Blog: Metso Insights
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"The foundations of our worldview are written in stone"

This was the view of the distinguished Martti Lehtinen, Professor Emeritus of geology at the University of Helsinki. One needs to be able to “read” rock. A story can begin with a grain of sand, which has ended up on the highest mountain peak. Or the other way around; mountain peaks can become grains of sand at our feet. It can also be said that stones contain the key elements of a functioning society. In some cases, over the course of its geological journey rock has become the secret store for the most precious minerals that society needs for its raw materials.

The layman’s sample practice of the Geological Survey of Finland (GTK) are unique in the country, and support the search for and study of the country’s raw material resources. This kind of activity is rare internationally: the only similar activities are the “mineral hunts” organized by the Geological Survey of Sweden in Northern Sweden and Greenland. There is room for far more extensive amateur mineral sample collecting, as this work is well suited to glacial regions. Boulder surveys are particularly useful for finding mineral deposits that extend upward to the surface of the bedrock.

From layman’s sample practice to mining operations

A layman’s sample (kansannäyte) is a sample of rock, mineral, or soil sent to a geologist or other type of expert by a rock hobbyist. In Finland, 32 of the studies have led to metal ore mining operations being set up. Almost all gemstone-related findings have been made by hobbyists. Amateur samples continue to provide important hints of potential mining sites for valuable raw materials that remain hidden in the Finnish bedrock.

Ordinary people collecting rock samples is a long-established form of ore exploration in Finland, dating back to the time of Swedish rule in the sixteenth and seventeenth centuries. The activity really took off only in the 1740s, however, under the initiative of Daniel Tilas, an assessor from the body that oversaw mining activity in the kingdom at the time. The layman’s sample practicein Finland has continued ever since then, and the overall contribution of the practice to mineral exploration in Finland has been remarkable. The most important ore deposits were found in the twentieth century. Most of the most economically important ore deposits were discovered with the aid of layman’s samplesin the 1950s and 1960s, at a time when the Finnish state was searching for ores to meet its own needs. One of the most important finds was a boulder found in 1908 in Rääkkylä, eastern Finland, on the site where the Kivisalmi canal was being dug. This led to the discovery of ore deposits in Outokumpu and the opening of a mine there in 1910. The 1908 find can therefore be seen to mark the beginning of the modern mining and engineering industries in Finland.

Geologist Lassi Pakkanen at work at the laboratory of GTK. Photo: Kari A. Kinnunen

How do I get started with mineral hunting?

Searching for stones and minerals is a great hobby for anybody, and can be easily combined with hiking and many other outdoor activities. In addition to enjoying the flora and fauna as you go, you will also get to know the ground beneath your feet. Mineral hunting also makes a great theme for a hiking excursion with schoolchildren, for example.

The hobby does not require any expensive tools. Here is what you will need to find mineral deposits and make an initial rough examination of them:

  • enthusiasm for hiking
  • protective goggles
  • a rock hammer for removing specimens
  • a magnifying glass and a steel spike for examining the minerals and testing their hardness
  • a magnet for testing the magnetism of the samples
  • a porcelain fuse or anything else hard and sharp enough to scratch the mineral sample to determine its scratch color.

If you are a Finnish speaker, you can learn about rocks and minerals with the help of Metso’s Kivikone guide (in Finnish). The website also contains video tutorials to help you learn to identify different minerals.

 

Satu Hietala (M.Sc. (Geol.), D.G.Fin, 

Geologist, gemologist

Mineral Resources, Geological Survey of Finland

PO Box 1237 (Neulaniementie 5), FI-70211 Kuopio, Finland

+358 29 503 3005


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Blog: Metso Insights

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Satu Hietala

Geologist, (M.Sc. (Geol.), D.G.Fin

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