1937. Waterfront workers and seamen protested against the export of iron ore to Japan, leading to strikes and arrests.

In 1937, output from the Middleback Range, mostly from Iron Monarch was estimated at 2 mtpa. In 1939, it was referred to in England as the highest grade deposit of iron ore known in the world. In 1943, the iron Knob deposit was still delivering an average ore grade of 64 percent metallic content. In 1949, 99% of Australian demand for iron ore was met by supply from Iron Knob and