On June 26, Midwest Mole Inc. began a railroad crossing project in the Town of Tolono, Ill., for Feutz Construction. The project consisted of 128 ft of 60-in. steel casing to serve as a storm water carrier as part of a new main trunk line storm water system.
The grade requirement of 0.15 percent made this project challenging. As this casing was to act as the actual carrier and there was no additional tolerance between the downstream and upstream structures, it meant the grade had to be extremely accurate.
With the grade restrictions and the minimal distance of 128 ft, it was decided a guided bore would be the most economical solution. This would ensure proper line and pitch to the new storm water carrier. Due to the casing’s large diameter, Midwest Mole had to use a new installation technique that it had yet to attempt. In order to get from the pilot tubes to the required size of a 60-in. diameter, Midwest Mole recognized that a “sequential” upsizing would be required. A typical guided bore consists of installing 4–in. diameter pilot tubes followed by a reaming head or swivel and 12- to 36-in. diameter steel casing.
For this project, Midwest Mole designed and fabricated a 24-in. by 60-in. “rocket ship” reaming head adapter. This would allow the use of a typical pilot tube installation, followed by a pilot tube to 24-in. diameter reaming head (common), then a short length of 24-in. casing, and then the 24- to 60-in. rocket ship. When reviewing the onsite soil conditions, it was found the onsite conditions were favorable to this type of installation. The soil borings provided showed the crossing traveling through a brown silty clay with trace sand and gravels on the upstream side with a brown sandy clay on the downstream side. These conditions led to the decision to proceed with this course of action.
The 24- to 60-in. reaming head was constructed using heavy wall steel casing and T1 steel for the cutting arms. The arms were constructed of T1 steel to withstand the jacking forces to be applied in this application. The reaming head and auger configuration allowed for a short piece of 24-in. auger to be installed in front of the 60-in. auger allowing the ingestion of earth ribbons thru the front section of the reamer, thus creating the 24-in. hole. The back end of the reamer was constructed in a similar manner. The 24-in. by .5-in. wall casing acted as the connection point for the cutting arms for the 60-in. section. The 60-in. section was constructed of 60-in. by .875-in. steel casing. This extension off the back end of the reamer allowed for the actual 60-in. casing as carrier to be affixed to the “rocket ship” for installation.
Ground Conditions
As installation began, the ground conditions were found to be even better than expected. The pilot tubes were installed without any problems. With the installation of the pilot on line and grade, the pilot tube to 24-in. reaming head was lowered into the main work pit to get all the required measurements for appropriate auger length to be installed inside the 24-in. and 60-in. casing. The auger was ran out into the 24-in. reaming section and the 60-in. reaming section as far as possible but still leaving enough room for the auger to “grow” as sections were added in the work pit. This eliminated the possibility of the auger being advanced into the back side of both reaming sections but kept the auger close enough to the earth ribbons being cut to be picked up as quickly as possible. With the proper spacing of the auger inside each section of casing spoil was removed efficiently and the actual push pressure remained low during the reamer advancement.
During casing advancement, a bentonite slurry mix was also introduced throughout the entire crossing to aid in the reduction of friction on the exterior of the steel casing carrier. On average, bentonite was pumped about 400 gals per 20-ft length of casing pipe. While the amount was found to be excessive, it was imperative to do whatever it took to limit the jacking force involved as to not exceed the push capacity of an American Augers 60-1200 auger boring machine. With this rate of bentonite introduction combined with the proper auger placement, the actual pushing pressure never exceeded 75 tons.
Initial production during installation was around 40 ft per day. Once the crew became accustomed to the setup and a routine was established, a production of 60 ft per day was observed. Careful, detailed planning in combination with excellent execution allowed this project to be completed ahead of schedule and under budget.
Brent Hofer is a project manager at Midwest Mole, based in Indianapolis.
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Category: News
Midwest Mole Promotes Miller
Midwest Mole Inc. announced the promotion of Jason Miller to president from vice president, effective Aug. 28. Miller is taking over the post from Dan Liotti, who announced he will assume the role of CEO.
“Jason has not only the ability, but also has the passion and desire that it takes to be the president of Midwest Mole and to lead us into our 31st year of business,” said Liotti. “This will allow me to focus my time on business development, client relations and industry partnerships and the visionary aspects of a CEO position.”
Miller joined Midwest Mole as a laborer in 1995 before moving into project estimating and later serving as the company’s vice president. As president, he will be responsible for the oversight and direction of its field operations, the company’s overall direction and day-to-day business operations. Liotti will continue to manage the company’s finances.
Since 1982, Midwest Mole has earned its reputation as a leading contractor in the trenchless technology industry, providing a broad range of underground services to municipal, utility, highway, railroad and private sector customers.
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NEW INSTALL HONORABLE MENTION
Wolf Bay Crossing Project
PowerSouth’s Wolf Bay Crossing Project in Orange Beach, Ala., is a multi-faceted example of challenges and innovation in HDD and complex installation of large-scale underground electrical transmission lines subject to specifically engineered thermal grout requirements. The installation — which is now the longest of its kind in the United States — doubled the record of thermal grout used in conjunction with HDD and had the longest length of continuous cross-linked polyethylene insulated (XLPE) cable rated at 115-121kV and 300MVA. The installation involved approximately 6,200 ft of 36-in. diameter steel casing pipe installed by HDD pilot hole intersect and HDD-assist methods under Wolf Bay in Alabama. This included crossing under an intracoastal waterway channel while reaching depths of up to 110 ft. Approximately 220 ft of 60 in. conductor casing was used to protect the active substation at the southern end of the crossing from impacts of the HDD process. A 36-in. diameter steel casing pipe was installed by HDD throughout the 6,200-ft long crossing. Once the 36-in. steel casing was installed, multiple HDPE pipes were bundled and pulled together into the casing with stainless steel bands spaced throughout the length of the bundle. Before the cable was installed, a completed bore path profile was generated and used in developing a strategy for the thermal grout operation in order to fill the extraordinary length and volume of fill specified by design requirements. Thermal grout is installed around underground conduits to remove heat caused by high voltage power transmission.
Project Owner: PowerSouth Energy Cooperative
Engineer: Waldemar S. Nelson and Co.
Contractor: Southeast Directional Drilling
Shively Interceptor Project
The Shively Interceptor Project in Shively, Ky., is the third largest pilot tube microtunnel (PTM) project ever completed in the United States, and arguably the most challenging. The project consisted of the installation of more than 10,678 lf of vitrified clay pipe (VCP) with a total grade change of less than 13 vf over the entire alignment. The breakdown of footage by diameter is as follows: 1,228 lf of 27-in VCP, 733 lf of 21-in. VCP, 4,280 lf of 18-in. VCP, and 4,437 lf of 15-in. VCP. The trenchless crossings required (three each) 12 ft-diameter shafts ( two – secant pile, one – internally braced sheet pile cell), and (34 each) 9-ft diameter shafts ranging from 17 to 35 ft deep. The soil conditions consisted of loose, medium dense, coarse sands below the water table to loose, fine sand above the water table. The PTM method was the only choice for installation of this sanitary sewer pipeline. The extreme depths, soil conditions and extremely flat design grades would have made an open-cut installation of this sanitary sewer in the middle of a tight residential area nearly impossible and would have had a severe impact on the residents of Shively. The specified approach of PTM saved Louisville MSD a substantial amount of taxpayer dollars and allowed the residents of Shively to maintain their day to day lives with minimal impact.
Project Owner: Louisville MSD
Engineer: Louisville MSD
Contractor: Midwest Mole
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Midwest Mole Turns 30
The trenchless technology market has come a long way in the past 30 years. In fact, 30 years ago the term “trenchless technology” was not commonly used in the industry lexicon. At that time, there were no professional societies directly related to the market, very little research and educational efforts, and a handful of manufacturers offering equipment. It was an “underground” market in more ways than one.
It was in this environment in 1982 that Len Liotti launched Midwest Mole, a boring, jacking and tunneling contractor, in Indianapolis. Over the years, the company has grown right along with the trenchless industry, expanding its footprint in terms of geography and services offered. In June, the company hosted an open house to mark the completion of its new offices and equipment facility in Greenfield, Ind., coinciding with the company’s 30th anniversary celebration.
Midwest Mole is now in its second generation of leadership under Dan Liotti, who worked his way up through his father’s company and has seen the industry change immensely since he began full-time with the company in 1985. Like Len, Dan is a Purdue University engineering graduate (and Dan’s two sons, Brian and Mike, are third-generation Purdue engineers). “When I first started, there was very little known about the industry as a whole,” he said. “I am amazed by the amount of education available now. The North American Society for Trenchless Technology is flourishing, there are engineers who promote the fact that they specialize in trenchless designs, and there are a number of people involved in academia. It is amazing to see how far the industry has come.”
And just like the industry itself, Midwest Mole has come a long way. Roots of the company date back to the early 1960s, when Len Liotti got involved with his first auger boring job while working as a sales engineer at Armco Steel, which at that time was one of the largest boring, jacking and tunneling contractors in the country. Liotti later joined Affholder Inc., which further expanded his knowledge of the underground construction business. When Affholder closed its Indianapolis office in the early 1980s amid a flat market, Liotti saw an opportunity in the local market and founded Midwest Mole in February 1982.
Liotti was able to bring in some of his former coworkers at Affholder and Armco in the early days as the company was making a name for itself. The ability to invest in the right people is a trait that exists in the company to this day, and is a key reason the company has continued to grow, said Dan Liotti. “The dedication, longevity and the knowledge of our people has been the key to our growth and our ability to survive the challenges and ups and downs in our industry. We have many people who have been with us for well over 10 years.”
One of those employees is Jason Miller, also a second-generation Midwest Mole employee who serves as executive vice president of the company. Miller joined Midwest Mole as a laborer in 1995 before moving into project estimating. “It is the people who make Midwest Mole different from other companies. Len started the company with good leadership, we continue to have good leadership today, and that trickles down to everyone in the company,” he said. “You can buy new equipment and you can build a new building, but without the right people none of that matters.”
Through the years, Midwest Mole has expanded its service offerings. The company has always maintained its base as a jacking and boring contractor, but has added new tools included TBMs, guided boring/pilot tube tunneling, vacuum-assisted boring (Vermeer AXIS system) and rehab, including sliplining and grouted-in-place liners.
“In the past few years we have moved more into the rehab market, which is a good niche for us,” Dan Liotti said. “Our guys are used to working underground and working inside pipes, and we are experienced in building shafts. That has helped us stay busy as we have seen a slowdown in some of the new installation work that we were traditionally doing.”
The magnitude of some of the projects has also increased. In 2007, Midwest Mole completed the construction of an $8 million new utility tunnel for the Indianapolis International Airport, a project that was named the Trenchless Technology Project of the Year. More recently, the company served as prime contractor on a $14 million project in Claremont County, Ohio, which involved the installation of 9,000 ft of 72-in. tunnel. Also notable, was a project in Louisville, Ky., that included more than 10,000 ft of clay pipe installation using guided boring, one of the largest guided boring projects completed to date in the United States.
Recently, the company entered into a partnership with Triad Engineering and Contracting from Cleveland, Ohio, on a project in Charleston, S.C., which is something that Miller sees as a potential future trend. “Creating partnerships and joint ventures is an area that we could grow into,” he said. “We have never looked to grow for growth’s sake, but if opportunities arrive that make sense for our company and are a good fit, we will take advantage of them.”
As the company has grown, so has its geographic footprint. Traditionally, the company operated within a five-hour driving radius from its Indianapolis base. More recently, however, the company opened an office in the Washington, D.C., area that is now headed by Steve Abernathy, Midwest Mole vice president.
“We have to look a little farther outside our typical geographic area in the past few years,” Miller said. “We opened an office in Washington, D.C., and we have been as far west as Phoenix. If the project is right and it fits our equipment and people, then it is not off the table whereas five years ago it might have been.”
It is that adapting and evolving with the industry that has also been an important part of the company’s success — 30-plus years of experience in the industry also helps. “We have been fortunate to retain an experienced staff and now we are able to avoid some of the mistakes that we may have made 10 years ago,” Liotti said. “If you make a mistake in this business you can take some big losses. We have improved the way we control projects and do a better job of avoiding the big hiccups.”
The company’s commitment to safety is another key element to the success of the company, as it has helped keep it viable in the private sector. “We have always been committed to safety, but within the last five years we formalized that commitment by hiring a full-time safety director, Gary Gagliardi,” Liotti said. “That was a big leap for a small- to medium-size contractor to invest in that position, but our ability to work safe has allowed us to work for private clients that require a strong track record of safety.”
While people are key to success, purchasing and maintaining a fleet of equipment is a huge part of running a successful underground contracting outfit, Liotti says. Midwest Mole has always purchased its own equipment whenever possible. “Through the years, it has been our philosophy to purchase equipment so that when the next job came around we would have the equipment in our fleet and be able to react quickly. We have placed an emphasis on maintaining and supporting the equipment, and that has been a big plus for us.”
Midwest Mole’s new building features a state-of-the-art facility that helps keep the all-important tools up and running. “Equipment that is ready to perform as it is designed is critical to the success of any construction organization,” said Eric Dudley, equipment manager. “If the equipment does not run then the job stops. Field repairs are expensive in many ways. First and most importantly is the cost of lost production followed by the field labor costs when the men cannot work. Last, when repairs must be made in the field, the opportunity to make the most cost-efficient repair is often missed.”
Midwest Mole has always tried to stay on the forefront of technology and has a close and long-lasting relationship with many of the equipment manufacturers. “Akkerman’s relationship with Midwest Mole goes back to late 1970s when my father, Don, started doing business with Len Liotti,” said Maynard Akkerman, now president of Akkerman. “Midwest Mole has always been an advocate of using the latest technology, and their honesty and integrity have always been appreciated.”
Now that the company has marked its 30th anniversary and settled into a new headquarters, Dan Liotti marvels at how far the company has come. Through it all, he sees the lasting legacy that his father, who passed away in 2010, has on the company today.
“My Dad was such a hard worker and had an engineering mind,” Liotti recalls. “He’d draw plans five, six times and make sure it was right. His attention to detail was probably the No. 1 thing he taught me and all of us at the company. His attention to detail and willingness to do whatever it takes to get the job done right are still followed today.”
Jim Rush is editor of Trenchless Technology.
Midwest Mole Through the Years
Midwest Mole has graced the cover of Trenchless Technology twice in our 20 years of publication. The first time being November 2002, with Dan and Len Liotti on the cover with some of the company’s auger boring equipment, and the other in October 2007, when the company was part of the winning team for the 2007 Trenchless Technology Project of the Year award for the Indianapolis International Airport Utility Connector Tunnel project. The project represents the values for which the company strives. “Midwest Mole’s philosophy for each project is to approach it with the mindset that we are going to exceed our client’s expectations by solving their underground construction problems safely, efficiently and with a sense of urgency,” said Joe Butor, field operations manager. “We accomplish this by taking the time to understand the entire project, developing a detailed work plan, selecting the appropriate resources to complete the project, and executing our plan with precision and accuracy. Our professional approach to each project, along with an intense focus on safety, sets us apart from our competitors.”
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Midwest Mole Moves to New Facility
Midwest Mole Inc., an Indianapolis-based contracting firm specializing in trenchless technology, will move into a new facility located in Greenfield, Ind., which is approximately 10 miles east of its existing headquarters. Occupancy was to be completed by April 13.
“My father Len and I purchased our current office and shop back in 1990, and it has served us very well for 22 years,” said Midwest Mole president Dan Liotti. “Our business has grown to the point where we really needed new space. We nearly doubled our square footage with this move.”
The new building is 25,547 sq ft and occupies 13 acres, providing plenty of space for the shop, office, yard and Midwest Mole employees. It also features a large training room that will be used for both in-house meetings and safety instructional seminars.
“This new space will be much more efficient, and we will be poised for continued growth as we celebrate our 30-year anniversary in 2012,” said Liotti. “It is because of our hardworking and dedicated employees that we are able to take this big step and invest in the future of our company.”
The address of the new facility is 6814 West 350 N, Greenfield, IN 46140; the company phone number remains the same: (317) 545-1335.
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Survey of the North American Pilot Tube Industry
In 2011, researchers at Arizona State University completed a survey of pilot tube microtunneling (PTMT) contractors across North America. The survey was developed in consultation with equipment manufacturers, industry consultants and contractors working with the technology. The intent of the survey was to fill an existing knowledge gap related to the business side of the PTMT industry. While the technology’s applications, capabilities and limitations have been well documented in cases studies, there was little documented literature available on the industry trends, business practices and contractor perspectives on the technology.
Arizona State University contacted approximately 100 contractors via phone, e- mail, and mail and received a total 22 responses from active PTMT contractors. It was found that while many of the contractors contacted indicated they provided PTMT as a service, many of them had not done more than a few trial or demonstration projects. While this response rate was not as high as was hoped, it still provided a good representative sampling of contractors from across the continent. A total of 19 responses were obtained from contractors in the United States, with the other two from Canada.
In total, these 22 contractors completed 5,770 trenchless installation projects (auger boring, horizontal directional drilling (HDD), microtunneling, pipe jacking, pipe ramming and PTMT) in the five years between 2006 and 2010. Of this total, PTMT accounted for 450 projects, or 7.8 percent of the total number of projects undertaken by the respondents. Only one of the contractors indicated he/she solely undertook PTMT projects, with the majority offering PTMT as a complementary trenchless installation method. It was found that the majority of PTMT contractors had been traditional auger boring (80 percent of the respondents) or pipe jacking (70 percent of the respondents) contractors. Several contractors also indicated that they have just started using PTMT within the last three years.
Trends in Utilization
Some significant trends were observed that gauged the health of the trenchless industry as a whole between 2006 and 2010. Figure 1 summarizes the total number of projects undertaken by the survey respondents broken up by methodology. It can be seen that the total number of projects undertaken by these contractors had decreased from a high of 1,328 projects in 2007 to a low of 899 in 2010. This equates to a 33 percent decline in the total number of projects undertaken by the respondents and reflects the prevalent market conditions at that time. While auger boring and pipe jacking saw a decrease of 40 percent and 50 percent in utilization, respectively, by the respondents between 2007 and 2010, PTMT witnessed a 56 percent increase in utilization over that same time period. However, PTMT still only represented 12 percent of the total projects completed by the contractors, with auger boring at 50 percent and horizontal directional drilling at 21 percent making up the majority of installations completed in 2010.
It was found that PTMT is commonly used in conjunction with other trenchless installation methods. The three main hybrid versions of PTMT are: PTMT-auger boring, PTMT-horizontal directional drilling and PTMT-pipe ramming. The idea behind such hybrid methods is to establish an accurate alignment using PTMT’s guided pilot boring followed by product pipe installations by the other technology. Contractors are able to leverage the best of both the technologies in the hybrid system through such methods. PTMT-auger boring is the most widely used method among all the hybrids. Eight five percent of the contractors reported that they had used PTMT in conjunction with auger boring. Continuous plastic pipe can be installed using the PTMT-HDD hybrid method; used by 25 percent of the respondents. Thirty percent of the contractors indicated that they had utilized PTMT in conjunction with pipe ramming.
Productivity
The survey looked to identify factors that affect the productivity of PTMT projects. The responses provided by the contractors were reviewed and categorized by common factors. Figure 2 summarizes the factors and percent of contractors that indicated each factor affected the productivity of a PTMT installation. Ground conditions, including soil type and groundwater table, received the highest rating, with 72 percent of the contractors reporting it as a major factor. Many did not perceive installation depth, as a major factor as the technology, like many of its counterpart trenchless methods, is capable of working at great depths if the ground conditions permit.
The contractors were asked to provide the longest length they had installed in a single drive with pipes of different materials. Fifty percent of the contractors surveyed reported using vitrified clay pipe on their projects. It was observed that 70 percent of the contractors that had used PTMT with VCP pipe recorded their longest drive lengths above 300 ft. Steel pipe was used by 80 percent of the contractors on at least one of their projects. 70 percent of the contractors that used steel pipe recorded their longest drives above 400 ft. The longest drive length among the surveyed projects was 550 ft in which a contractor used steel pipe. Only two of the contractors reported installing concrete pipes with PTMT. The longest drive length, as reported by one contractor, using concrete pipes was 500 ft. It is interesting to note that a drive length of 400 ft had been achieved with HDPE pipe using the hybrid PTMT-horizontal directional drill method.
Project Risks
The survey also asked the contractors to rate risks associated with certain factors and conditions affecting PTMT installations. Table 1 summarizes the results; the rankings were on a scale between 1 and 10 with 10 being the highest level of risk. Survey results indicated that the risk associated with damaging the product pipe and adjacent utilities during an installation had the lowest risk rankings. Approximately, 82 percent of the contractors perceived the damaging of the product pipe as a low risk with an overall risk ranking of 2.2. The highest risks were associated with ground conditions. Sixty eight percent of the contractors indicated clay and silty soils were low risk with a risk ranking of 2.7, while sand and gravel had a much higher risk with a ranking of 6.0, and cobbles and boulders had the highest risk ranking with a score of 9.5, with 91 percent of the contractors indicating it was high risk. While the technology is well applicable in medium to dense sands above the water table, the applicability is marginal in very loose to loose sands above the water table and medium to dense sands below the water table.
Closing
The pilot tube microtunneling method while relatively new to North America, has seen an increase in utilization between 2006 and 2010, while more traditional methods of trenchless installation have seen a minor decrease in utilization over the same time. This technology is ideal for the installation of pipe on tight line and grade for installation lengths generally used between manholes in a municipal setting. As the need to replace buried pipe infrastructure in urban areas increase, it is expected that pilot tube microtunneling will see an increase in utilization due to its low impact and small footprint of operation.
Acknowledgements
The authors would like to express their gratitude and appreciation to Jeff Boschert with the National Clay Pipe Institute for his guidance and assistance in developing the survey, providing contact information and educating us in the art and science of pilot tube microtunneling.
The authors also want to express thanks to the following contractors for their participation in the survey: Aaron Enterprises Inc., York, Pa.; Armadillo Underground Inc., Salem, Ore.; B Trenchless, Henderson, Colo.; Blevins Road Boring, Hudson, Fla.; Bore Master, Inc., Pewaukee, Wis.; Bradshaw Construction Corp., Elliot City, Md.; Brannan Construction Co., Denver; Calgary Tunneling, Calgary, AB, Canada; Claude H. Nix. Construction Co. Inc., Ogden, Utah; Frank Coluccio Construction, Seattle; Kamloops Augering & Boring Ltd., Kamloops, BC, Canada; Magnum Tunneling & Boring, LLC., Houston; Midwest Mole Inc., Indianapolis, IN; North Core, Fargo, N.D.; Pacific Boring Inc., Caruthers, Calif.; Riley Contracting Inc., Norwalk, Ohio; Roddie Inc., Morgan Hill, Calif.; Specialized Services Co., Phoenix; Super Excavators Inc., Menomonee Falls, Wis.; T&D Trenchless, Murrieta, Calif.; and Wayne Arnold Road Boring Co., Smackover, Ark.
Dr. Jason S. Lueke, Ph.D., PEng is an assistant professor at Arizona State University, Del E. Webb School of Construction. Vamseedhar Gottipati, M.S., is BIM scheduler for Enclos Corp, Eagan, Minn.
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New Technologies Expand Capabilities of Auger Boring
If trenchless technology in North America is in its adolescence, then it can be said that auger boring is the grandfather of all trenchless methods. While trenchless methods such as cured-in-place pipe, horizontal directional drilling and microtunneling didn’t come about until the 1970s and later, auger boring had long been an established method for installing pipe with minimal surface disruption.
The roots of auger boring can be traced to coal mines of West Virginia where the technology was used to excavate coal seams beginning in the 1930s (Martin and Grolewski, 2011). For the most part, the basic technology has remained the same with evolutionary improvements in safety, power and capabilities.
The North American Society for Trenchless Technology defines auger boring as “a technique for forming a bore from a drive pit to a reception pit, by means of a rotating cutting head” in which “spoil is removed back to the drive shaft by helically wound auger flights rotating in a steel casing.” Auger boring is typically used for short bores in diameters ranging up to 72 in. and beyond in a range of soil conditions.
One of the historic limitations to auger boring has been in the ability to steer. The traditional method allows for grade accuracy but limited capabilities to steer left and right. Steering the machine involved pulling the augers out and sending workers to the face to make adjustments. In the last decade, however, new methods for installing pipes on line and on grade have had an impact on the auger boring market. Specifically, the development of pilot tube or guided boring methods, which provide precise bores in displaceable soils, can be used in conjunction with auger boring to expand its capabilities.
The pilot tube or guided boring method uses theodolites or lasers in conjunction with a slant-face bit to provide tightly controlled line and grade accuracy in displaceable soil conditions. Once this initial bore is completed, conventional auger boring techniques can be used that follows the alignment of the pilot, allowing for greater accuracy.
“There has been development of the pilot tube guided boring equipment and that technology has really aided the auger boring business,” said Dan Liotti, president of Midwest Mole, a leading trenchless contractor based in Indianapolis. “Once your pilot bore is completed, you connect your leading piece of casing to pilot and that guides your bore. Now we’re able to do very long shots — 300, 400 ft — on really tight line and grade control, which really wasn’t possible before.
“It used to be that auger boring was more of an art because you’re in the pit, 200 ft away from your leading edge, and you had to rely on the feel of the machine and the thrust and push pressures. Now there is a lot more science to the technology.”
While the pilot tube or guided boring technology works well in displaceable soils, other technologies have been developed for use harder ground, including rock up to 25,000 psi, allowing auger boring technology to be used in conditions that were previously left for other methods. These technologies incorporate a cutting head instead of a slant-face bit to complete the pilot bore.
One technology using a cutterhead with rolling disc cutters expands the capabilities of auger boring further, said Arvid Veidmark, executive vice president for Specialized Services Co. (SSC), based in Phoenix. “The new technology enables us to contend with mixed soil and rock conditions that in the past we would have done by hand tunneling. It allows us to contend cobbles and small boulders intermixed wit sand, clay and caliche. It hasn’t changed the foundational process of auger boring; it has just given us the ability to apply it more broadly.”
In addition to steering capabilities, manufacturers are providing machines with more thrust and horsepower, which enable longer drives and larger diameters, said Jimmy Lee, field service technician for American Augers. “It used to be that a 200-ft bore was scary,” he said. “Now we are seeing 600-ft drives with 54-in. pipe. We did a bore of 500-ft with 84-in. pipe. We are reaching out there farther and farther.”
As with any trenchless project, proper planning is the key to success in auger boring. “Proper set up is 85 percent of the job,” Lee said. “I see a lot of problems that arise because the pit is not properly set up. Another factor is taking your time when completing the bore. It is always better in the long run to get it done right the first time.”
Soil investigations are also recommended for auger boring projects, particularly conventional auger boring, which is not conducive for crossing mixed face conditions.
Auger boring has always filled a niche within the trenchless marketplace and recent developments ensure that it will be there for some time to come. “Auger boring is a very solid, cost-effective method of installation, and the advent and incorporation of new technologies allow you to do so much more with the machines than in years past.”
Jim Rush is editor of Trenchless Technology.
AUGER BORING RIG MANUFACTURERS
Akkerman
58256 266th St.
Brownsdale, MN 55918 USA
Phone: 800-533-0386
Website: www.akkerman.com
American Augers
135 US Route 42
West Salem, OH 44287 USA
Phone: 800-324-4930
Website: www.americanaugers.com
Barbco
315 Pekin Ave SE
East Canton, OH 44730 USA
Phone: 800-448-8934
Website: www.barbco.com
Bor-It
1687 Cleveland Ave.
PO Box 789
Ashland, OH 44805 USA
Phone: 419-289-6639
Website: www.bor-it.com
Horizontal Equipment Mfg. Inc.
PO Box 5886
Pinehurst, NC 28374 USA
Phone: 800-544-9914
Website: www.horizontalholes.com
Icon Equipment Distributors Inc./Bohrtec
300 Ryders Ln.
East Brunswick, NJ 08816 USA
Phone: 800-836-5011
Website: www.iconjds.com
McLaughlin Group Inc.
2006 Perimeter Rd.
Greenville, SC 29605 USA
Phone: 800-435-9340
Michael Byrne Mfg.
1855 Earth Boring Rd.
Mansfield, OH 44903 USA
Phone: 800-613-7206
Website: www.byrnegroup.com
The Robbins Company
29100 Hall St
Solon, OH 44139 USA
Phone: 440-248-3303
Website: www.robbinstbm.com
Vermeer Corp.
1210 Vermeer Road East
Pella, IA 50219 USA
Phone: 641-628-3141
Website: www.vermeer.com
Horizontal Boring Helps Update Pioneer Village
Located just north of Phoenix off of the Interstate 17 sits Pioneer Village, a historic park that educates locals and visitors about Arizona’s history in the territorial days from 1863 to 1912. Opened in 1969 by the Arizona Pioneer Association, it has been a popular destination for field trips, serving over 1 million children. In 2010 the private association was no longer able to keep the park open and the City of Phoenix purchased it and began to make improvements to the facilities. One needed upgrade was to the utilities, including an expanded water source to the village.
Specialized Services Co. (SSC) was selected as the horizontal boring subcontractor by Quest Civil Ventures, the general contractor on the project. A 36-in. steel casing would have to cross from the east side of I-17 to the village on the west side to carry a 16-in. water line. I-17 carries three lanes of traffic in each direction at this location creating the need for a 400-ft bore to span the distance, one of the longest bores performed by SSC to date. To add to the challenge, the final foot of the bore on the west side of the freeway would be crossing under a main fiber optic line that serviced the nearby federal prison and a large portion of northern Arizona.
Co-owner of SSC and head of field operations, Abe Veidmark, was up for the challenge. The combination of the length, solid rock soil conditions and extremely critical line and grade made this a job that demanded his leadership and expertise. SSC was equipped to do this job having added a 36-in. Robbins SBU (Small Boring Unit) head to its equipment fleet in 2009. Prior to the use of SBUs, this job would have had to be performed using hand tunnel to contend with the rock conditions. This would have created a footage production rate of 4 ft per day, whereas the SBU was able to generate 20 ft per day.
The bore was started with the SBU and a 36/600 American Augers bore machine. After 200 ft was installed, the weight of the auger was too much for this bore machine and it was replaced with a 48/54 Barbco bore machine which offered greater horsepower to keep the auger spinning. The bore was completed on almost perfect line and grade, finishing only 2 in. to the right and 3 in. low, easily clearing the fiber-optic line and in exact location needed for the open-cut crews to tie onto. Upon conclusion of the bore, the 16-in. waterline was pushed through the steel casing by SSC on stainless steel casing spacers, connecting the historic village to its new water supply.
Article supplied by Specialized Services Co., Phoenix.
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Backreaming Through Rock
Taking on a challenge is nothing out of the ordinary for the experienced trenchless installation experts at Midwest Mole. Since its founding in 1982, the Indianapolis-based contractor has earned a reputation for installation innovation, overcoming obstacles and defying the odds. So, these trenchless pros didn’t hesitate to take on another challenge despite the recognition that they would likely encounter a few unknown and unexpected twists and turns along the way.
Midwest Mole was hired by general contractor Dudley Construction on behalf of project owner Northern Kentucky Sanitation District No. 1 (SD1). SD1 is responsible for the collection and treatment of Northern Kentucky’s wastewater, as well as regional storm water management and is the second largest public sewer utility in the state. The district’s service area covers approximately 220 sq miles in three Northern Kentucky counties, serving more than 30 municipalities and several unincorporated areas. SD1 maintains more than 1,600 miles of sanitary sewer line, more than 140 wastewater pumping stations, several treatment plants and approximately 17,800 storm sewer structures.
This project, located just outside of Florence, Ky., was to install a 506-ft section of 18-in. DR11 HDPE material that would eliminate a pump station and convert the existing sewer from a forced main to gravity flow. It was to be installed at 1.3 percent grade using auger boring as the installation method. The greatest challenge, however, was neither the grade nor the material, or even restricted access to the site — which would necessitate traversing over hilly, heavily-wooded terrain — but as is often the case, it would be ground conditions posing the bigger concern. After reviewing the plan, however, Midwest Mole project manager David Howell had an idea for an alternative approach.
“This was in a residential area with a lot of trees, on a hill and very limited access,” Howell says, “and it was also solid rock. SD1 had designed it to basically be bored through the hill with the auger boring method. We had used an AXIS laser guided boring system on a project before and thought it might be a good fit here. Our only real concern was backreaming through rock.”
How It Works
The AXIS system consists of a vacuum power unit, vacuum tank and the rack power unit, along with drill casing and the drill head. Located outside the launch pit is a high-performance liquid ring vacuum power unit that removes excavated material from the bore. Upon reaching the launch pit, the excavated material transitions from the drill casing to a 6-in. diameter hose that runs up the launch pit to the vacuum tank.
Outside the pit is a self-contained power unit that features a 140-hp diesel engine and hydraulic pumps that connect to a rack (located in the launch pit) that powers rotation, thrust and pullback functions of the drill head and casing.
The operator console is designed to centralize control of multiple components into an easy-to-use interface and consists of the target display monitor, parameter display, drill head steering control, thrust/pullback control, rotation control and vacuum controls. Drill casing segments, measuring 6 1/2-ft long, are placed in the rack carriage and feature a laser sight channel and a vacuum channel for removing excavated material.
The guidance system includes a laser that determines the line and grade of the bore, enabling on-grade accuracy throughout the bore process. The drill head uses a flat-face cutter that when combined with the laser guidance system is capable of completing bores with a strict and precise degree of on-grade accuracy. In standing ground it can be retracted in mid-installation, allowing the contractor to change the cutter bit to adapt to changing soil conditions.
Eliminating a Step Helps Enhance Efficiency
The rock was composed of layered shale with veins of limestone formations ranging from 1 to 5 in. thick and measuring upward of 12,000 psi in density. The overhead power line and an existing pump station located within proximity of where the launch pit area would need to be situated were also factors. However, after verifying the location of the sewer lines currently running in and out of the pump station and sizing up the final measurements for positioning the various components of the AXIS system, Howell was confident that this laser guided boring method was indeed the best approach … and officials with SD1 concurred.
“While we agreed that it certainly would have been possible to complete the job using auger boring, we were able to identify several advantages that favored the AXIS system and presented these findings to officials at our longtime customer SD1. They weren’t all that familiar with this method, but we had worked with them on several prior projects and delighted they trusted our recommendation and gave us the green light.”
Howell cited three important factors that helped tip the scale in favor of the AXIS system, beginning with the rock. The inconsistency of the formation and the variation in limestone and shale layers make it more difficult to maintain an accurate line and grade using auger boring. According to Howell, maintaining a precise grade — often less than 1 percent — is a major advantage for AXIS since the laser guided system allows the operator to continuously monitor the boring process and make instantaneous adjustments when changes in rock density and hardness alter the path of the drill head, albeit ever so slight.
Another important advantage for the AXIS system given the rocky Northern Kentucky terrain, coupled with the smaller-diameter material that was to be installed for the Florence project, is the ability to complete it in one pass.
“Auger boring would have necessitated a two-pass approach,” Howell explains. “The casing pipe would have to be installed first, followed by the new carrier pipe threaded inside that. And likely this approach would also have required that we grout the material in place. Not so using the AXIS system, however, as the carrier pipe could be installed directly in the bore minus the steel casing. So, in essence, we eliminated a step and that equates to less time and reduced expense.”
Midwest Mole used a 13 1/2-in. tri-cone bit for the pilot bore and achieved an average production rate of 14 ft per hour through this complex compilation of rock formations. With the HDPE pipe fused and ready on the receiving end, it was time to face the unknown and begin the backreaming phase of the project.
The one unknown, however, was whether the AXIS system would be able to effectively backream through this difficult formation of limestone, shale and high-density rock, having only pulled product back through the bore on previous installations. Howell’s crew selected a 19 1/4-in. tri-cone cutter head for navigating the 506-ft bore with roller cones — a tooling configuration considered to be effective for removing rock and best positioning the reamer during pullback.
“This was the first time the AXIS system had been used to ream rock, so there was obviously some trial and error involved at first,” Howell says. “We made some adjustments along the way to get the cutter spacing set with the correct over-cut to allow the reamer to work most efficiently. We had a pulling head attached to the back side of the reamer on a swivel, which helps to clear the bore, so we were pulling the product pipe back in as the hole was reamed. We used the standard Vermeer reamer design custom built with roller cone cutting heads.”
Howell admits there were some nervous moments prior to pullback. “We knew that we had thought the project out as thoroughly as possible, but there were still some tense nerves as we approached backreaming time,” Howell says. “Vermeer was there to support us, and yes, there was nervousness doing something for the first time, but all in all things went very well. We had to make some adjustments, but at the end of the day, it actually reamed the rock quite well and we were very pleased with it. We averaged about 8 ft an hour on the backream.”
Randy Happel is a features writer for Two Rivers Marketing, Des Moines, Iowa.
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Obituaries: Len Liotti
Midwest Mole founder Leonard (Len) Liotti, 77, of Apollo Beach, Fla., passed away on Nov. 23.
Liotti was retired from Midwest Mole, an Indianapolis-based trenchless technology and tunneling company he founded in 1982. His son Dan Liotti is now president.
Liotti was born in Buffalo, N.Y., and graduated from Purdue University’s School of Civil Engineering in 1957. He was a licensed professional engineer in the state of Indiana. He became involved in the tunneling industry when he was a sales engineer with Armco Steel back in 1961. Armco had a construction division, which at that time was the largest specialized boring, jacking and tunneling contractor in the nation. Liotti was fascinated with the technology to install casings and tunnels and requested to be transferred from the sales department to the construction division. He took off his coat and tie and went from being a sales engineer to a boring and tunneling superintendent.
In 1971, Len joined Affholder Boring and Tunneling as a regional manager working out of Indianapolis. By the 1980s, Indianapolis, along with the rest of the country was in a recession and Affholder closed its Indianapolis office. Liotti saw an opportunity to open his own business — Midwest Mole in 1982.
Over the next two decades, Midwest Mole pulled together an assortment of trenchless technologies to power its growing customer base in Indiana, Ohio, Illinois and Kentucky. In 2002, Liotti retired from Midwest Mole and his son Dan purchased the company from him.
Liotti is survived by his wife Dianna (Hoeping) Liotti; son, Dan and daughters Jennifer and Diane (Holmes) Liotti and five grandchildren. He was preceded in death by his first wife, Jane (Moser) Liotti.
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Installation Honorable Mentions
Enbridge Alberta Clipper & Southern Lights
Michels Directional Crossings installed 33 crossings in five months for the 36-in. Alberta Clipper and the 20-in. Southern Lights pipeline projects.
Work began near Leonard, Minn., and made its way to Superior, Wis. Michels installed 47,600 ft of 36-in. pipe, with installations varying from 1,300 to 5,200 ft for the Clipper.
The Southern Lights project was 30,837 ft of 20-in. pipe, with crossings ranging from 1,000 to 5,200 ft. Michels sent nine of its 14 large capacity drill rigs to work on the project at one time — the first time in Michels’ long history that it has resourced out so many for one contract within a 150-mile radius.
Temperatures ranged from the mid-80s to 20-below F, making the conditions extremely challenging. Additionally, while working on the project, Michels executed three HDD pullbacks in one day.
Project Owner: Enbridge
Engineer: J.D. Hair & Associates
Contractor: Michels Corp.
Microtunneling Under Lake Oahe in South Dakota
Michels Tunneling was contracted to bore a 950-ft tunnel underneath South Dakota’s Lake Oahe, a project that was supported with $18.9 million in economic stimulus funds. The water intake pipeline will provide drinking water to the Standing Rock Sioux tribe reservation. Michels used an Akkerman Inc. MTBM SL46 to install the 950 ft of 44-in., 16-ft length Permalok pipe. Among the challenges was that Michels anticipated a 60-ft high water table but instead encountered one that was 82 ft high, increasing the project’s difficulty.
Michels had to drill a 110-ft deep caisson with a diameter of 20 ft on the shore to launch the machine. Also, the underwater retrieval of the MTBM became much more difficult with the additional water table depth, forcing Michels to create new plans to retrieve the machine. Aided by A.D. I. Marine Professionals, Michels performed the wet retrieval of the MTBM. The retrieval process took two days, while the entire tunnel took six weeks.
Project Owner: Standing Rock Sioux Tribe
Engineer: Barlett & West
Contractors: Graham Construction Services Inc.
Subcontractor: Michels Tunneling
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