On Flightradar24, the plane could be seen flying back and forth.
The mystery aircraft spotted near Burträsk on Wednesday has been identified as a DC-3. Taking off from Umeå shortly after 6:00 AM, the plane executed a repetitive flight pattern, steadily traversing northeast between Flarken and Burträsk.
Flightradar24 revealed the mysterious aircraft to be a DC-3 registered in Canada.
The unusual flight pattern has a simple explanation. Boliden Mineral AB is conducting geophysical surveys in designated areas of Skellefteå municipality.
According to a company information sheet, the purpose is to "collect gravimetric and magnetic data for potential further exploration." The sheet also includes a map outlining the areas of interest (marked in red) and the aircraft's general flight path (marked in blue). While the map has been slightly updated since the information sheet's distribution, it still provides a reasonable indication of where the plane might be flying.
Please note: The map provided outlines the intended areas for prospecting flights, but it may have been updated since the initial information was distributed. The blue squares indicate the general area the aircraft may fly over, while the red-marked areas represent the specific locations where measurements will be taken, according to information from Boliden.
Anaïs Brethes, a Boliden geophysicist specializing in prospecting, explains that the DC-3 is conducting a "passive measurement" to detect potential mineral deposits underground.
– If the data reveals intriguing geological features, we can then move on to ground-based surveys, she says.
Bell Geospace, a contractor, conducts the flights for Boliden. The aircraft is equipped to measure various properties, including magnetic variations and bedrock density.
– By analyzing these contrasts, we gain valuable insights into the ground's physical characteristics, Brethes explains.
The flights commenced in early May and are expected to continue until July 1, weather permitting.
– Stable flying conditions are crucial, Brethes says.
– Strong winds or turbulence force us to postpone flights and resume them later.
The plane follows parallel flight lines spaced 100 meters apart. While this requires maneuvering space, Brethes clarifies that actual measurements only occur within designated areas.
Flight altitude typically ranges around 100 meters, but adjustments are sometimes necessary for safety reasons.
– Near populated areas like Bygdsiljum and Burträsk, flights reach 300 meters, Brethes explains.
– Additionally, we consider areas with bird sensitivity. Flights are either diverted or conducted at higher altitudes in such cases.
Is this for a new mine?
– It's too early to speculate, Brethes cautions.
– This initial flight campaign aims solely to identify potentially valuable geological formations containing minerals. As I mentioned, it's a very early stage – these flights are just the first step in the entire process.