The Iron King bog iron deposits, mined during the period 1918 to 1944, are located about two kilometres north of Alta Lake near the village of Whistler. The geology of the region consists of pyritic tuff of the Lower Cretaceous Gambier Group preserved as a roof pendant within plutonic rocks of the Jurassic to Tertiary Coast Plutonic Complex. Weathering of the pyritic tuffs is a likely source of the iron.

In 1944, 5,580 tonnes of ore were mined and 2,500 tonnes of iron were recovered. Analysis of the ore indicates that it varied between 40 and 50 per cent iron and contained 0.2 to 1.6 per cent sulphur, 0.1 to 3.3 per cent phosphorous and 1.2 to 5 per cent silica (Property File - Cummings, 1944).