DCHP-1 Online

double-jacking [< double + jack fellow, laborer] Mining

• n. a method of drilling in which one man strikes with a double-jack a drill-steel held and rotated by his mate.

  • 1944  [Caption] Double-jacking. Drilling a down hole with an 8-pound hammer.
  • 1963  There were no Yukon engines to create compressed air. Double jacking was the order of the day, the heavy sledges driving steel deep into the native rock.