As with any task, if there’s more than one way to do it, then you should explore all of your options before forging ahead.
This holds true in the world of utility construction. For years now, contractors have had several options when it comes to installing water, sewer, gas, oil, electric and cable lines using trenchless methods. Whether it’s pipe bursting, pneumatic boring, ramming, auger boring or horizontal directional drilling, it’s best to know the differences and benefits of each because they’re not all one and the same.
For example, pipe bursting is the trenchless method most commonly used for rehabilitating or upgrading existing utility lines, while ramming is often used to install large steel pipes and casings up to 84 inches (213 cm) in diameter.
Every decade or so there seems to be a new trenchless method that hits the market or a technological advancement that changes the way an existing method is used, giving it new life in the battle to become the method of choice.
"With all of the different trenchless methods out there today, I think it’s a matter of contractors looking at the application and looking at the piece of equipment that’s right for a job," says Dave Gasmovic, president and CEO of McLaughlin Boring Systems.
Auger Boring: Simple and Effective
In the beginning, when the concept of trenchless installation first surfaced, there were few choices. In fact, one of the first trenchless methods was auger boring, which dates back to the early 1900s.
It’s not surprising that this was one of the first methods due to its simplicity. Auger boring uses a rotating cutting head to bore a horizontal hole inside of a casing. As the cutting head cuts through the ground, the resulting spoil is moved by the flighted auger out of the casing and the steel casing is jacked into place. It’s a simple concept, but it’s also very effective.
One of the first auger boring companies of note was Ka-Mo. A pioneer in the industry, the company had accomplished the feat of boring 5-inch- (13 cm) diameter uncased holes up to 230 feet (70 m) by 1951. It continued to dominate the auger boring business until a pipeline welder named Al Richmond began manufacturing small horizontal auger-boring machines. Gasmovic says McLaughlin Boring Systems came to be in the mid-1960s after purchasing a company called Western Boring, an offshoot company of Ka-Mo.
Over the years, horizontal auger boring has experienced peaks in its popularity, but it’s remained a constant in the trenchless industry for nearly a century — surviving economic challenges, construction trends and new products.
"I think the heyday of auger machines was probably in the 1970s and early 1980s. Then, microtunneling became a buzzword in the industry. Everybody wanted jobs microtunneled instead of auger bored," Gasmovic says. "After that, we went through a brief stint of popularity when people realized auger boring machines were probably still the most cost-efficient and practical way to do installation in many cases."
That’s not to say, however, that auger boring equipment hasn’t changed with the times. Some of the first auger boring machines were powered by old air motors that rotated smaller diameter augers. Stability issues persisted with these early machines because they could not handle medium- to larger-sized augers. Then came machines with gasoline and diesel engines. And with this invention came the ability to actually install the casing while boring.
"The first auger-boring machines drilled the hole first and then you had to pull the augers out and you slid the pipe in," Gasmovic explains. "Well, that was OK if you had good soil conditions. But where you had soil that wasn’t very stable, you’d have the hole collapse and you’d have roadways sink in."
With the new machines, operators place the auger inside a casing. The auger head bores out in front as the casing is installed at the same time. This was one of the major inventions to progress the auger boring industry because it expanded the soil conditions in which contractors could use the trenchless method.
Benefits of auger boring
Today, contractors across the globe are again realizing the benefits of auger boring. As the need for oil, gas, water and sewer line installation grows, more contractors are evaluating their trenchless method options and taking a closer look at auger boring, discovering that it’s a cost-efficient way to install steel casings between 24 and 70 inches (61 and 178 cm).
"A 400-foot (122 m), 36-inch (91 cm) diameter steel casing can be installed with an auger machine and an auger that costs about $250,000 new. Whereas, if you were to do the job with a directional drill, you’re probably looking at a machine that is $1.5 million. And a microtunneling machine might be in that range or the $2- to $3-million range," Gasmovic says.
While the cost-savings of auger boring machines is a definite attraction, being able to install a steel casing while drilling the hole remains the No. 1 benefit. Not only is it more efficient, but it also helps create extremely stable bores. "You’re not using any fluid to do the cutting," Gasmovic explains. "You may use some fluid to lubricate the outside of the casing and some fluid on the inside to help clean the auger, but you’re not actually using a water or bentonite to help create the hole. So you don’t have any subsidence of the ground."
Another benefit of auger machines is that they can perform jobs in a relatively short footprint compared to other trenchless methods, meaning you need less work area. "With an auger machine, you’re going to dig a pit on one side of the road, start there and go to the other side of the road and dig a pit to receive it." Gasmovic explains. "You don’t need a lot of room to set back and have a slow run-in for the pipe."
How it’s being used
As more governments — both in the United State and internationally — demand that utility contractors cause minimal disturbance, Gasmovic says auger boring will continue to be used. When government officials or others are faced with choosing a trenchless method for utility installation, he suggests that they first talk to equipment manufacturers and contractors who have been researching and completing auger boring projects for years. Seeking out experts in the field will help them make an educated decision.
In North America, auger boring is primarily used to install sewer lines and larger oil and gas pipelines, especially those that cross state or national highways and railroads. Often, state department of transportation officials turn to auger boring because they do not want drilling fluid being used under their roadways. "It’s the same thing with railroads," Gasmovic says.
Auger boring is especially popular in the sewer industry because it allows contractors to more accurately control the grade of the bore — which is the most critical piece of sewer line installations and often the most difficult to achieve.
For the most part, Gasmovic says auger boring machines are being used in the same way in Latin America. He says there was an auger boring surge in Latin American countries during the 1980s and 1990s as their infrastructures grew. And today, they continue to use the method for installing oil and gas pipelines as their sewer technology begins to catch up with other nations.
The trenchless method is also gaining popularity in the Middle East, where Gasmovic says his company recently sold a large auger boring machine to a municipality for installing new sewer lines. Further north in Russia, an increasing number of auger boring machines are being used to install large-diameter steam lines and gas and oil pipelines. While auger boring is a relatively new trenchless method of choice in some countries, Gasmovic says it’s been around in China since the 1960s or earlier.
Gasmovic says one reason the auger boring method is attractive, especially in developing countries, is because of its simplicity and ease of use. Unlike other trenchless methods that require experienced operators who have logged hours of training, auger boring is a simpler technology that enables government officials to easily train multiple operators.
What lies ahead?
In the coming years, industry experts say they expect auger boring to remain a popular trenchless method and expand upon its already impressive longevity.
"Auger boring is going to continue to be popular for the gravity flow sewer lines and the larger oil and gas pipelines," Gasmovic says.
Though auger boring is one of the first trenchless methods, it still must keep up with the changing market and trends. Manufacturers like McLaughlin Boring Systems are investigating new technologies to advance their machines, including a new technique to better steer the machines. "We’re all looking at better ways to control the casing, better ways to steer the auger and different ways to install concrete pipe along with steel pipe," Gasmovic says.
In addition, manufacturers are also looking at ways to extend the length at which their machines can bore. Currently, Gasmovic says, the longest bore on record is just over 650 feet (198 m), which is a good distance for an auger machine. Typically, most horizontal auger bores range between 300 and 400 feet (91 and 122 m). Having the capability to bore longer distances could dramatically change the auger boring market.
Whatever the future holds, one might predict that auger boring is one trenchless method that will still be used another 100 years from now. Its simplicity helps keep it timeless in regard to effectiveness and cost-efficiency. This is why industry experts maintain it shouldn’t be discarded as being the old way of doing things.
"People need to look at all the different methods out there when they’re doing a trenchless project," Gasmovic says. "It’s so easy to get caught up in buzzwords and what sounds new and what they’re seeing presented at conferences. But they shouldn’t overlook the tried-and-true methods."
Tara Deering-Hansen is a Technical Writer, based in West Des Moines, IA.