Canterbury medical officer of health Dr Alistair Humphrey confirmed that two independent tests – one commissioned by the residents and the other by respiratory, toxicology and public health officials from the Environment Canterbury (ECan) department – showed the dust contained 30 per cent silica. This is known to contribute to the irreversible lung disease silicosis if breathed in over a significant period of time.
As reported by the NZ Herald, local residents had complained to officials about adverse dust emissions from Winstone Aggregates’ Yaldhurst quarry for years, with some now resorting to wearing face masks outside to protect themselves.
Six homes are located less than 200m from Yaldhurst, despite Winstone’s own dust expert Richard Chilton stating quarries should not operate within 250m of a dwelling.
“It is my experience that coarse dust impacts will typically be within 100m of a source,” Chilton wrote in the company’s resource consent after the quarry was granted permission to expand in 2015.
According to reports, the local council has confirmed Winstone Aggregates’ quarry resource consent could be reviewed if the investigation found ‘unanticipated adverse effects’.
“While the council is conscious of the serious nature of the issues being raised, there does need to be a robust evidential basis for initiating a review of conditions,” Council and compliance general manager Leonie Rae told New Zealand’s Stuff news.
Winstone Aggregates general manager Ian Jones also told Stuff news the quarry’s managers took health and safety very seriously, and were working to improve its dust management procedures.
“We are committed to making further improvements and are investigating different options to help further control dust,” Jones said.
“These include changing truck movements, options to further seal internal roading and further enclosing processing plant on-site,” he added.
In 2014 Winstone Aggregates installed a wheel wash for vehicles at Yaldhurst Quarry after it received a caution about dust pollution. A year later the company received an abatement notice after digging too close to the water table. Scientific sampling showed no harmful effects on nearby drinking water.
The residents were set to meet with Environment Canterbury officials to discuss the matter at the end of March.