EPA officials said a partial collapse at the Warkworth mine occurred January 6, and was reported to the agency by mine officials. While the company reported at the time that the environment was not in danger and it had not caused the event, the EPA still ordered an incident report.

Warkworth officials also advised the EPA that it had already worked on sediment water containment; however, the EPA said, photos provided to investigators show that water is still leaking and some sediment from the original incident is not yet cleaned up.

“The EPA has requested additional information from Warkworth and will be conducting a site inspection to assess the impact,” officials said January 15. “Depending on the outcome of the investigation, the EPA will consider further regulatory action.”

It also has directed the mine’s owner, Rio Tinto, to commence cleanup to prevent further sediment leakage.

The spill is reportedly the third in the region in recent weeks; the EPA is also investigating a partial dam wall collapse at Peabody Energy’s Wambo operation following a mine collapse.

Regional media has also reported on a mine dam overflow at Rio Tinto’s Bengalla mine, though the EPA has not yet confirmed the nature of that incident.