Dunedin Gasworks Museum Trust chairman Jonathan Cweorth was very pleased the painstaking work by Naylor Love contractors to remove about 4000 of the cracked chimney’s bricks one by one, reducing its height by four metres, and brace it with wood had been a success.
"The chimney is stable for the moment and is now awaiting a full seismic assessment and also a study by specialist consultant Egis to see if it can be used in its present state," Mr Cweorth said.
Built in 1880, the chimney is the oldest structure on the Dunedin Gasworks Museum site and has been fully functional up until now.
"The chimney has been fundamental to the gasworks’ operations — we need it to be able to run the machines here, so we are anxious that it passes those assessments," he said.
"The boiler gets very bad tempered when it is out of use, and it is sulking right now."
Mr Cweorth said the trouble started in April, when the museum trust used a drone to capture images of the bricks and noticed the worsening cracking.
"The increased cracking was caused by metal rings inserted in the brick work during the chimney’s construction, which have rusted due to water getting in where the pointing of the bricks has decayed," he said.
"The rings expanded and pushed the bricks out of place."
The Dunedin City Council (DCC) moved quickly, placing a Dangerous Building Notice on the gasworks site and an Affected Building Notice on the neighbouring Woolworths supermarket. These have both now been lifted.
DCC property group manager Anna Nilsen said Naylor Love contractors had removed and catalogued about 4000 bricks, which were individually labelled and would be stored to preserve the option of a rebuild at a future date.
"It’s good that the bricks that were removed from the chimney have been carefully labelled and will be stored for possible future reconstruction — they are an important part of the history of the gasworks site.
"Hopefully, they can be stored somewhere here at the gasworks, so long as they can be protected from the weather."
Now the Dangerous Building Notice has been lifted, the Dunedin Gasworks Museum Trust is looking forward to being able to reinstate its full programme of activities.
"While we have been able to continue with some activities in the fitting shop, the restrictions have definitely put a dampener on our regular activities, especially our popular markets," Mr Cweorth said.
"So we are keen to get our weekday events up and running again, and more visits from groups."
Three major markets are planned for later in the year, when the weather is warmer.
Ms Nilsen thanked the "hard-working members of the Dunedin Gasworks Museum Trust for their patience and understanding" during the important safety work.
"We know how much time and effort they put into making this site the fantastic attraction that it is for the benefit of our community, and we also know how much they treasure this chimney," she said.
Once the detailed inspections of the chimney had been done by Egis, DCC would be in a better position to determine how the chimney was managed in the future.
