In the middle of a rural suburb in Christchurch, tension between residents and the quarrying industry is coming to a head. There’s been protests, threats of legal action over the quarries and hundreds of people have turned up to community meetings. The driver for this disquiet? Concerns over the dust coming from the quarries, and what it means for residents’ health. And, this week a highly anticipated scientific report on the amount of dust, and whether it is indeed harmful to public health, was released.
For more than 100 years, quarries have been operating in Christchurch. The first ones were scattered around the west of the city. By the 1970s quarrying was mainly in three areas; Miners Road and Pound Road in Yaldhurst and McLeans Island.
Why these areas? Geology. The Canterbury Plains are mainly made of gravel, which is close to the surface in these areas, making it sustainable for quarrying.
Over time, more residents moved into the area causing land use tensions to begin to bubble in Yaldhurst.
The Yaldhurst Air Quality Monitoring programme starts.
The programme aimed to understand if RCS was present in airborne dust around quarries, and if so, was it at a level that would pose a long-term public health risk to residents. It also aimed to understand the level of nuisance dust, commonly referred to as PM10.
The monitoring was split into two parts; RCS and PM10.
The PM10 monitoring ran from 22 December 2017 to 21 April 2018, while the RCS monitoring ran from 19 January 2018 to 21 April 2018.
Community tensions continue to increase
Everyone from the councils to the residents waited anxiously for the results. Meanwhile, an independent hearing panel granted consent to an existing Yaldhurst quarry to expand. However, that consent was contingent on the Mote monitoring results being below specified long-term exposure levels for respirable crystalline silica. Granting the consent was met by some community outrage, as seen in this story:
This decision has been appealed by a group of Yaldhurst residents and is now before the courts.
Just before the Mote monitoring results were published, residents turned up en masse to a meeting at the Templeton community centre to hear from Christchurch Mayor Lianne Dalziel, Selwyn Mayor Sam Broughton and Selwyn MP Amy Adams about quarries. The drive for this meeting was based on Fulton Hogan announcing they will apply for a consent later in the year they will apply for a consent later in the year to make a new quarry in the area.
How close should a quarry operate to someone’s home?
At the meeting, Mayor Dalziel announced the councils and Environment Canterbury would be writing to the Ministry for the Environment asking them to consider the issue of separation distances between residential properties and quarries, given the current lack of New Zealand-specific guidelines.
The letter, sent on 18 June, was signed by Environment Canterbury, Christchurch City Council, Selwyn District Council and the Canterbury District Health Board.
The Yaldhurst Air Quality Monitoring programme results.
The results of the Mote monitoring were made publicly available on 22 June 2018.
"There’s no serious public health risk based on these results" – Dr Ramon Pink – Canterbury Medical Officer of Health.
The RCS results were compared with an international guideline – the Californian non-occupational guideline of three micrograms per cubic metre (3 μg/m3).
Over the three months, there were only two results detected, and both were well under this guideline.
What is RCS?
The PM10 results also showed no long-term public health risk, however Environment Canterbury chief operating officer Nadeine Dommisse said they showed there was a nuisance dust issue from time to time that needs to be addressed.
“We appreciate nuisance dust is a concern for some residents, and we want them to know we have, and are, taking this seriously.”
What will be done to manage quarry dust?
We agree quarry dust management hasn’t been good enough in the past. It is clear more needs to be done by all parties, including the quarry operators, themselves to avoid dust nuisance issues.
Dommisse announced Environment Canterbury was taking a tougher approach to quarry dust management.
We’re going to require all quarries within 500 metres of someone’s home to install dust monitors on their boundaries by December 1. If there is no practicable reason why these boundary monitors are not in place by December 1, we will be taking enforcement action.
An example of how these boundary monitors work is that they run continuously and must be fitted with an alarm system to send the quarry manager a message if it starts getting close to the threshold level for nuisance dust. If the alarm is triggered, the quarry will be expected to take whatever action they need to, such as stopping work or adding more water carts, to ensure the dust doesn’t breach the Ministry for the Environment’s one-hour nuisance dust guideline level. If the guideline is breached, the quarry will need to stop operating until dust has returned to acceptable levels.
Quarry operators would have to make this data available to Environment Canterbury, and inform the regional council if there was a breach.
“If a quarry breaches the trigger level, we’ll investigate to find out what action they took to stop dust leaving the quarry before deciding what further action we need to take,” Dommisse said.
It will take time to rebuild trust between the residents, Environment Canterbury and the quarry operators. The Mote results, while addressing the RCS issue, have raised the need to address nuisance dust (PM10) – and only by doing so effectively will the quarries and councils begin to deliver what the residents have asked for.
Dommisse believes Environment Canterbury’s new tougher approach to dust management will help deal with the nuisance dust issue, especially if some quarries apply to expand. This coupled with some national guidance around set back distances would help ease land use tensions.
“I’m hopeful that we’ve found a way forward that will work for the community, the quarry operators and the local authorities.”
What happens when the quarries lifespan is exhausted?
Many Christchurch residents will have ridden their bike, walked their dog or gone for a run through Halswell Quarry without giving it too much of a second thought. However, it once was a working quarry that produced the distinctive blue-grey stone which can be seen in many of the city’s heritage buildings, including the Canterbury Museum.
According to Christchurch City Council, the quarry ran until 1990 when the reserve of useable rock was exhausted.
The Council then decided to restore it into a recreation reserve and wildlife habitat, with more than 250,000 trees and shrubs planted.
Looking at all the quarries in the area today, you can imagine what they might look like in another 20, 30 or 50 years.