After the Second World War, the coal, iron, and steel industries indisputably represented the leading sectors of the German economy. Coal was the most important source of energy for steel making as well as for generation of electricity; iron and steel were the decisive basic ingredients not only of war production but also of peace time economy.

The heavy industries of the Ruhr were highly concentrated and cartelized. Beginning at the turn of the century, this trend had increased during the Weimar Republic and had reached it speak under National Socialism. In particular, coal and steel had been strongly integrated into the so-called Verbundwirtschaft. The motive for this process was the desire of the combines to secure the source of basic production inputs, raw materials and energy. In 1945, 55 percent of coal mining was combined with the iron industry technically, economically, and now by ownership: technically through the exchange of fuels and energy, economically through the harmonization of investments and of profits and losses, organically through the combination of mines and iron factories into integrated business concerns. The Verbundwirtschaft represented a vertical organization structure of the production from the raw material to the finished product. This connection was especially marked in the concern of the Vereinigte Stahlwerke (United Steel Works). Founded in 1926, this company, through its subsidiary Gelsenkirchener Bergwerks-A.G., extracted 19 percent of the total hard coal output, which amounted to about 35 percent of Verbundkohle (bound coal).