The former factory in Cumberland St is to be demolished — adding to the demolition work nearing completion in St Andrew St — to make way for the city’s new hospital.
A Ministry of Health spokeswoman said there had been a few extra finds of asbestos not accounted for in the original survey.
Access was difficult in a few areas and extra workers had been brought in, keeping the programme on schedule.
Overall, the work had been planned thoroughly and was progressing well, she said.
One of the more challenging tasks was dealing with ceilings.
Scaffolding had been set up to enable removal of friable pipe lagging that spanned the H1 and H4 blocks, 7m above the ground.
As one of its conditions for obtaining a resource consent for demolition, the ministry had to complete an asbestos removal control plan.
It was continually being reviewed and updated.
Large silos that remained at the site would be one of the last parts of the factory set-up to be dismantled.
Room would be required for the cranes needed to deconstruct them.
Removal of the silos was expected to happen mid to late next year.
The top sections of the silos would be cut and carried off by crane, and this would enable a large demolition excavator to deconstruct the bottom halves.
The silos would then be recycled.
Workers at the site had been working out the best method for installing piles to support the foundations.
The traditional driven-piling method involved driving a 9-tonne pile-driving hammer into a steel casing, hammering the casing into the ground.
An alternative technique involved using a drill string — as the drill was extracted, concrete was poured into the hole and then a spiral steel casing was plunged into the concrete.
The ministry spokeswoman said the testing had provided good information, but it was too soon to draw conclusions on the preferred piling solution.
Geotechnical and structural engineers would calculate the results and present their findings and recommendations to the ministry in early 2021.