reducing the need to use higher quality water that can remain available for other users,” the Minerals Council said.

“Despite mining's relatively small water use in NSW, mining’s impacts and use of water is highly regulated by a number of robust water laws starting from the early stage of project planning through to post mine closure.”

The Minerals Council argued against any further regulation of water use, saying “adding further layers of regulation is unnecessary and would not materially improve the protection of water resources in NSW”.

“The regulatory regime surrounding the extractive industry’s water use is comprehensive and stringent. We are not aware of another industry which is more highly regulated than the current regulatory regime for water use in the extractive industry.

“Miners spend a significant amount of time and financial resources in ensuring water law requirements are met.”

The industry anticipated that establishment of the Natural Resources Access Regulator in 2017 would lead to an increase in water monitoring and auditing activities.