Process and installation for drilling holes in the earth's crust under freezing conditions

Abstract From the Canadian patent

Process for drilling a hole in the earth's crust in which the bottom of the drill hole is frozen in front of or near the drill bit by a cold drilling liquid in which liquid particles that have been frozen to solid parts or have been solidified have been taken up whether or not by addition. In this way the bottom of the drill hole is always so hard - also upon drilling in soft or plastic formations such as clays, - that, use can be made of diamond drill bits or other drill bits normally used for hard formations, in order that the number of times a drill bit is to be replaced can be strongly reduced. The purpose of adding ice is to make it possible for a sufficient amount of frigories per …