THE Hunter's newest coal mine rated a severe or prolonged drought an "unlikely" risk to its rehabilitation work even as severe drought affected its rehabilitation and revegetation efforts, a critical audit of its first 18 months of operations has shown.
A mining operations plan lodged by MACH Energy's Mount Pleasant coal mine said the risk of such a drought leading to "widespread failure" of its rehabilitation work "was given a likelihood rating of 'D, unlikely'," a NSW Resources Regulator audit report prepared in August found.
"Given that the Hunter Valley region has been in a severe drought for the past two years, and MACH Energy staff advised that it has affected the rehabilitation and revegetation success, the risk ranking does not reflect the conditions," the regulator said.
"The observations made by the audit team on site do not give confidence that the titleholder has a good understanding of the risks to successful rehabilitation outcomes."
The critical audit occurred more than a year after the Department of Planning's division of resources and geoscience in February, 2018 amended mining lease conditions at Mount Pleasant so that the mine is no longer required to complete an annual compliance report. The change means the mine is responsible for notifying the regulator when it breaches any approval conditions.
Inspections by the Resources Regulator in May for the audit showed there were "several areas of significant erosion" across the mine site 2.5 kilometres from Muswellbrook, which was sold by Rio Tinto to MACH Energy in 2016. In 2018 it was approved to mine 10 million tonnes of coal per year until 2026. The mine was first approved in 1999 but no mining occurred until after the MACH Energy sale.
The Resources Regulator audit found the mine's rehabilitation assessment processes were flawed and "it would be easy for issues to be overlooked".
Where rehabilitation issues were identified by the mine during inspections, there was "no process to capture these issues, allocate corrective action tasks, track progress and close out those issues". "Where issues were identified, they remain only on the inspection checklist," the regulator found.
It also found the company's spreadsheet-based compliance register did not provide a mechanism for the mine to track compliance obligations against its conditions of consent.
Despite several areas of significant erosion across the site the issue of erosion was not included in the mining operations plan's risk assessment. The only reference to erosion concerns related to major storm events which the mine assessed as "unlikely".
There were no erosion controls on a topsoil stockpile with "quite a long slope length", the regulator's inspectors found.
"Given the potentially dispersive nature of the soils, the erosion risk was not adequately considered and, consequently, adequate controls were not identified and implemented."
MACH Energy advised the regulator its rehabilitation monitoring program was not implemented because it was waiting for a new rehabilitation strategy to be approved. But the regulator said failure to comply with a mining operations plan was an offence under the Mining Act.
The Resources Regulator found two non-compliances, made three observations of concern and two suggestions for improvement.
In a response to the regulator MACH Energy said an updated risk assessment incorporated risks of drought and other natural events on rehabilitation, but reiterated its view that "severe and/or prolonged drought in a mild to warm temperate zone such as the Hunter Valley is considered unlikely, despite the current drought conditions".
It outlined improvements to its processes and operations to address the issues raised by the regulator, but said the the audit report "relates to a number of brief observations during the May 2019 inspection, and is merely a snapshot of mine rehabilitation success over the full life-of-mine cycle".
Muswellbrook mayor Martin Rush, whose council raised serious air quality concerns because of the mine's close proximity to the town centre, said Mount Pleasant was approved with a "best practice rehabilitation condition which is more challenging than past practices".
"But clearly it has lessons to learn from mines like Mangoola when it comes to implementing the rehabilitation plan," Mr Rush said.
"The erosion and scouring and the absence of early native revegetation has not been good enough," he said.
"Council would expect that on its next visit to the site considerably more resources will have been deployed to ensure the mine is meeting its rehabilitation obligations."
Lock the Gate spokesperson Georgina Woods said it was unacceptable that the Hunter's newest coal mine was already "running into trouble with basic compliance with its environmental responsibilities".
"The industry should be operating at the highest standard as a basic mark of respect to the people and communities of the Hunter," Ms Woods said.
"It's extraordinary that MACH Energy rated severe or prolonged drought and erosion as 'unlikely' risks for the mine. It shows a shocking disconnect from the environmental constraints and challenges being experienced in the Hunter region right now."
The Resources Regulator also released topsoil management audits for Wambo, Hunter Valley Operations and Mount Owen coal mines, which identified some rehabilitation concerns at each mine.
The audit reports were published after a Resources Regulator report in June found six Hunter mines failed to comply with rehabilitation conditions.