Work to restore the 10m-diameter wheel started in June 2017, about six years after it was dismantled and stored.
Two large cranes yesterday hoisted and manouevred the timber and steel wheel into position before the larger crane lowered it into a 4m-deep stone pit, which will feature some of the original stonework and is lined with timber and reinforced with steel. Installing the wheel took about an hour.
Originally installed 140 years ago, the wheel has given a new lease of life by the Phoenix Mill Restoration Trust, established about seven years ago by former North Otago resident Richard Pringle.
The project was managed by Heritage New Zealand.
While the huge wheel can be turned, that will only be done for maintenance purposes.
Trustee and Waitaki Mayor Gary Kircher said installation of the wheel was the culmination of years of work, primarily by volunteers.
''Looking back over the years it's been quite a lot of work to get it to where it is but it's been excellent with the team of volunteers. It's a real credit to what [the team has] put in and the fact it's looking the way it is now.''
Heritage New Zealand senior archaeologist Matthew Schmidt said the wheel was the largest example of its kind in New Zealand and probably one of a few that remained intact in the southern hemisphere, restored or otherwise.
''It's incredibly important ... it's a really important site. What's amazing about it is it's here and it's so close to a major city. A lot of the time in the early 20th century and post-war things like this were taken and recycled. A lot of metals were butchered and this has stayed here.''
The project was an example of groups coming together and ''making an archaeological site into a recreational site experience'', he said.
The area will now be landscaped and a car park area and viewing platform built to complete the $100,000 project.
The trust secured an $80,000 grant to fund it, and the Waitaki District Council committed $10,000 in September 2015 and another $10,000 as part of its 2017-18 annual plan.
Listed as Category 2 with Heritage New Zealand, the wheel was installed at the site of the Phoenix Flour Mill in 1878 and used to power the mill before the mill building was removed in 1905.
