leaf litter vs mullock

leaf litter

noun
  • Dead plant material, such as fallen leaves, bark, and twigs, that has fallen to the ground and may be used by animals as habitat or for nest-building, eventually decomposing and releasing nutrients into the soil. 

mullock

noun
  • Overburden: waste material generated while searching for minerals or while mining, such as when sinking a shaft. 

  • Rubbish, waste matter. 

  • Tailings: waste rock from which the wanted gold, minerals, opal, etc., has been extracted. 

  • Nonsense, rubbish. 

  • A mess; the result of a blunder. 

verb
  • To clear waste material out of a mine. 

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