Deep penetrating Sampo -geophysical survey

Report: Electromagnetic SAMPO soundings at Taivaljärvi

The survey shows clearly that anomalous region coincides with the same geological structure where the Taivaljärvi mineralization is situated. Results of the Sampo method show a strong electromagnetic anomaly situated at the continuity of the Taivaljärvi mineralization and extending to depths of 1 000 m am 1 000 m in strike.

Figure 1 below: Exploration targets below known deposit down to 1 000 meter's depth along the stirike.

Sotkamo Silver commissioned a deep penetrating electromagnetic survey from Geological Survey of Finland (GTK) in autumn 2011. Purpose of this survey was to explore the assumed continuities of the Taivaljärvi orebody between 600-1000m levels.

Two methods were chosen for the survey and teams from GTK's Kuopio and Rovaniemi units performed the measurements. First applied method was an audiomagnetotelluric survey (AMT). Two survey lines were measured perpendicular to the strike of the assumed continuation of the Taivaljärvi mineralization. Figure 1. below shows the location of the survey lines (blue dots). Basemap is an electromagnetic anomaly map obtained from low altitude aerogeophysical survey performed by GTK in year 2005. Also in the map is presented the projected outline of the assumed continuation of the deep extending mineralization (red raster).

   Figure 2 below: AMT-survey lines

Results from the AMT-survey show clearly an anomalous region which coincides the same geological structure where the Taivaljärvi mineralization is situated. In the southernmost survey line the anomaly is situated between 800-1 000 m levels. In the northernmost line the anomaly is situated between 600-800m levels. Results from the southernmost survey line are shown in figure 3.

  Figure 3 below: Vertical cross section showing the deep anomaly on the southernmost AMT-survey line

Second geophysical method chosen to explore the assumed continuity of the Taivaljärvi mineralization was Gefinex 400S also known as Sampo-method. This method is also a deep penetrating electromagnetic survey and it is developed by the Geological Survey of Finland. Survey grid is shown in figure 4. Survey grid was located mostly parallel to the geological structures and also parallel to the strike of the Taivaljärvi mineralization. In the northernmost corner of the survey area, a small grid perpendicular to the geological structure was also measured.

   Figure 4 below: Measuring grid used in the Gefinex 400S survey

Results of the Sampo method show a strong electromagnetic anomaly situated at the continuity of the Taivaljärvi mineralization and extending to depths of 1000m. This electromagnetic anomaly is characterised by low resisitivities, between 500-1500 Ωm. These resitivities are similar to the known Taivaljärvi mineralization and thus strengthen the Sotkamo Silver's view, that Taivaljärvi mineralization extends at least to 1000m level below the surface. Gefinex survey also shows, that the anomalous region lies between 600-1000m levels and it's strike length is at least 1000m. True nature and quality of this geophysical anomaly has to be verified by diamond drilling. Diamond drill testing of the anomaly is tentatively planned to be performed during 2012 or 2013.

  Figure 5 below: shows the electromagnetic anomaly obtained by Gefinex 400S survey. Also in the figure can be seen the existing ore solids in red and the mine decline. Resistivity values in the anomalous zone vary from 500 Ωm to 1500  Ωm.

Sotkamo Silver commissioned also a drill hole geophysical survey from Ageos Oy in autumn 2011. Ageos surveyed some selected surficial and underground drill holes at Taivaljärvi area. Drillhole survey included measurements of IP (induced polarization), susceptibility, density, Wenner resistivity and TEM (transient electromagnetic measurement). Data obtained from drill hole geophysical logging was used in the planning of the survey grid for the Gefinex survey and also in the interpretation of the Gefinex survey results.