tailings vs tails

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. 

tails

noun
  • Tailings; waste. 

  • The side of a coin that doesn't bear the picture of the head of state or similar. 

  • Tailings, feints. 

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