THE state's water watchdog is investigating if Whitehaven Coal is illegally building a pipeline to transfer groundwater from a farm to its Maules Creek mine.
The Natural Resources Access Regulator (NRAR) has received reports about potential breaches at Maules Creek pipeline and is investigating whether the mine obtained the relevant approvals.
"As this investigation is ongoing, we are unable to provide any further details at this time," an NRAR spokesperson said.
Along with the construction of the pipeline, there are questions regarding whether the mine has approval to access and use groundwater, if it can transfer the water from the farm in Zone 4 to the mine in Zone 5 and if it needs to carry out further environmental studies before doing so.
Whitehaven has already begun moving the groundwater via a large water carting operation, with up to two megalitres a day delivered from the farm to the mine.
"At the same time, work on accessing other supplementary long-term water supply sources for the mine continues," a Whitehaven spokesperson said.
"One of these supplementary sources is the construction of a pipeline from Whitehaven-owned bores.
"We are systematically progressing through applicable controls and approvals processes with relevant state and local government authorities so these measures can be fully implemented."
It's understood Narrabri Shire Council has approved roadworks for construct Whitehaven's water pipeline along Therribri Rd, however the company may need further approvals from the state government.
The use of groundwater was not mentioned in the mine's approval conditions - the three sources of water listed are run off, water recovered from mining operations including pit water and a high security water allocation from the Namoi River.
In 2015, Idemitsu's nearby Boggabri Coal mine was running short of water. It wanted move to groundwater, and was forced to submit a planning modification and multiple environmental studies.
However, a Department of Planning spokesperson said the two were not comparable, as Boggabri Coal sought to build a new borefield.
The pipeline investigation is NRAR's third in to Whitehaven's Maules Creek mine.
The watchdog has alleged the mine is taking more surface water than it's legally entitled to and is investigating a similar claim for groundwater, following reports from nearby farmers that their bores have run dry.