The environment department in Australia’s Queensland has launched an investigation into reports that Adani Enterprises drilled groundwater bores at the Carmichael coal mine without proper approval, ABC News reported on Wednesday.

Environmental group Coast and Country has obtained high resolution satellite and drone imagery that reportedly shows the illegal work at the site. “Adani have sunk six dewatering bores,” said group’s spokesperson Derec Davies. “They’ve drilled into Great Artesian Basin aquifers, they’ve put at risk our groundwater particularly at a time when half the country’s in drought.”

Adani Enterprises, however, claimed the groundwater bores were purely to take geological samples and monitor groundwater as allowed under their current stage one approval, reported The Australian. “Adani Mining is not dewatering for mining operations,” the company said in a statement. “Like all resources companies, we have ongoing dialogue with regulators about our operations and regularly submit information to them as required under our various approvals.”

An Adani spokesperson said the company had “not been notified of an investigation.”

A spokesperson of the environment department said the “bores were recently drilled and were not in place at the time of a recent inspection of the site” by departmental staff. “The department is now investigating the location and purpose of these bores,” the spokesperson added.

Environmental groups have raised concerns about the impact of groundwater bores at the Carmichael coal mine site on the Great Artesian Basin, which is the source of groundwater for large parts of the region. They fear that any “dewatering” bores, which lower groundwater levels to make mining activities easier, could have a devastating effect on the Doongmabulla Springs wetland area.