What is it?

A temporary casing, or hole lining, can be sunk into the ground as drilling progresses. This casing acts like a wall stopping the hole collapsing. If sunk with a cutting tool at the bottom that is larger than the casing and if it is repeatedly twisted, lifted and dropped to lower it, it will be loose enough to remove with bottle jacks or winch. Consallen, in the UK, sell a range of drilling equipment including temporary casing, further details can be found in this document and on this page