Horizontal Directional Drilling (HDD)

Much of the onshore cable route construction will involve excavating a trench and installing ducts into which the cables are pulled. Where we encounter obstacles such as roads and watercourses, we will use a construction technique called Horizontal Directional Drilling (HDD). HDD is a process whereby a tunnel is drilled under an obstacle and a cable duct is pulled through the drilled underground tunnel. It avoids the need for trenches, and means we can avoid rivers, roads, drains and other obstacles across the entire 57kms cable route.

Pictured here is a typical HDD rig and is an indication of what you might see at one of our drilling sites.

The following is a simple graphic  of how an HDD works.