lode vs strip mine

lode

noun
  • A vein of metallic ore that lies within definite boundaries, or within a fissure. 

  • A rich source of supply. 

  • A watercourse. 

strip mine

noun
  • A mine where the material above the ore is removed (stripped) to expose it for removal and use. 

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