When it comes to HDD, locating systems are extremely important to any job. However, a lot of drillers don’t actually know how locating systems work — which is probably how they got the nickname “Magic Box.” On top of that, many people are only familiar with walk-over locating systems, like the DigiTrak Falcon F5 from DCI, because they’re the most common. There’s nothing wrong with using this type of system — in fact, we’re pretty big fans! But wire-line and gyro-based locating systems have their place too. All three types have merits, and no matter which you choose, it needs to be fast, safe, accurate and easy-to-use.
There are many reasons that locating systems have made HDD easier. Over time, documentation and real-time reporting have become crucial elements for any bore. As locating features have developed, this process has become much simpler. Also, it’s important to know your survey area and where existing utility lines are located. These systems can offer accurate tracking which leads to a more complete mapping of underground installations. Plus, there are issues to contend with, such as interference.
As we said, each one has its own benefits and features that can work for you. Ultimately, the better question is — which locating system is right for the job? There are a number of systems available, from more basic options to very advanced ones, each offering more depth and range of communication. Additionally, highly advanced systems often have a host of helpful features, such as data logging, as-built reports, ways to combat interference and more. The kinds of job sites you’ll be working on will help determine what you need.
As we mentioned, walk-over locating systems, from manufacturers like DCI and Subsite, are the most common. They’re typically used on jobs that require a rig weighing 100,000 pounds or less, which is most HDD projects. The transmitter, or sonde, that is behind the drill head sends an electromagnetic signal through the ground to a receiver positioned on the surface. The signal provides information relating to direction, angle, rotation and more.
Walk-over systems are best when there aren’t many obstructions near the bore path. They offer accurate information efficiently, especially for shallow bores. A major benefit is that they’re also relatively easy to set up. More advanced systems also have features like real-time remote guidance and multiple frequencies to avoid interference — some can even suggest the best frequency for an area based on recorded data. However, walk-over locating systems do have limitations when it comes to depth and the amount of interference they can combat, particularly near sources of water or in areas with a lot of existing utility lines.
While more powerful transmitters are sometimes enough to account for interference, if you’re having significant issues, a wire-line locating system might be your best bet. Wire-line locating systems use magnetic guidance and a wire grid to read relevant information which is sent via wire from the drill pipe to a receiver. Some systems use a gyro in addition to magnetic guidance, but gyro-based systems are really their own beast, so we’ll cover them in the next section.
Similar to walk-over systems, the data sent to the receiver determines things like the depth, angle, rotation and direction of the drill head. However, magnetic wire-line systems are able to monitor the head from a greater distance, confirming the tool’s exact position underground. Additionally, the in-ground wire’s signal is able to bypass potential interference. These factors lead to high accuracy when locating and steering, as well as precise surveying and increased protection for the driller.
Despite these advantages, wire-line locating systems can be costly and time-consuming to implement. Ultimately, whether or not it’s worth it will come down to the location of the job site, the length of the project and the conditions of the soil — particularly if you aren’t able to place a receiver on the ground over the sonde.
Some people consider gyro-based systems the most accurate simply because they don’t have many of the same limitations as other systems. For instance, they can easily access areas above the drill path, and they’re not susceptible to magnetic interference. They are also generally autonomous and do not require a coil to be placed on the surface. However, others argue that this is essentially “drilling blind,” posing concerns for both safety and accuracy. As such, both a gyro and a magnetic steering tool may be needed on certain job sites. Gyros are also rather sensitive and prone to drift.
Gyro-based locating systems certainly have their place. Avoiding magnetic interference is a huge advantage. This system may, in fact, be the optimal choice if you have at least 600 feet of clearance and need to cover a long distance. While that might not be the majority of HDD jobs, it could be relevant to you, depending on what you’ll encounter. If so, just make sure to account for it in your budget since gyro-based locating systems tend to be quite costly.
Any locating system is going to be a substantial investment — but that investment can pay off big time. Before you buy, consider the size and capabilities of the system, and how those things relate to the projects you’ll be facing. A walk-over system might work for most drillers, but again, it ultimately depends on the specific conditions of the job. Keep in mind that it can also be hard to change or update your locating system once the choice has been made. After you’ve considered factors like soil conditions, boring depth, obstacles and interference, decide which system will be the fastest, most accurate and most user-friendly.
As technology continues to develop, the speed and accuracy of locating systems will improve, giving drillers more options for data logging and improving their efficiency. Better graphic displays, improved targeting and steering — the list goes on and on. We can’t wait to see what happens next. No matter what it is, Melfred Borzall will be there. Every type of locating system has its benefits and limitations — choosing the right one is up to you.
If you’d like to know more about the locating systems we offer, such as the DigiTrak Falcon F5 walk-over system, or the transmitter housing options we have to keep the “brains” of your operation safe, contact Melfred Borzall today. We’d love to talk.