Work on the conversion project, which saw one of the two former paper machines at the mill converted for packaging board production, began in May 2019 following a decision to invest €350m (£308m).

The mill has now been in production since mid-January and the newly converted packaging machine is currently in a start-up phase. It will be ramped up during the first quarter and is expected to reach its designed production capacity by the end of 2021.

Producing kraftliner, the capacity of the new line is 450,000 tonnes per year and Stora is expecting the machine to generate an annual increase of around €300m for the Packaging Materials division once it is fully ramped up.

Stora said the new machine will serve global customers “in demanding packaging end-uses that require strength, purity and strong visual appearance features”.

Products will include AvantForte, which with three fibre layers is the strongest kraftliner in Stora’s portfolio. Packaging applications include fresh, fatty or moist food, as well as high-end e-commerce packaging.

In the conversion project, the pulp mill and drying machine were modified to produce 530,000 tonnes of unbleached brown pulp annually, of which about 150,000 tonnes are sold externally.

“Completing the Oulu Mill conversion is an important step in our transformation and responds to increasing global market demand for circular and eco-friendly packaging materials,” said Stora Enso president and chief executive Annica Bresky.

Hannu Kasurinen, executive vice president of Stora’s Packaging Materials division, added: “Oulu Mill will utilise state-of-the-art technology to produce a strong, material-efficient, high-quality kraftliner product. This allows us to tap into premium packaging segments with strong growth potential, such as food contact and e-commerce.”

The conversion of the mill has spelled the end for Stora’s Lumi range of high-quality, woodfree coated art papers, which had been available in sheets or reels for web offset, sheetfed and digital printing.

Around 140,000 tonnes of Lumi had been sold into the UK annually, through direct sales and via merchants Premier Paper and Ovendens who have recently adapted their ranges to be able to offer suitable alternatives to customers.

The Lumipaper sheeting plant in Antwerp, which is being converted from paper to primarily board sheeting, will utilise cutters from Oulu to enable it to provide a fast sheet service in continental Europe.

After the ramp-up of the first converted production line, Stora said the Oulu Mill will have an additional growth option in the possible future conversion of the second paper machine for packaging materials.

It said this would further improve the mill’s competitiveness, with integrated pulp availability and additional fixed and variable cost savings.

Around 400 people are employed at the Oulu Mill, including facilities personnel and logistics staff.

Separately, Stora has said it is permanently closing its US-based Virdia operations during 2021. Virdia was acquired in 2014 and has focused on the conversion of cellulosic biomass from sugar cane bagasse into refined sugars.

The operations have consisted of a research centre in Danville, Virginia and a demo plant in Raceland, Louisiana, which will both be closed.

Stora said the closure is in line with its strategic choices in R&D to drive future growth and value creation from forest-based materials.

“Furthermore, today, the company’s innovation work focuses considerably more on applications further down the value chain instead of being a raw material supplier,” the company said in a statement.

Around 65 Stora employees and 18 contractors will be affected. The company said the closure will not have a material impact on its sales.