Cadia gold mine boss Mick Dewar details lead findings and dust issues

Mr Dewar has been in the top job at Cadia for about four months. After acting in the role since March, he was unveiled as the new GM officially in June.

A long-time engineer and a former Head of Projects at the mine, he says he's spent the last 16-and-a-half years solving problems.

He says the last few months have been "different to the sort of engineering I'm used to, but I think the most rewarding aspect out of what I'm doing at the moment is essentially working through a problem that needs to be solved".

Those problems though don't involve simple solutions.

An ongoing dust issue, the shock allegations of lead contaminating nearby water supplies in the Cadia region, the EPA fining Newcrest and a contractor losing part of his arm due to a work place accident have all plagued the mine in 2023.

Mr Dewar says transparency is the key to ensuring Cadia both works through those issues effectively and wins back the trust of the wider Orange region.

"We can't ask people or tell people how to think or feel," Mr Dewar said.

"All we can do is try and be transparent in how we've gone about things, share the information that's driving our decisions with them and ask they take the time to look at things and make up their own minds.

"(But) ... we're taking our obligations very seriously."

One of the mine's main vent rises, VR8 was commissioned in December 2020 with a particularly high air flow, Mr Dewar said.

It was then in August, 2022 Cadia released its Zephyr report, which was an independent audit which took samples from vent rises.

According to the report, the sampling measured the concentrations of total solid particles at VR8 and another vent rise, VR3, at 360 mg/m3 and 62 mg/m3 respectively.

Both measurements, but of more concern that of VR8, significantly exceed the concentration limits for total solid particles of 50mg/m3 in the Protection of the Environment Operations (Clean Air) Regulation, the EPA showed.

Mr Dewar conceded the emissions at VR8 were "quite significantly" exceeding clean air regulations, and said Cadia began working with the EPA to rectify the issue. That came after the EPA, in June 2023, issued a letter to Newcrest requiring the mine to "take all necessary action to immediately address these issues".

In response, Cadia adjusted its underground operations in order to be compliant, as well as:

Mr Dewar says those filtration measures have stemmed the flow of dust, and some more long-term measures, including a $35 million project to have fulltime permanent units filtering dust off the mine's crushing systems, will "ensure we don't fall out of compliance in the future".

However, some of the damage had already been done.

It was in February, 2023 when residents from the Cadia region approached the mine and disclosed they had self tested water tanks and were concerned about elevated levels of lead, copper and nickel.

Ellie McNamara and her family were part of that process, and at a community drop-in session in Millthorpe organised by the NSW Environmental Protection Authority to investigate continuing dust problems stemming from the Cadia, Ms McNamara said for the past three months the family has been carting water because their home water supply is too contaminated.

"Our metal levels are high in all areas," she said in May, 2023.

"The amount of sludge is really high and the worry is when we get heavy rains it stirs the sludge up, bringing those metals into our drinking and washing water."

Mr Dewar said the mine "took those concerns seriously".

And Cadia did three things: embarked on a sampling program, commissioned a lead isotope fingerprint study and then engaged in a health risk assessment.

The results from the third aspect of that plan - the health risk assessment - will be known in August, but the initial two steps in Mr Dewar's three-point plan, which incorporates water samples from 144 tanks across the Cadia region and compares them with Australian Drinking Water guidelines indicates water is safe to drink.

He said the sludge scrapings from 88 tanks in the region were sent to the University of South Australia, and those results were interpreted by professor Brian Gulson. The final isotope interpretation report was received on July 14.

According to the report, 74 of the 88 samples have no correlation with Cadia ore. Of the remaining 14 samples, the Cadia ore and district soil samples exhibit similar characteristics and, coupled with the low concentration levels recorded in those test results, it's not possible to determine a source for the lead.

"So even if you assume that it was Cadia Ore and not soil, the levels of lead found in those tanks was so small it's not a concern.

"To address the concerns from the community about lead in tanks, I'd ask people to read the reports and go back and look and consider the test work we did and the sampling work we did which was also mirrored, to a lesser extent, by the department of health, which showed and demonstrated their water was safe to drink," Mr Dewar said.

Mr Dewar is firm in his stance that Cadia isn't here to tell the community what to think. He says all Newcrest can do is follow through and ensure words become actions.

He says being as open and transparent with decision making as possible is something he'd like an emphasis on during his time as general manager.

He said the work to rectify the vent rise issue is an example of that, while having results from the water samples sent concurrently to Cadia Valley Operations and the resident was also an example of transparency.

"The (lead) problem is very complex and involves people's concerns and emotions, it is an issue we're very keen to demonstrate that we're very serious about and so my focus, aside from running a safe operation, has been very much taken up by ensuring we're very transparent and the people in the district can see we're serious about taking our obligations seriously," Mr Dewar said.

"We had a dust result come in that was still not achieving a satisfactory reduction, the EPA required immediate compliance, we complied ... and we have been in compliance since then, and we intend to remain in compliance."

He said the Cadia network was invested in the Orange community, and was determined not to "harm or have an impact on the community".

"It's one of our priorities," he said.

Cadia Community Sustainability Network Gem Green said it's important both the community and the mine work as one to ensure both "survive" in the area.

"Through our interactions with the community, there's certainly elements of residents out there that have made it known they have views on where we could have done better, and where we could be doing better ... and we've taken that feedback on board and if you look at the work we're doing now and the issues we're confronted, with like the dust and water and lead, we've listened to that and the approach we've taken is to be as transparent as possible," Mr Dewar said.

"We can't, and we're not going to tell people what to think or who to trust, that's not our role, and not appropriate, all I would ask is for people to look at what we're doing, look at the basis in which we make our decisions, we're trying to be transparent with that and share that, and then take the time to form their own view."

Soon, if the final hurdles are clearer, the gold mine just to the south of Orange will be "an asset" to the biggest gold company in the world.

In may, 2023, ACM reported parent company Newcrest backed a $28.8 billion takeover bid from US gold giant Newmont, following weeks of negotiations.

The mine at Cadia was described as "a tier one, world class operation by any measure" and Mr Dewar was hopeful the takeover would signal a big milestone in a year which will already mark another.

Cadia will notch up 25 years in October and with the Newmont bid still months away from completion, the mine is, Mr Dewar says, in for a big end to 2023.

"We're very proud of our site, and we want to make sure Newmont take on the asset and are presented with something they can be proud of as well," he said.

"In terms of priorities of work at the moment, the work we're doing in maintaining compliance with dust is a big one for us. Maintaing safe operations is a key one for us, and the construction work and then recommissioning work on the tailings dams is also a priority for us.

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