ThyssenKrupp is operating the second-biggest terminal of the Rotterdam port--the fourth-biggest port worldwide with 430 million metric tons a year in turnover of merchandise.
About 90% of the company's raw material is handled there.
ThyssenKrupp will have to import more coal, as coal production in Germany is set to cease gradually by 2018.
The expansion of coal surfaces at the port will result in an increase of about 50% in storage capacity and enable the company to handle about one third more of coking coal than previously, Steinhoff said.