a process is shown to efficiently drill multiple , short - length , medium - radius lateral holes from a vertical well shaft . the disclosed process may be performed without the need to repeatedly pull down - hole equipment for every lateral hole drilled so as to make the lateral hole drilling process efficient . a heat pipe assembly is shown inserted into each drilled hole . the disclosed drilling and heat pipe insertion may be performed multiple times at a given vertical depth location in the well shaft . the process may be performed without the need to repeatedly pull down - hole equipment for insertion of multiple heat pipes at a same vertical level in the well level for each lateral hole drilled at that level so as to make for an efficient heat pipe insertion process . the described process may be performed multiple times at a large number of vertical depth locations .