A Rio Tinto coal mine in the Hunter Valley. According to a separate leaked timeline prepared last July and obtained by Fairfax Media, the Baird government had planned to have "final sign-off" of the studies before next month's NSW elections but "unforeseen delays" had occurred. The results of the twin OEH draft reports – a Strategic Assessment Report on the Future Coal Mining in the Upper Hunter Valley and the Biodiversity Plan – are due for an "industry review" before being presented to cabinet, and later to the federal Environment Minister, Greg Hunt, the timeline shows. According to the biodiversity study, seven species including the regent honeyeater, diamond firetail and brush-tailed phascogale, face being wiped out in the region. Endangered communities at risk include the Hunter Valley Weeping Myall Woodland and the Warkworth Sands Woodland.

Little has been known of the progress of the studies into the biodiversity impacts of the mines since terms of reference were signed off by the former federal environment minister, Tony Burke, in October 2012. "We are frankly shocked that the Office of Environment and Heritage has been working behind the scenes with the coal industry on a plan for 16 mining projects that will potentially push threatened wildlife and ecological communities to extinction in this region," Georgina Woods, a spokeswoman for Lock the Gate, said. "The public has had no opportunity to see the results of this assessment and advocate for the protection of our endangered wildlife and bushland," Ms Woods said. "The agency responsible for protecting wildlife has utterly sold out the Hunter, giving privileged access to the very companies that want to mine the last remnants of bushland in this valley." A spokesman for the OEH said the current timetable was to make the reports public by the second half of this year.

"There has been extensive land clearing in the region for a variety of uses over the past 150 years and there is benefit in proactively identifying desired conservation outcomes in advance of project-by-project applications for future coal mining," the spokesman said. While the specific areas to be mined were yet to be determined by the miners, the assessment would help improve environmental outcomes and provide "greater certainty for the community, industry and government", the spokesman said. Environment Minister Rob Stokes said the government "is committed to a comprehensive independent assessment of the ecological sustainability of new development", with the UN's hierarchy convention of "avoid, minimise, offset" applied. "The intent of the strategic assessment is, in part, to identify species that are more vulnerable to loss of habitat," Mr Stokes said. "This will provide mining companies the opportunity to avoid impacts on sensitive areas, up front in the mine-planning process." Fairfax Media also sought comment from Opposition Leader Luke Foley.

'Death' blueprint The OEH study covered only part of the mining impacts from the planned projects. Other cumulative effects from the new mines would include impacts on water, air quality and noise levels. A report released this week by the Climate and Health Alliance said burning coal for electricity generation in the Hunter Valley was already causing health impacts costing hundreds of millions of dollars annually. Coal output in the region could increase from about 145 million tonnes a year now to 243 million tonnes by 2022, the report said. Greens mining spokesman Jeremy Buckingham said the coal mining plans amounts to "a blueprint for the death of the Hunter Valley and a climate suicide note".

"This plan will enable the continued destruction of the valley into a moonscape, by allowing companies to escape the specific requirement to account for threatened species and find and protect similar ecologies as offsets," Mr Buckingham said. "It's all about facilitating the coal industry and is a very dangerous move for threatened species and the remaining environment of the Hunter Valley," he said. Stephen Galilee, the chief executive of the NSW Minerals Council, said it was "impossible to comment" on the specifics of the reports because the working documents had not been provided to industry. "The purpose of identifying species at risk of extinction is to ensure that additional measures are put in place to protect them," Mr Galilee said.

The draft biodiversity report also raised doubts about the granting of offsets for future mine rehabilitation as compensation for ecosystem destruction. "[T]he capacity to predict change and measure self-sustainability of rehabilitation on mined land is limited ... This presents significant risks to government and to biodiversity conservation in NSW," the report notes. Phil Gibbons, an associate professor at the Australian National University and one of the architects of NSW's native vegetation laws, said the danger was further fragmentation of threatened ecosystems. "If you isolate a population, it becomes genetically inferior because it starts to inbreed," Professor Gibbons said. Fire, disease and future climate change would all add to undermining their resilience. Professor Gibbons also cautioned against the use of mine restoration as a form of offset to compensate for land being cleared.

"The success rate of restoration is between 20 and 50 per cent," he said. "A lot of impacts on natural systems can't be met through ecological restoration, at least for hundreds of years." Mr Galilee defended the use of biodiversity offsets planned for the Upper Hunter and other mining projects. "They provide environmental benefits to compensate for residual impacts that remain after avoidance and mitigation measures have been accounted for," he said. "Importantly, offsets do not make unacceptable impacts acceptable."