lava vs tailings

lava

noun
  • The molten rock ejected by a volcano from its crater or fissured sides. 

  • Magma. 

  • A shade of red, named after the volcanic lava. 

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 lava and tailings occurred in a corpus of books? (source: Google Ngram Viewer )