The term 'Coal-Rich Valley' refers to the Saar region in Germany, which is a historically important coal-mining area. The Saar region is located in the southwestern part of Germany and has been an important source of coal since the 19th century. The region is known for its rich deposits of coal, which have been mined for centuries and are still being mined today. The coal-rich valley has also been an important industrial center, with many factories and businesses relying on the coal industry for their livelihoods.