Anyone closely following the construction of the Dakota Access Pipeline has likely heard or read about the use of horizontal directional drilling or HDD. While not an everyday term, HDD technology has arguably transformed many facets of the construction industry since its inception in the early 1900s.
HDD is used to install underground pipe when trenching or excavating is not practical. By using a surface-launched steerable drill bit, construction crews are able to insert pipe deep beneath the surface without disturbing the surrounding landscape. Major infrastructure projects like Dakota Access commonly rely on HDD to cross roads, rivers, and other environmental or culturally sensitive areas. HDD is also frequently used in urban areas for developing subsurface utilities like water and sewer.
Michels Corporation—one of the lead contractors for the Dakota Access Pipeline—has put together an excellent video detailing both the HDD process and its applications.