Polyurea reinforces thickening pools at the Terrafame production plant

The rapidly growing multi-metal company Terrafame produces nickel, zinc, cobalt, and copper for international markets. For a few years now, it has utilized FSP’s versatile surface treatment expertise at the Sotkamo mine metal plant in northern Finland.

The partnership has included research and development, surface treatment projects, and polyurea coatings.

The cooperation began in 2016 with a comprehensive research and development project, during which FSP looked into developing a painting system for Terrafame at the Sotkamo production plant. Terrafame had earlier commissioned surface treatment services from various partners.

”In 2016, we started the research by placing test plates in the mine area that were either coated or painted with different painting systems. The following year we looked into how corrosion had affected the plates. Based on this test, we determined the best painting system to protect the steel structures of the Sotkamo mine and metals production plant from corrosion,” says Quality and Development Engineer Jukka Savilampi of FSP For Surface Protection Oy.

The research was initiated mainly by the diploma thesis of Terrafame’s Maintenance Designer Jani Räisänen, in which he investigated the effects of corrosion on steel structures. Terrafame’s Maintenance Development Engineer Joni Seilonen has also been involved in the project.


In addition to research and development, FSP has also carried out some surface treatment projects at the Sotkamo production plant. These projects have involved the steel structures and thickening pools at the plant.

According to Räisänen, the goal is to improve the durability of the production equipment surfaces, thereby increasing the lifespan of structures and improving the manageability of lifecycle costs.

The Terrafame production equipment are used to produce nickel, zinc, cobalt, and copper, suitable for example for the manufacturing of stainless steel, corrosion protection, and battery chemicals. The production process stages include mining and ore handling, bioleaching, and metal extraction.

Terrafame’s Joni Seilonen (left), Jani Räisänen and FSP’s Jukka Savilampi have worked together to determine the best painting systems to protect the steel structures of the Sotkamo production plant.


”Surface treatments are very important, because corrosion can progress rapidly, especially in severe climate conditions,” says Seilonen.

In addition to more traditional surface treatments, FSP has also carried out polyurea coatings for extreme conditions at the production plant. These special coatings have been applied to several thickening pools, each with a diameter of 30 metres.

According to Räisänen, the goal was to make the pools extremely wear-resistant, because the thickener pools are constantly filled with fluids and are therefore under humidity stress. Savilampi states that polyurea was a good choice here, because it can withstand being submerged very well and hardens quickly.

The strengths of polyurea are its durability and flexibility, which enable it to withstand wear and extreme stresses. It is also seamless and waterproof, making it an excellent water insulation material. The projects were carried out during the maintenance shutdown in the spring and over the summer of 2018. The work was done by FSP’s surface treatment professionals.

”So far our experiences have been positive and profitable. FSP’s Jukka Savilampi has been an excellent contact person with whom we have been able to review all projects. The quality of the work has been high all the way. Documentations and quality controls have been very good. There have been no deviations,” tells Räisänen.

”We have been able to stay on schedule and within the budget during our cooperation. We will keep working together in the future.”


  • A Finnish multi-metal company.
  • Develops the cost-effectiveness of the metal industry by novel operational modes.
  • Currently produces nickel, zinc, cobalt, and copper.
  • Mine and metal production plant is located in Sotkamo, Northern Finland.
  • Their goal is to conduct environmentally sustainable, safe and profitable operations.
  • Annual turnover approximately 220 MEUR (2017).
  • Directly employs some 650 professionals.