When filled with water, the Hazelwood mine will be half the capacity of the Thomson Dam, with the former mine-turned-lake’s deepest point expected to be 105 metres, according to site owner ENGIE.
ENGIE mine technical services manager James Faithful told The Express rehabilitation works were ahead of schedule during a tour of the site on Thursday.
“What a lot of people don’t actually realise is the area underneath the Morwell township essentially and the Princes Freeway has been rehabilitated,” Mr Faithful said.
“You can get a really good perspective inside the mine because you can see the coal batters and what they were pre-rehabilitation and what they do look like after rehabilitation.”
Part of the rehabilitation work is to decrease the incline of the mine’s batters back to a more manageable angle, allowing maintenance work to be carried out around the perimeter of the of mine.
Mr Faithful said batters pre-rehabilitation stood between 50 and 60 degrees but post rehabilitation the slopes would be between 15 and 18 degrees.
“That’ll be flat enough so you can plant on it and do maintenance like grass slashing for instance,” he said.
The mine’s owner, ENGIE, is measuring its rehabilitation work against a 2009 work plan which set out a number of milestones the company intended to achieve.
“We’ve actually submitted a new work plan to the government and that’s set out a range of rehabilitation milestones and activities we need to meet over the next few years and we’re sitting very well against those now,” he said.
The plan outlines rehabilitation in the next four years will include re-profiling of the mine’s batters, improving stability of the former mine and rehabilitation around its surface.
“After that four-year period, we’ll be looking to physically fill the mine [with water] so that will take in the order of 11 to 12 years,” Mr Faithful said.
“That’s subject to a number of discussions with regulators and technical experts and subject to a number of technical studies that we’ll be doing going forward.”
He said the company had been looking at parcels of land that could be leased out or sold off and was attempting to identify through technical studies what the quality of the water would be like.
“What we have been saying is that it’s not going to be any worse than what’s in the Morwell River or what’s physically purchased water out of Gippsland Water because they essentially are the sources of water that we’re proposing to drag into the mine,” Mr Faithful said.
“We think it would be just as good to use for kite or wind surfing and that sort of good stuff, but would we drink it? Well that’s a whole another question and part of our ongoing studies.”