30 million tonnes of potentially acid forming tailings, including most of the 43,700 tonnes of chemical used in ore processing. Many of these are highly toxic, including sodium cyanide, arsenic, caustic soda, copper sulphate, zinc sulphate, lead and zinc collector.

It will also hold 17-20% of the lead, zinc and silver mined that is lost during processing.

On a major geological fault line above the water table at the headwaters of the Lawson Creek, which flows into the Cudgegong River at Mudgee.

The dam has a footprint of 112.5 hectares, across uneven ground.

Bowdens is proposing to construct a continuous geosynthetic impermeable liner base over this large area, in the hope that it will provide full impermeability for centuries to come.

This seems unlikely, and of real concern is what happens once mining is finished? Whose responsibility will it be to maintain the liner and ensure the dam isn’t leaking toxic chemicals into the environment?

There is no track record to provide proof that containment designs like this work across this scale or timeframe. In other words, it’s never been done before.

Bowdens’ own proposal acknowledges a leakage rate of 1.6mL per day, at best. The dam is designed to leak, and if this mine goes ahead that will be something the community has to live with.

Forever.

There is no plan to drain or remove the tailings dam, meaning it will remain in situ forever. Bowdens has acknowledged leakage from the dam will continue after mining stops, but there is no plan in place to fix this or manage it.

What does this mean? It means permitting Bowdens to build and operate this dam will sentence our region to a toxic intergenerational legacy. The dam will be there forever, and generations to come will have to live with the consequences of leakage of toxic chemicals into a currently pristine environment.