The opinions of the CEO of Santana Minerals, Damian Spring, that were published in the ODT (17.2.26) have found their way here to us in Bendigo— the historic epicentre of gold mining in Australia.
Damian presented us with some science and engineering concepts which, to an engineer with some five decades of experience, I have to admit I had been unaware.
Maybe these new concepts were discovered by Santana and will now be offered to the wider industry. Perhaps these concepts were first published in the 9600 pages of reports which Damian commissioned. I am left wondering if Santana got value for the $8million they paid their consultants.
There are some facts which I trust will be supported by all the learned parties as they present to the fast-track process.
Arsenic.
Arsenic forms a part of many compounds. It is present in geological structures right across the Dunstan ranges.
Its occurrence increases significantly where ore bodies hosting gold are located. At Bendigo-Ophir, arsenic in the company of other heavy metals is likely to occur at more than 1000 times the abundance of gold.
This may not lead to a good outcome when what you definitely don’t want overwhelms what you do.
Yes, there will be trace amounts of arsenic in the local farm soils and elsewhere in the Bendigo-Ophir environment. These trace amounts may be a product of erosion or a legacy of past mining.
But most of the arsenic in this environment is currently locked up in the rock formations which Santana targets. Arsenic is liberated when Santana crushes and grinds the rock and then uses a complex array of chemicals to leach an amalgamation of gold and silver from the rock particles in an industrial-scale processing plant.
Does arsenic cause harm to humans ? Yes. Arsenic is a potent carcinogen and neurotoxin and there is no safe minimum exposure. Arsenic and cyanide are poisons.
There are guidelines for the limits of occurrence of arsenic in drinking water.
California is a state known as a leader in environmental legislation. Their drinking water guidelines are 2500 times more stringent than the Australian Drinking Water Guidelines. Here we accommodate the mining industry no matter the cost.
Damian suggests that Santana can change the form of the arsenic with their special process so it is inert and harmless.
Perhaps ask your GP: ‘‘If I swallow some of the common compounds of arsenic in my drinking water, or ingest them in my food, or inhale them as fine dust particles into my bronchial system, could that arsenic be bio-available to my internal organs or brain ?’’
Tailings
Santana explain that their tailings would be held in a tailing storage facility (TSF). Sounds great. But in actuality it is a temporary storage dam with many risks.
During periods of low rainfall, dust can mobilise from the surface and disperse heavy metals into the environment.
The largest gold mine in New South Wales is Cadia. After a parliamentary inquiry, the New South Wales Environmental Protection Authority issued orders against the company to control the discharge of pollutants — which include heavy metals. A class action by the surrounding farmers is under way seeking restitution for the contamination of their farmland.
Unlined TSFs pollute groundwater. The Fosterville mine is Victoria’s most significant gold mine. At a recent Environment Effects Statement hearing one of the state’s most eminent hydrologists presented evidence describing pollution of the adjacent Campaspe River. This had emanated from the TSF.
TSFs can suffer structural failure. The Cadia mine recently experienced a catastrophic failure of their TSF.
The Costerfield gold and antimony mine is our neighbour. Victoria’s state mining regulator is currently engaged in a court action against this company for failing to maintain one of their tailings dams in a safe structural condition. There was a risk of failure which would harm mine workers and the environment.
Further down the road is the Ballarat gold mine where last week EPA Victoria successfully convicted the company for discharges of sediment into the Yarrawee river.
Large tailings dams in Australia are managed under the Australian National Committee on Large Dams (Ancold) guidelines. These guidelines describe a process for the design, operation and inspection of high-risk dam structures. The Ancold process is significantly more rigorous than the process used by Santana to describe the design and operation of their TSF.
Yet our tailings dams at Cadia, Costerfield, Fosterville, Ballarat and Stawell have all failed to retain their contents.
Santana’s technical reports describe their TSF as able to withstand extreme earthquakes, such as one which may occur one time in 1000 years. Yes, some of the overburden which Santana wishes to place into their engineered landform might still be in place after an extreme earthquake.
However, it is reasonable to wonder if the contents of a 2km-long tailings dam would still be in place after it was shaken like a giant bowl of jelly.
A TSF is difficult to rehabilitate while it is standing above the natural surface. A cap placed over the structure will erode from natural weathering events and ultimately fail. It is only a matter of when.
One solution for the rehabilitation of mine tailings is the use of a cement pasting plant and the return of the treated tailings to the underground mine voids. Another is the use of a filter press to ‘‘harden’’ the tailings into a condition where they can be capped as an unnatural landform.
These two accepted solutions cost big money, at least equivalent to several years of cashflow for a mine. This may offer an explanation as to why Australian companies rarely rehabilitate their gold mining projects.
My home is several kilometres from Victoria’s failed Bendigo mining project.
More than a decade after the project was abandoned the state government is still unable to locate the rehabilitation bond monies and the mine sits as a toxic industrial wasteland.
Damian has invited an Australian mining company into your community. The risk is that this company brings with it the Australian philosophy on the conduct of mining. That philosophy is very much ‘‘Dig, baby, dig’’.
My personal view is that it would be a high-risk strategy for your community to engage with that philosophy.
- Ian Magee is a retired engineer. He was appointed by local government as a representative to the environment committee for the Bendigo gold project in Victoria, Australia.
