Trenching is an integral part of installing large-scale transmission pipelines. The machines that perform this work are hulking mammoths that cut anywhere from a few inches to a few feet wide and as deep as 24 ft as they slice a path down the right of way. In their wake, miles of pipeline fill the void left behind, providing transportation to crucial energy resources throughout North America.
Trenchers come in three main varieties: rocksaws, chainsaws and bucket wheels.
Rocksaw trenchers look like oversized circular saws attached to a crawler carrier, and are designed for making narrow and deep cuts in the earth. The machines are typically used for small diameter pipelines, as well as fiber-optic and electrical cable, cutting trenches at widths that range from 2 to 16 in. and up to 5 ft deep.
Chainsaw trenchers likewise appear like a giant version of the hand tool the name brings to mind. These behemoths ensure minimal over-excavation by depositing the spoils in a nice row alongside the trench. The machines are suitable for a variety of widths and depths, from as little 8 in. wide and 5 ft deep and up to 60 in. and 24 ft deep, depending on the model.
Bucket wheels are high-production machines and best used in loose and soft soils and long-distance, interurban projects. The machines can also be equipped to handle permafrost, by installing different digging tools. Bucket wheels cut ditch widths that range from 12 to 84 in. with depths up to 10 ft.
Alvarado, Texas-based Tesmec USA Inc. is one of the foremost providers of trenchers in North America. The company has been manufacturing trenching machines since its founding in 1984. Tesmec USA is a subsidiary of Tesmec S.p.A., founded in 1951 and headquartered near Milan, Italy. Three of the company’s experts sat down with me to discuss a series of topics related to the trenching market and the oil and gas pipeline industry.
Bryan Blankenship is national sales manager at Tesmec. He has more than 25 years of construction and heavy equipment experience with companies like Caterpillar, Putzmeister, Zoomlion/CIFA and Hyster Co. Blankenship has been directly involved in the trenching business for six years.
John Welch is the company’s chief engineer and has been working with Tesmec for 32 years. In fact, he developed the first Tesmec trencher. Welch has knowledge and understanding of all things related to digging ditches by mechanized means regarding the use of Trenchers.
Preston Renfro is production manager at Tesmec. He started with the company in 2007 and has served a variety of roles, from assembly where he built trenchers from the ground up, to the field service department traveling to various locations to train customers on the equipment and repair any issues that arose in the field. He has also served as rental fleet manager for the company before taking on his current role.
And now, onto the questions …
How would characterize the trenching market today?
Blankenship: The trenching market today is extremely cyclical and is tied to major construction projects throughout North America. We have seen some downturn in the purchase of new trenchers throughout the last six to 12 months. However, our aftermarket service and parts operations have been experiencing growth related to the overall use of today’s existing fleet of trenching machinery.
How have low commodity prices impacted your business?
Blankenship: The price of commodities has some impact on our business, especially in oil, gas and precious metals. Commodity prices are directly related to exploration investment and therefore new pipelines and additional exploration in open pit mining operations.
What trends do you see for the next 18 months?
Blankenship: Our expectations are that second quarter 2017 will begin to see a period of reinvestment into the
gas and oil [sectors] due to an expected rise in the commodity price. Additionally, we are projecting additional investment into cross-country fiber and fiber to the home.
What is the biggest driver of trencher sales in North America?
Blankenship: The biggest driver in trencher sales in North America is gas and oil pipeline investment. Though we see other major factors such as large infrastructure projects, investment in underground utility and fiber, gas and oil pipelines still remain the biggest and most substantial driver of trencher sales.
What’s the biggest argument for using trenchers in oil and gas pipeline installation?
Blankenship: When using trenchers for the opening of the pipeline ditch, we focus on the low cost per foot due to the reduction in manpower necessary to open the same amount of ditch in a given workday. Additionally, the ditch created by the trenchers allows for the same material removed from the ditch to be put back into the ditch therefore minimizing costs associated with crushing or the delivery of virgin selective fill. Overall the trencher is more efficient, has a lower cost per foot to operate and provides a better ditch for installation of pipe.
What is the difference between different trencher types?
Blankenship: Chainsaws come in two different styles, hydrostatic and mechanical. Hydrostatic trenchers are used in highly fractured or compacted material, where material handling is of the utmost importance. With this style of trencher we are able to excavate the material at a very high rate due to the high chain speeds and therefore provide high levels of footage per day. Mechanical trenchers are used mainly in hard rock applications where the material exceeds 6,000 psi in strength. This material is too hard to be cut efficiently by a hydrostatic trencher and too hard to be hammered by excavators. The mechanical trencher features extremely low chain speeds and high chain pull therefore resulting in the excavation of hard rock in chips. These chips can be used as fill for the ditch.
Rocksaws are used for two different type of applications, the first is when there is a need for installation of fiber-optics or small diameter water/gas lines, where high levels of footage are required (fiber will be installed either through the use of a laying boot pulled behind the machine or through the use a vibratory plow; for the installation of water/gas lines the ditch is cleared with a small excavator then the line will be installed). The second use for a rock saw is to precut extremely hard rock prior to a larger chain trencher cutting the ditch behind it. This method is called relief ditch excavation.
Bucket wheels are used in soft material such as dirt, lightly compacted caliche and light rock. Bucket wheels are used for ditch widths ranging from 12 to 84 in. with depths up to 10 ft. Bucket wheels are highly productive and in the right conditions can achieve production ranging from 1 to 2 miles per day.
How do you decide which to use?
Blankenship: The determination on which trencher must be used is based on the type of material that is required to be cut, the type of pipe [or other product] being installed in the ditch and the type of production expectations the customer has.
Is one type more popular among pipeliners?
Blankenship: Depending upon the type of material the pipeliner is operating in determines the type of machine that is being used. In the Marcellus shale play, we see the chainsaw as the primary trencher being used, while in the Bakken shale play we see the bucket wheel as the more popular machine, and while in Eagle Ford we see a mixture of chainsaw and bucket wheel trenchers mainly based on the type of material that is required to be cut.
What are the five most important maintenance guidelines for trenching units?
Blankenship: All maintenance is important on trenchers due to the long lifespan expected from our customers, but from a daily maintenance standpoint it is vital that the operator follow all guidelines put forth in the maintenance manual provided by Tesmec. Important points are air filters, teeth/pockets/baseplates, chain slack, lubing as well as daily checklists.
What the biggest wear points?
Blankenship: Teeth, wear plates and sprockets.
How long should a customer expect a machine to last?
Blankenship: If a machine is properly maintained a machine can last many years, but maintenance, upkeep and types of material the machine is utilized in has a lot to do with machine longevity.
What kinds of technology are customers looking for in a trencher today?
Blankenship: Today’s customers are more involved in the production rates, maintenance and daily reporting services. Therefore, they are asking for systems such as Topcon Tierra provided today by Tesmec that provides real time reports on the machines condition, production rate, maintenance needs and overall fuel consumption.
What innovations have impacted trencher manufacturing in the last five years?
Welch: In the last five years, our significant involvement has been with Tier 4 requirements, development of ultra-low speed digging systems, along with development of advanced technology and CAN-bus control systems.
What advanced technology does Tesmec offer? Automation, GPS, etc.?
Welch: Topcon 3D-GPS for machine depth and guidance control, Topcon Tierra Service for web-based monitoring and telematics.
Can you take me through an operator’s daily walk-around routine?
Renfro: First would be to check all of the fluid levels and air filters of the machine, cleaning air filters as needed. Take a look at the engine and pump compartment. Adjust engine belts if needed for adequate cooling and alternator function. Look over the machine for any unnoticed damage from the day before or leaks that may need attention. Replace any worn teeth and hard surfacing that was not addressed at shutdown on the previous day.
Check and adjust digging chain sag on chain machines. If required, it needs to be done at the start of the day when the chain is cold. Take a look at all baseplate, bucket or segment bolts on the digging attachment, tighten and replace as needed. Inspect track bolts, replace or tighten as needed and adjust tracks if required. Inspect conveyor belt, belt adjustment, conveyor flashing and conveyor lacing. Grease all grease points at the beginning or end of each day.
After this turn on the battery disconnect switch, make sure that machine is clear, start and let the unit warm up before starting work.
End of the day is the same as the start more or less. Trenchers may require more attention than traditional pieces of equipment, but they work hard all day pounding away and pulling material from the ground continuously and more efficiently. Taking care of them equals success on the job.
Tags: September 2016 Print Issue, Tesmec USA Inc.