Workers are believed to have been exposed to hazardous chemicals during processing at a now closed mine.
Between October and November last year, workers at Black Oak Minerals’ Manuka silver mine – south of Cobar in central NSW – carried out a manual acid-leaching process to extract gold from ore trucked in from Black Oak’s nearby Mount Boppy gold mine.
The process involved several workers manually mixing nitric acid with gold ore slurry in stainless steel buckets.
“During this process, workers may have absorbed mercury and lead into their blood via their skin through inhalation of vapours,” the NSW Mine Safety Investigation Unit stated.
“The process was initially conducted inside the gold room but was moved outside when excessive nitric acid fumes were given off.
“Workers involved in the acid-leaching process may have suffered from elevated lead and mercury levels in their blood.”
According to the NSW Department of Industry, mercury exposure can have toxic effects on the nervous, digestive, and immune systems, and on lungs, kidneys, skin, and eyes.
The Mine Safety Investigation Unit has begun a review into the circumstances around Black Oak’s acid-leaching process, with a report to be prepared for the Secretary of the NSW Department of Industry.
Black Oak Minerals was placed into administration in March this year, and all operations at the site have since ceased.