What is HDD Drilling?

Horizontal Directional Drilling (HDD) is a drilling technique used in many different industries from mining to construction and civil projects. HDD is used in multiple industries to effectively drill through tough terrain. As opposed to vertical drilling, HDD has the advantage of being able to select specific angles and bypass certain underground hazards or rock formations. Modern technology allows HDD operators to carefully plan and map their drill site before the drill is deployed. 

As a market leader and innovator in horizontal directional drills in Perth for over 20 years, our clients are confident that the Vermeer range of utility HDD rigs offers the best possible solution for their project. For a trusted construction equipment supplier near you – give our qualified sales team a call today.

Why use HDD?

HDD is the preferred option where, for practical or design reasons, trenches cannot be dug. It is an efficient and innovative process which utilises specialised horizontal directional drills and equipment to precisely drill along a chosen bore path and back ream the required pipe.

HDD is indispensable for situations where pipe, cable or conduit need to be installed horizontally underground, such as beneath buildings, roads, rivers, or other obstacles. It ensures existing structures or assets are protected above ground or safely out of the way of the drill path. 

Which industries benefit from HDD?

HDD has been used across multiple industries for over 100 years now. Today, trenchless drilling and installation is more in-demand than ever. New projects are relying on underground installation both for design and practical reasons – and HDD is the most effective solution. The main industries that use HDD are:

– Mining 

The mining industry is one of the most important when it comes to HDD. As a major contributor to the Australian economy, the use-cases for mining operators are many and growing as the industry evolves. From accessing underground locations to the installation of new cable or explosives in open cut mines, HDD has always been an integral component of any large scale mining operation. 

– Construction and utilities 

For contractors in the construction industry, HDD offers a tried and tested solution to ensure underground utilities like water, gas, electricity and other vital connections are laid effectively and safely. HDD operations often involve the installation of PVC pipe, or even ductile metal piping systems made from iron or steel. With various applications that ensure the pipeline is able to follow specific and pre-planned pathways underground – HDD offers the ideal solution.

 How is HDD done?

HDD is a carefully planned and controlled process. From the initial planning to job execution, designers and operators are well trained in ensuring every drill is as effective and productive as possible. 

Whether it’s ensuring existing utilities are protected, or difficult underground geological anomalies are avoided, HDD drilling experts have a lot of work to do before the drill even touches the ground. Here’s an overview of the HDD drilling process:

  • Step 1 – The Pilot Hole

The first step is to create a bore plan locating existing utilities, position the entry and exit pits then drill a small diameter pilot hole to the pre-determined bore path. The pilot hole is precisely tracked using a walkover guidance system or, for more complicated jobs, a wireline magnetics type system. A transmitter near the drill head sends a signal to the engineer giving the exact position of the drill. Depth, alignment, and percent slope of the drill head are constantly monitored.

Drilling fluid is an essential component of the process. The fluid is pumped through the drill pipe to the drill bit where high-pressure jets and the bit cut through the soil. The drilling fluid then carries the cuttings back to the entrance pit.

  • Step 2 – Pre-reaming

The next step is to pre-ream the pilot hole and enlarge it to the required size. Pre-reaming ensures that a finished hole has optimal integrity. It is done after drilling the pilot hole but before the pipe, cable or conduit is installed in the pullback stage. A reamer is rotated within the hole while pumping more drilling fluid to both remove solids and enlarge the hole. Depending on the particular project and local soil conditions the pre-reaming process may require multiple passes of increasingly larger reamers. In addition to drilling fluid, additives such as Bentonite will be used to help control fluid loss or infiltration and so ensure a clean and stable hole. Other additives, such as polymers, may also be used to help break up clay soils.

  • Step 3 – Pipe Pullback

The final step and most important part of the HDD process is the pullback of the pipe within the pre-reamed hole. Pullback requires that the drill rod and reamer be attached to a swivel, which is utilized between the prefabricated product pipe to be installed and the reamer. This will prevent any stress from the drill damaging the product pipe. Once again, as the product pipe is pulled into and through the drill hole, drilling fluid is pumped through the hoke to lubricate the product pipe.

Kickstart your next project with the right partner

As one of Australia’s most trusted construction equipment suppliers, Vermeer WA & NT are here to make sure your next HDD project goes (quite literally) to plan. 

With the right equipment on-hand to match a range of capabilities and functions, our HDD range is ready to make the difference on any job-site. If you’re looking to level-up in your capability underground – give our qualified sales team a call on (08) 9479 4994 or simply complete our online enquiry form today to discuss your HDD needs with our experts. 

Related posts
Tree Stump Removal Methods | Stump Grinder vs Excavator
Wood Chipper Buying Guide
How to Choose the Best Tree Climbing Gear