Many of he colliery companies set up their own offices in Cardiff in the 1850s and 1860s, whilst others operated through agents in the town. In addition the Crown Patent Fuel Co. was set up at Blackweir in Cardiff before 1860 for the manufacture of coal briquettes mainly for home consumption, followed in later years by the Cambrian Patent Fuel Co. and others. In addition to the coal companies, the iron companies also had their Cardiff depots eg Cyfarthfa, Dowlais, Penydarren, Plymouth Forge, Aberdare Iron Co., Gadlys Iron Works, Llynfi Iron Co., Rhymney Iron Co., Ebbw Vale Iron Co. and Forest Iron & Steel Co. In the mid-1850s the Dowlais Iron Co. had experimented with the Bessemer Process for the production of steel, but local iron ores proved to be unsatisfactory for use in that process. As a result iron ore began to be imported in the 1870s mainly from Spain, and companies such as the Bilbao Iron Ore Co., Somorrostro Iron Ore Co., Bongstoe Shako Ore Co. Zubiro, Jugo & Co., Christobel Manzenos & Co. all had offices in Cardiff. At this time too the Dowlais Co and the Consett Iron Co of Durham joined forces to form their own Spanish ore company, the Arconcera Co. of Bilbao. In addition to the import of Spanish ore, Cumberland ore was also being brought in via an agent of the Cumberland Haematite Iron Co.
Some idea of the trade being carried out from Cardiff in the 1850s can be seen from the fact that in 1852 a little under 900 foreign ships visited the port, of which half were French, over 100 German, over 70 Scandinavian, over 50 Dutch, the remainder being Belgian, Italian, Greek, and Turkish. By 1860 22 countries had established Consulate Offices in Cardiff to look after the interests of their nationals in Cardiff.