As the controversial New Acland Mine near Toowoomba continues shedding 150 of its workers, an expert report commissioned by a group of landholders has raised questions about the coal mine's impact on groundwater.

Key points: Queensland's DNRME report in 2017 found aquifers near Kulpi were not directly connected to those near the New Acland Mine

Queensland's DNRME report in 2017 found aquifers near Kulpi were not directly connected to those near the New Acland Mine A new review says it has found gaps in the data and analysis used in the 2017 report

A new review says it has found gaps in the data and analysis used in the 2017 report A hydrologist who reviewed both reports has backed the departmental report and said groundwater decline could be due to drought and agricultural use

In 2017, in response to farmers' concerns of water level declines in bores around Kulpi, north of Toowoomba, Queensland's Department of Natural Resources Mines and Energy (DNRME) undertook a review.

It found that the basalt aquifers in the area were not directly connected to those near the mine.

It also confirmed that the deeper Marburg Sandstone, the other aquifer used by farmers, was at least 75 metres below the mining pit floor.

But a report by RMIT hydrogeologist Associate Professor Matthew Currell has found gaps in the data and analysis used in that study.

His report said there was a lack of detail about landholders' bores, such as depths and yields.

There is concern among many farmers in the Kulpi area about what has caused a string of water bores to drop or dry up. ( ABC Southern Queensland: Nathan Morris )

It also said there was "a significant gap in coverage of the monitoring network", particularly between the area where historic groundwater extraction has taken place, and the affected landholder's bores.

"The coverage of monitoring bores is not comprehensive enough to have detected any propagating drawdown influence related to the mine site water extraction," Associate Professor Currell said.

The proposed expansion of the New Acland Mine has divided local communities where the mine is a major employer. ( ABC Southern Queensland: Nathan Morris )

The report also said that the effects of historic water extraction can be delayed, and "such a scenario can't be ruled out in this case without more detailed mapping".

Seismic faulting in the area was another factor that Associate Professor Currell said was not adequately considered by the 2017 DNRME report.

Groundwater systems 'not connected'

But Queensland groundwater expert Clem Hill, who examined both reports, said that the basalt aquifers post-date the faulting in the underlying sediments.

"There's no major regional faulting that is acting as a conduit, so there no preferred pathways or streams of groundwater through that area," Mr Hill said.

A hydrogeologist in Queensland for over 30 years, Clem Hill says drought and overuse of groundwater could be the reason bore levels have dropped near Kulpi. ( ABC Southern Queensland: Nathan Morris )

Mr Hill also said there was actually a department monitoring well in the area in question that exhibited the same drawdown and recharge characteristics presented in the 2017 DNRME report.

Chief operations officer of the New Hope Group which owns the New Acland Mine, Andrew Boyd, said he stood by the findings in the 2017 departmental report.

"It should be noted that the New Acland Mine has been operational for over 17 years and during that time no landholder has gone without water due to the mine," Mr Boyd said.

The coal being mined at Acland is in the Walloon Coal Measures, a low quality water-bearing formation that hydrogeologist Clem Hill said is not connected to the groundwater systems that farmers used.

Steve and Des Kajewski had to drill this new bore after the one next to it ran dry in 2015. ( ABC Southern Queensland: Nathan Morris )

Mr Hill said localised factors could explain why bore water levels have declined.

"Obviously drought is one. [Another is] overuse of the water in the basalt aquifers because they're not an unlimited supply, they're only locally recharged, they're a local groundwater system," Mr Hill said.

"So if you're not getting a lot of rain in that area then you're not getting a lot of recharge. Therefore there's not a lot of sustainable water to be used in that area."

Irrigation systems like this are regulated through water licenses, but stock and domestic bores are not. ( ABC Southern Queensland: Nathan Morris )

Groundwater drawn for intensive agriculture like feedlots and dairies are regulated through water licences, but bores for stock and domestic use are not.

"There could also be some drawdown effect from intensive water use from other agricultural water users in the area around those basalts who are taking water from the Marburg formation," Mr Hill said.

He said there could always be more monitoring to improve groundwater management.

"There's a responsibility on landholders to understand what their own bores are doing. A stock and domestic bore may not even be put on the groundwater database," he said.

Where is the water going?

Meanwhile, farmers in the Kulpi area say there have been seven bores in the valley near Mt Darry that have dropped by up to 80 per cent, two have gone dry, and another two have dropped by 20 metres.

Desley Spies says seven bores in the valley have dropped by about 80 per cent and two have run dry. ( ABC Southern Queensland: Nathan Morris )

"If it was only one bore you'd say that's just nature, but [we need answers] when you get a line of bores down one valley that go, and they all drop back within a week or 10 days of each other," said Desley Spies, who comes from a family of settlers in the area.

"We don't know where it's going. It could be going to the mine," said Mt Darry farmer Michael Klein.

"We can't blame the mine one hundred per cent, we can't blame other irrigators, we can't blame other neighbours one hundred per cent. What we need to know and we need to know now [is] where it is going."

Michael Klein says farmers in the area simply want answers to where groundwater is going. ( ABC Southern Queensland: Nathan Morris )

The New Acland Mine is a major employer in the region and has been waiting 12 years for the approval of its stage three expansion.

The delay has seen New Hope Group make 150 of the mine's workforce redundant.

The Court of Appeal is still yet to hand down final orders on an appeal by the Oakey Coal Action Alliance against the environmental approval for stage three, and the Queensland Government still has not approved the associated water licence.

"We have a massive concern for the jobs, we really do. But I think we have to leave something in this country for the next generation," Ms Spies said.

The DNRME were contacted for comment, but said they could not respond while the 2017 report was part of court proceedings.