Truck bodies engineered for rough oil sands conditions
Albert Einstein once said, “the important thing is not to stop questioning.” In the mining industry, a lack of inquisitiveness may lead to a blissful ignorance but it certainly won’t increase efficiencies.
While one may claim necessity is the mother of invention, questioning and analyzing how methods and systems can be improved is the catalyst to discovering necessities. Understandably, when working in the middle of Canada’s oil sands, where trucks operate around the clock every day of the year, it’s nearly impossible to pull the nose from the grindstone long enough to provide thorough analysis. But fortunately some manufacturers/”inventors” have assisted by taking a long hard look at the process and ensuing headaches within this application.
Each day in oil sands mines like the Athabasca oil sands in Fort McMurray, Alberta, 1.5 million tons of moist sand laden with thick, sticky bitumen are loaded into some of the biggest trucks ever manufactured and transported to crushers for the oil extraction process. Time and again, massive shovels dump scoops of 100 tons of the heavy, sticky sand into the unyielding truck beds. Loaded with 400 tons of material, the oil sands trucks then transport and dump the material for separation.
On the surface, it may appear as though truck bodies don’t deviate much from one design to another with their applications deviating even less. However, take a moment or two to speak with an operator about the pain in his/her day and it’s easy to see that assertion couldn’t be further from the truth. Spending some time with operators of mines in the oil sands will quickly reveal the necessity for dedicated oil sands truck bodies designed from the floor up for the challenges specific to these mining operations. The new designs offer enhanced truck body life – raising expectations beyond the meager three years – enhanced performance and improved operator comfort. The result of this quest for answers is now at work in the Athabasca oil sands.
Philippi-Hagenbuch has engineered a High Performance, oil sands specific truck body design currently introduced in the application that address the three major challenges inherent in the grueling oil sands operations. First, the designs are eliminating the loaf effect – that amalgamated and compacted 400-ton block of sand that releases in a loaf, jarring the truck and operator. Second, minimizing “carryback” material, ensuring the bulk of the load is dumped the first time for greater efficiency. Finally, enhancing the life of the truck body well beyond the traditionally accepted three-year replacement point.
Slicing the loaf
It takes little imagination to envision 400 tons of sticky, oil-laden sand jostled and bumped around as it’s hauled on access roads to a dumping point for processing. During that journey, the shaking and jolts result in a vibratory effect that compacts the sands into a firm 400-ton loaf. Much like brown sugar falls in a formed mass from a measuring cup, this sand releases in a solid block once the truck body lifts.
With a significant amount of load over the rear axle, the dumping motion oftentimes causes the front of the truck – which weighs almost a hundred tons on its own – to lift up off of the ground. As the 400-ton loaf releases, the truck and its driver also release from suspension and slam back into the ground. This repeated process stresses both the truck chassis and the drivers, who over time can suffer from back and neck issues caused by the repeated whole body vibration exerted upon them.
High Performance oil sands bodies feature several carefully engineered modifications to assist in slicing up that loaf of compacted sand. A unique bed design features severe tapering of the sides of the truck body. Rather than the traditional parallel-sides of standard truck bodies, which serve as a chute for the compacted loaf, significantly tapered sides effectively increase the opening at the end of the truck bed by 10 to 20 percent. This increased width at the dumping point, removes support from the sides of the loaf, as it is unloaded, allowing successive layers to crumble and drop away from the solid mass.
To further initiate breakdown of the loaf, the back third of the truck floor angles forward from a centre point in the floor to the sidewalls. This angling results in the sides of the truck body floor being significantly shorter than the centre, thus allowing the corners of the load to fall away before the centre of the load reaches the end of the floor. This effectively removes support of the floor from the underside of the loaf edges, forcing it to break apart as it exits the truck body exerting considerably less force on not only the truck chassis, but the driver as well.
The success of these adaptations for mining becomes clear at a glance. After a week running sand, traditional truck walls are polished to a shine from the abrasive load. But following a full year of doing the same in a truck body specifically designed for the oil sands, paint remains on the sidewalls – a true testament to the fact that the load isn’t forced to scrape its way out of the chute.
Cutting the carryback
Just as the oil sands adhere to one another, that same sticky property culminates in material sticking to the traditional truck body floors and walls. This property is evident in a simple walk through the sands, which quickly deposits a half-inch of buildup on the soles of the traveler’s shoes. Imagine what happens under the weight of a 400-ton load. The resulting carryback lessens efficiency and often results in a compounding problem as more and more material sticks and builds in trouble areas. In essence, the same load is carried again and again when it fails to release, taking a joyride back at the expense of the mine. More than 70 tons of carryback material can stay behind, significantly decreasing productivity. Alternatively, the truck operator must stop and manually scrape the carryback from the floor leading to excess labour, wasted time and decreased efficiencies.
Doing the math quickly computes a negative impact on a mine’s bottom line. If, for example, 50 tons of material is left as carryback after the first few trips of the day, and a truck makes two trips per hour – although three to four loads may be the norm – the result translates into a shortfall of 2,000 tons of material that simply is not processed during the course of the day. That’s like a daily free ride to 250 or so bush elephants, the largest living land animals.
The answer to the carryback problem is knocking those elephants off of their feet. High Performance oil sands bodies now incorporate hydrophobic steel in a patent pending way, which effectively prevents the sticking effect.
Hydrophobic steel is characterized by qualities like poor wetting, poor adhesiveness and having a “low” free surface energy/adhesion. These qualities are quickly visible to the untrained eye when one attempts to wet the surface of this steel. The water forms beads upon contact with the surface and any attempt to spread or wet the material results in those water molecules quickly rejoining to beads, refusing to separate, spread or adhere to the material.
Specific oil sands bodies, strategically place hydrophobic materials in key problem areas of the body – those areas prone to sticking and carryback. Typically those problem areas are where two planes of the body intersect, for instance, where the front wall and the sidewall connect or where the front or sidewall connects to the floor. As is common experience with cleaning any surface or material, those crevices and joints tend to be the problem area where material begins to build up. Attaching hydrophobic steel plates to those areas reduces angles, which helps to fight sticking. In addition, the hydrophobic properties repel the sticky material virtually eliminating any carryback. It’s nearly impossible for anything to remain on the truck, whether oil sands or elephants, once gravity comes into play.
As an added benefit, if operators aren’t fortunate enough to have a High Performance Oil Sands body, hydrophobic steel liners can be added as a retrofit to an existing body in order to improve productivity and minimize carryback.
Key as it may be, the hydrophobic material is only one carryback-preventing element of the unique specific oil sands body designs. Operating in far northern reaches of North America, it is easy to understand that environmental conditions can significantly impact performance as well. In areas of the country where temperatures can exceed -40 degrees Celsius and stay there for extended periods, the cold weather serves as another obstacle to effectively releasing the load.
High performance oil sands bodies utilize inherent heating tools found in the byproducts of the truck operation – the truck exhaust – to provide heat to the body reducing the “freezing on” effect that frigid tempers might elicit. Relatively simple in concept and application, the manifold heating system requires careful thought, consideration and engineering.
Different truck chassis provide the exhaust discharge in various locations requiring specific configurations of the manifold system based on the make and model of truck being equipped. Additionally, while effectiveness requires that the heat be applied to areas prone to sticking, distance in routing that exhaust must be short enough to ensure the exhaust does not cool down losing its heating ability and condensing on manifold surfaces. This condensation of the exhaust gases can lead to a combination of the sulfur dioxide within the exhaust and moisture from the condensation combining to form sulfuric acid. Once this acid forms, it can pool within the truck body and result in serious corrosion. Evidence of this can be seen in some truck floors where a simple metal rod can be pushed through the corroded floor of the truck. One exhaust routing system offered by Philippi-Hagenbuch effectively utilizes the exhaust for heating while carefully preventing any direct contact with the truck body floor or structural components of the underside of the truck. As a result, corrosion effects are practically eliminated.
With the intense, around-the-clock work done in North American Oil Sands mines, the life expectancy of traditionally designed truck bodies has been approximately three years. It’s been accepted that the truck body floor will wear through by then due to the abrasive nature of the materials hauled as well as the significant weight and the force with which the load is released dozens of times each day. But expectations need not be lowered as new High Performance dedicated bodies evolve.
The key to any house is a good foundation. If a house isn’t built on a good foundation, it will crumble. The same holds true for truck bodies. To ensure a good foundation, High Performance custom truck bodies run steel bolsters from side to side under the body floor, but unlike traditional bodies, which simply butt-weld the bolsters to the frame rail, High Performance bodies run the bolsters through the frame rails, doubling up the “sweet spot” within the centre floor section.
By intersecting the bolsters with the frame rails, which run from front to back, these custom bodies create a super-structure that won’t buckle under the immense weight of the mined materials.
This enhanced truck design couples with some of the strongest steel in the world to significantly extend the life of the truck. Steel with a Brinnell of 450, which is manufactured in Sweden, has been found to be the strongest, most durable steel available.
High Performance oil sands bodies exclusively use the Swedish steel throughout the entire body – not just the load containing areas. This provides added peace of mind and extended life for the body of the truck. In fact, ultrasonic steel plate thickness tests done on the substance after six intense months in an oil sands mine has shown no appreciable difference in the steel’s thickness. In short, even in the intense environment, the substance isn’t showing signs of wearing thin. That’s expected to increase the life of the trucks by more than 25 percent – an entire extra year of work.
A purpose driven design
All of these changes have transformed the face of mining from an industry making due with available “stock” equipment to one equipped with a focused and engineered fleet dedicated to the specific challenges at hand. And with the size and productivity required in the oil sands industry, that is no small accomplishment. Reflect for a moment on the size and significance of these operations.
Consider that it took 2.6 million cubic metre of concrete to build the Hoover Dam. That same amount of material could pave a 16-foot-wide highway from Seattle, Washington., to Pensacola, Florida. In contrast, that same amount of oil bearing sands material is mined and hauled over the period of just four days.