Think Defence looks back at an anti-invasion project to deny airfields to German forces along the southeast coast of England after the Dunkirk evacuation and onset of the Battle of Britain:
A method was also sought to deny the runway to enemy gliders and transport aircraft and so the Canadian Pipe Mine was devised by the 1st Canadian Tunnelling Company. 50-70mm steel pipes were inserted into the ground using hydraulic pipe pushing equipment and laid in a criss cross pattern about 6ft under the surface. They were subsequently filled with explosives, usually a blasting gelignite called ‘Polar Blasting Gelignite’ which was very powerful.
They were also called McNaughton Tubes after the GOC of 1 Canadian Division who according to his biographer got the idea for using hydraulic rams from bootleggers who used the method for creating an offsite distribution point for their whiskey!
Only 9 airfields were identified for mining initially but this rose to include other locations, by the end of 1942, after the threat of invasion had receded, 30 locations were mined, not all of them airfields. It is estimated that over 40,000ft of pipe mines were installed.
During the war some of the pipe mines were made safe and removed because of the deterioration of the explosive filler but most were left in situ. After the war Canadian engineers were tasked with removal but it seems from reading different sources that records were incomplete and some doubt exists whether the clearance activity was completed. Additional clearance efforts were made, one that resulted in the death of a Ukrainian worker at one of the locations.