corf vs gold mine

corf

noun
  • A large basket, especially as used for coal. 

  • A wooden frame, sled, or low-wheeled wagon, to convey coal or ore in the mines. 

  • A container (basket, wooden box with holes etc.) used to store live fish underwater. 

gold mine

noun
  • A mine for gold ore or metal. 

  • A very profitable economic venture. 

  • A plentiful stockpile of something sought after. 

How often have the words corf and gold mine occurred in a corpus of books? (source: Google Ngram Viewer )