An Elementary Class-book of Practical Coal-mining

Description:

Book digitized by Google from the library of the University of California and uploaded to the Internet Archive by user tpb.

subjects: coal,  pressure,  feet,  shaft,  inches,  rope,  weight,  seams,  air,  seam,  square inch,  cubic foot,  compressed air,  total pressure,  winding engines,  carbonic acid,  square foot,  tail rope,  full corves,  winding engine