The quake hit the LKAB-owned mine, one of the world's largest iron ore mines, shortly after 3am.
Sweden is not an area that normally experiences a lot of powerful seismic activity, but tremors due to mining activities are not uncommon. However, with a magnitude of 4.1 this was Sweden's biggest mining-related earthquake ever.
“Even from an international perspective it's a large mine quake,” Björn Lund, a seismologist at Uppsala University, told the TT news agency.
It is not the most powerful earthquake in Sweden overall, with the record held by an earthquake in Sjöbo in southern Sweden that measured 4.3 on the Richter scale.
The quake in Kiruna on Monday morning could be felt around 20 kilometres away, said Fredrik Björkenwall, spokesperson for LKAB. “When ore is mined, holes and cracks occur which cause great stress (to the bedrock). This one happened at 1,108 metres below the surface,” he told TT.
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Thirteen people were down in the mine at the time, but no one was injured and they were all able to get out using cars. However, the quake temporarily knocked out the water pumps in the mine, which sparked concern that the mine would be filled with water which could in turn cause a power blackout.
LKAB workers managed to get the pumps back up and running on Monday morning, but all mining work has been halted while they continue to investigate that it is safe to resume work.
“It is unclear if we'll be able to open this afternoon,” said Björkenwall.