December 20, 1918. THE COLLIERY GUARDIAN. 1285 “HARDIAX” “ALL STEEL” Coal-Cutter (Patented). Hl Fastest and most durable percussive coal' cutter extant---Steel from end to end. HUNDREDS OF THESE MACHINES ARE AT WORK. THREE BRITISH COLLIERIES HAVE OVER 150. THE HARDY PATENT PIGK CO. LTD., SHEFFIELD.