rubble vs tailings

rubble

noun
  • The broken remains of an object, usually rock or masonry. 

  • The whole of the bran of wheat before it is sorted into pollard, bran, etc.. 

  • A mass or stratum of fragments of rock lying under the alluvium and derived from the neighbouring rock. 

tailings

noun
  • The waste that remains after the minerals have been extracted from an ore by ore dressing. 

  • The feints, the last fraction of product obtained at the end of distillation. 

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