digger (n.)

mid-15c., "one who digs;" 1680s, "instrument for digging," agent noun from dig (v.). The communistic movement in England so called from 1649. Meaning "one who seeks gold in a prospecting place" is from 1853. In 19c. American-English, it was the name for degraded Native Americans in the West, who were so called for living chiefly upon dug-up roots (1837).