Fonterra has reopened a milk powder dryer following the collapse of a raw milk silo at its factory in Southland.

The five-storey-high silo collapsed about 1.50pm on September 16 this year.

Fonterra's chief operating officer global operations, Robert Spurway, said today that milk was flowing again through its ED4 milk powder dryer at Edendale, Southland's biggest dryer, after a lot of work to get it operating again.

"We've engaged a strong team of third party experts and engineers to work alongside us throughout the clean-up and investigation.


"That has allowed us to get the dryer back up and running as quickly as possible while also giving us further assurances that our site is a safe place for our people to work," Mr Spurway said.

"While it has been a challenging time for those on site and for our local farmers, the spirit and collaboration the team and the community have shown over recent weeks has been encouraging."

Fonterra continued to work with contractors and Worksafe New Zealand to fully understand the issues that led to the silo collapse, he said.

It had inspected its silos of a similar age and design across the country to ensure no other collapse happened.

With ED4 working again, a project team would also gather data to help them understand "the particular pressures experienced by silos at Edendale", Mr Spurway said.

Silos faced different pressures depending on a wide range of factors, such as ground vibration, wind and exposure to the elements, he said.

"As we bring the site back up to full capacity, we will take the opportunity to monitor and gather further information from our silos that will help make all Fonterra sites safer places to work, including taking real-time data from several silos to give us more visibility on loading strains."

Fonterra was still working on bringing the second of its two affected assets - its milk protein concentrate plant - back online and expected to have that work done in late November.