However, mine owner Whitehaven Coal says its use of water was legal, and that Lock the Gate either didn’t “understand how the framework operates or are deliberately distorting the truth”.

Lock the Gate spokesperson Carmel Flint says the group had data that showed mines like Maules Creek had not obtained licences for the huge amount of water they capture from run-off or rainfall.

“There is a legal cloud hanging over the water intake of the Maules Creek coal mine and other NSW coal mines,” Ms Flint said.

“We have referred this matter to the Natural Resources Access Regulator, which has agreed to investigate, because we believe that there are no valid legal grounds for the mining industry using billions of litres of water a year which it has no licence to take.

“We’re calling on Regional Water Minister, Niall Blair, to intervene urgently and get the industry under control.”

A spokesperson for Whitehaven said the mine was fully compliant with its use of water within its Water Access Licences and other applicable requirements under the Water Management Act.

“Using rainfall and surface runoff is permissible under the act and indeed is defined as best practice management,” they said.

“The idea mining companies are at fault for capturing and using surface water has no legal or even environmental legitimacy.

“The government’s own rules compel companies to capture and store rainfall and surface runoff and that using water in this way can drastically reduce reliance on other water sources, such as rivers.”

Lock the Gate says the Maules Creeks 2016 Annual Review shows the mine captured 1800 million litres of surface water in 2016, despite being licensed to only take 30 million litres.

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NSW Mining says the claims by the environmental group were “incorrect and misleading”.

“Lock the Gate have either not understood or are deliberately misrepresenting the legal framework,” the group said through a statement.

“Under most Environmental Protection Licence conditions mining operations are obliged to capture rainfall and surface runoff from mine operational areas, with limited allowable discharge opportunities.

“The use of locally collected runoff from mining areas by mining operations helps to minimise the amount of water mining operations need to extract from local waterways.”