Approximately 1,400 people are currently working on the construction site of Metsä Group's bioproduct mill at Äänekoski Central Finland. On site, the large number of workers is actually visible only in the parking lots, which are becoming more crowded by the day. Timo-Pekka Aaltonen, who heads the project's installation work, has a natural explanation for the phenomenon.
“The majority of the buildings' walls are in place and the big components have been mounted. The workers are now working indoors with installations.”
At the same time, the new mill area has started to take shape. In addition to the vast buildings, the eye is drawn to the areas' general tidiness amidst all the construction activity.
“We are paying special attention to tidiness and order for the sake of safety, the use of space and the smoothness of work. As the number of workers on the site grows, safety at work will remain our number one priority,” says Aaltonen.
We are paying special attention to tidiness and order for the sake of safety.
What poses challenges for the work is the confined area between a railway, a river and two operational mills.
“Counting in the subcontractors, there are about 80–90 contractors working in the area already, and all of them need space. Luckily, some of the work phases can be done in the nearby pre-assembly areas.”
Project progressing on the schedule
All in all, half of the bioproduct mill is now ready. When considering different sectors of the project, with construction work the progression is approximately 60 per cent and 15 per cent of the installations has been completed.
“The biggest casting work and most of the element installations have already been carried out,” says Site Manager Teppo Virtala.
Taking into account the project's vast scale, the construction work has progressed well.
“There have been a few slight delays, which we've been able to catch up. The equipment installers have always gotten to work on time.”
Concrete work still needs to be carried out in wood processing, the drying department, the baling department and the effluent treatment plant. The pile driving related to the foundations of the sulphuric acid converter is underway, and the construction of the measuring station has begun with earthworks.
According to Virtala, the basins of the effluent treatment plant and the mill area's chip piles represent particularly challenging constructional objects.
“The outer edges of the chip piles are 100 metres in diameter and the stacker in the centre will rise to a height of roughly 28 metres. On top of this, we'll be installing the chip feeder system.”
The purchases and design work related to the bioproduct mill are nearly complete.
In 2015, the focus was on construction work and installation work started at the beginning of 2016. Production trials will begin at the mill in spring 2017, and it will be inaugurated in the third quarter of 2017.
As the construction work progresses, the focus of work has shifted to installation.
“For example installation work is going on in the causticizing plant, the debarking department and the evaporation plant. In addition to equipment, pipes and cable trays are being installed in the pulp mill, whereas at the recovery boiler, we are erecting the steel structure and the boiler itself, including its equipment and the electric filters,” says Aaltonen.
Virtala and Aaltonen emphasise the significance of seamless and transparent cooperation between the installers and the builders. The coordination in the project has been in sync.
“During one week, for example, 30 massive transportations from the pre-assembly areas will arrive to the site. The schedules must be planned to the minute so that the transportation trucks can drive through the area’s tens of cranes and other traffic,” says Aaltonen.
The pace speeds up towards the autumn
The site will not halt even during July; rather, the pace of work will only accelerate towards the autumn. Then the project will see its busiest weeks.
“We will be dealing with 7–8 ongoing work phases at the same time. The construction of the pipes, for instance, will be an extremely challenging stage which will measure the smoothness of the cooperation. I have strong confidence in the experienced professionals to achieve an exemplary outcome,” says Aaltonen.
The bioproduct mill's construction site in numbers
- All in all, half of the mill is complete.
- In July the workforce on the site totalled approx. 1,400 people.
- Counting in the subcontractors, installation work involves about 90 and construction work about 360 contractors.
- Of construction work, 60 per cent is finished; the corresponding figure for installation work is 15 per cent.
- Approximately 30 transportations from the pre-assembly area arrive to the site every week.
- The heaviest lift is 170 tonnes. It requires a 1,250-tonne crawler crane.
- The turbine's heaviest parts weigh 270 tonnes, and they are hauled to their places with a jacking technique.