How many tons of iron ore did Sweden export to Germany in 1939?

In the year before the war Germany received 22 million tonnes of iron ore from various sources. It produced around 10 million tonnes of its own each year, of low quality, which it needed to blend with high-quality material from other countries, such as Sweden, which supplied it annually with 9 million tonnes. Of that volume, 7 million came from Kiruna and Gällivare, in Lapland, and 2 million from the deposits in central Sweden, northwest of Stockholm.

The ore is mined at Kiruna and Malmberget and reaches the ports of Luleå and Narvik by rail. Ore from the northern region was shipped from Luleå and sailed down the Gulf of Bothnia to the German ports on the northern Baltic: Lübeck, Swinemünde, and Stettin. The other route went by rail to the Narvik station and from there by sea, along the deeply indented Norwegian west coast, to Germany. Narvik, well above the Arctic Circle, remained open to ore shipments all year round.

German industry depended heavily on imported ore from the mines of Swedish Lapland, and most of it was shipped through the ice-free Norwegian port of Narvik. On the British side it was argued that the Narvik ore traffic should be stopped by laying a series of small minefields in Norwegian territorial waters in succession. On 3 April the War Cabinet authorized the mining of the Skjaergaard, and on the morning of Monday 8 April 1940 the British informed the Norwegian authorities of their intentions and carried out Operation Wilfred.