Otanmäki Mine Oy – A new life for an old mine

Otanmäki Mine is aiming at high-quality primary production for international markets by using the mineral resources of an old mine. Circular economy solutions provided by the Geological Survey of Finland (GTK) help to enable production from the mine’s tailings to speed up the development of the mining project.

The challenge for Otanmäki Mine

New production from an old mine

The goal of Otanmäki Mine’s mining project is to restart the Otanmäki mine area, which was closed in 1985. The primary products have remained the same: vanadium pentoxide, ilmenite and iron ore pellets. Vanadium, the most valuable product, is used mainly as an alloy to increase the strength of steel. In the automotive industry, high-strength steel can be used, for example, to reduce the total weight of electric vehicles which, in turn, increases the vehicle range.

After being closed, the old mine filled with water, and the mine area’s tailings dam contained 10 million tonnes of material, the composition of which was not known precisely. What was known of the area’s mineral resources came only from the previous operator’s reports. “We launched a research project for the tailings dam to prepare for the actual mining project. Much of the sand left over from the beneficiation process can be used in various infrastructure construction sites and as raw material for concrete manufacturing. This is purely a circular economy project, in which we can have access to ilmenite, the valuable mineral contained in the tailings and develop a solid base for our mining project”, says Jouko Jylänki, CEO of Otanmäki Mine.

GTK offering solutions

A boost from a circular economy solution for the tailings dam

Based on GTK’s estimate of the mineral resources, it was known that the average ilmenite content in the material contained by the tailings dam was 16%. The goal set for the beneficiation process was a yield of 50%. GTK Mintec’s Pilot Plant and Laboratories in Outokumpu acted as a testing and research platform for the beneficiation process. On the basis of piloting and testing, the most optimal gravity separation method was selected for the tailings. It helped to achieve the targeted yield and a high level of quality, which would be acceptable to the markets.

“No other service provider in Finland, nor Europe, has similar extensive testing and research services for the beneficiation process such as GTK Mintec. GTK’s operations are trusted to such an extent that having GTK as a partner is also a strong signal for investors and gives credibility to the project”, Jylänki notes.

No other service provider in Finland, nor Europe, has similar extensive testing and research services for the beneficiation process such as GTK Mintec. – Jouko Jylänki, CEO, Otanmäki Mine Oy

Going forward

From the initial project to starting a new mine

The initial tailings dam project will take at most eight years. This produces a reasonable profit, which will lower the threshold to launch the actual mining project. The water in the mine will be pumped to the tailings project’s processes, thus draining the mine at the same time. Circular economy solutions in the old mine area will produce a profit, generate trust in the markets and strengthen the social licence in the region.

“Together with GTK, we can overcome our challenges, as projects are planned and discussed thoroughly beforehand. As a whole and with its initial projects, Otanmäki Mine is certainly one of the most promising Finnish mining projects around”, Jylänki concludes.

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