coalman vs pitman

coalman

noun
  • A coal miner (as distinguished from other type of miners). 

  • Someone who delivers coal. 

  • Someone who sells coal. 

pitman

noun
  • One who works in a pit, as in mining, in sawing timber, etc. 

  • A connecting rod in machinery, especially in a sawmill. 

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