As demand for underground construction projects continues to increase, HDD operators are looking for ways to improve the efficiency, safety and profitability of the jobsite. However, the presence of hard rock often stymies the success of a variety of underground construction projects – until the advancement of HDD technology.

To keep up with industry demand and increase jobsite performance, OEMs implemented key technological features to help contractors efficiently bore through tough terrain and improve efficiency and profitability. Jobsites that were once considered impossible due to the presence of rock were now possible with new HDD technology.

One key technology that changed the future of the HDD Industry is dual-pipe drilling technology. Dual-pipe technology can help operators reduce the risk of inadvertent returns, improve boring and steering through hard rock and provides a small footprint for compact jobsites. This means that mid-size drilling equipment now had the capability and power to push through rock.

However, no HDD installation can be made without the HDD tooling parts, such as downhole bits, drill pipe and backreamers. With the advancements of HDD technology, HDD tooling also evolved to provide better performance and functionality for contractors working in hard rock. For example, OEM’s designed rock bits made with high-performance components to help extend bit life in hard rock conditions and technology that improved cutting structure and wear resistance. Contractors who understand the benefits of the enhanced tooling parts can be better prepared to implement them on the job site.

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Here are three things HDD operators should consider when selecting the best-enhanced HDD tooling parts to help them drill confidently, safely and effectively through tough ground conditions.

Choosing the Right Bit Technology

When drilling into hard soils and rock, drill bit selection is crucial. Using the appropriate tooling based on the ground conditions not only extends tool longevity but also helps operators stay productive.
In hard ground conditions, drill bits often wear down prematurely, increasing the difficulty of making steering adjustments. Choosing a drill bit that most effectively moves loose material out of the way will assist operators with steering and provide a clearer cutting path. To boost performance in these conditions, drill bits with a hard surface, such as carbide, help protect the tool from abrasive environments and extend their usability. Additionally, replaceable and angled carbide teeth can improve tool longevity and increase cut productivity.

Dual-pipe bit options include:

  • PDC bits are a productive, low-cost avenue for dual-pipe drill operators when working in softer rock. With a fixed blade and replaceable cutter teeth, these bits are designed for use with dual-pipe drills in soft to medium-hard rock formations.
  • Rotary bits with tungsten carbide inserts are the best all-around bits for dual-pipe mechanical systems. They are ideal for operators looking to increase drilling performance and productivity in hard rock formations, including solid, layered, chunky or cobble formations.
  • Dual-pipe air hammers provide enhanced productivity and steering capabilities when drilling in the hardest solid rock formations. Often, these systems are used on a mechanical dual-pipe drill in place of rotary bits when those bits become less effective and production rates drop.
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When to Utilize a Backreamer

Backreamers and drill bits both have a critical role to play in HDD projects. For example, backreamers can make projects easier, subbing for drill bits during the installation of large-diameter product. Drill bits, on the other hand, can be used exclusively to create the smaller bore paths required for many feeder lines, which extend off the main fiber backbone. On these projects, many operators forego a backream. Instead, they shoot through the hole and out the exit, and then pull the drill bit back as quickly as possible.

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When installing product in rocky conditions, operators may or may not require a backreamer and enlarged borehole. For fast installation on hard rock projects that do not require an enlarged hole, operators will want to select tooling that is designed for direct pullback and connect directly to the drill pipes without the use of connectors. However, if a project calls for an enlarged bore hole, operators will want to utilize backreamers that are specifically designed for heavy and solid rock bores and feature replaceable cutters. These features help increase productivity, reduce costs and extend the life of the backreamers when working in challenging conditions.

Boost Jobsite Uptime with the Correct Tooling

Tooling innovations continue to help contractors improve productivity in challenging terrain. It enables operators to keep the housing on the drill string when pulling back product and more easily swap out a drill bit for a swivel. This can speed up transitions – from roughly one hour to as short as five to 10 minutes – and increase uptime. The system also makes it possible to drill the pilot bore and expose the tooling with a smaller pit, which can dramatically improve jobsite productivity and enhance safety.

Enhanced Technology to Tackle Rocky Conditions

As HDD contractors need to increase productivity, safety and profits to meet demand and successfully complete HDD jobs, it is crucial that they implement and utilize technological advancements such as dual-pipe technology and enhanced tooling.

When drilling in rock, contractors should remember that they shouldn’t just switch to rock tooling and proceed routinely. Rock drilling takes planning, practice and patience. Understanding the benefits of these advancements in technology and implementing them correctly on the jobsite can help HDD contractors efficiently drill through a variety of ground conditions. Ultimately, enabling HDD contractors to achieve success on every HDD job site.

Jeff Davis is an HDD product manager at Ditch Witch.